Chapter 3. APIcast policies

In the Admin Portal, you can enable one or more policies for each 3scale API product.

The 3scale Auth Caching policy caches authentication calls made to APIcast. You can select an operating mode to configure the cache operations.

3scale Auth Caching is available in the following modes:

1. Strict – Cache only authorized calls.

"Strict" mode only caches authorized calls. If a policy is running under the "strict" mode and if a call fails or is denied, the policy invalidates the cache entry. If the backend becomes unreachable, all cached calls are rejected, regardless of their cached status.

2. Resilient – Authorize according to last request when backend is down.

The "Resilient" mode caches both authorized and denied calls. If the policy is running under the "resilient" mode, failed calls do not invalidate an existing cache entry. If the backend becomes unreachable, calls hitting the cache continue to be authorized or denied based on their cached status.

3. Allow – When backend is down, allow everything unless seen before and denied.

The "Allow" mode caches both authorized and denied calls. If the policy is running under the "allow" mode, cached calls continue to be denied or allowed based on the cached status. However, any new calls are cached as authorized.

4. None - Disable caching.

The "None" mode disables caching. This mode is useful if you want the policy to remain active, but do not want to use caching.

Configuration properties

Policy object example

{
  "name": "caching",
  "version": "builtin",
  "configuration": {
    "caching_type": "allow"
  }
}

For information on how to configure policies, see the Creating a policy chain section of the documentation.

The 3scale Batcher policy provides an alternative to the standard APIcast authorization mechanism, in which one call to the 3scale backend (Service Management API) is made for each API request that APIcast receives.

The 3scale Batcher policy caches authorization statuses and batches usage reports, thereby significantly reducing the number of requests to the 3scale backend. With the 3scale Batcher policy you can improve APIcast performance by reducing latency and increasing throughput.

When the 3scale Batcher policy is enabled, APIcast uses the following authorization flow:

The 3scale Batcher policy improves the throughput, but with reduced accuracy. The usage limits and the current utilization are stored in 3scale, and APIcast can only get the correct authorization status when making calls to the 3scale backend. When the 3scale Batcher policy is enabled, there is a period of time in which APIcast is not sending calls to 3scale. During this time window, applications making calls might go over the defined limits.

Use this policy for high-load APIs if the throughput is more important than the accuracy of the rate limiting. The 3scale Batcher policy gives better results in terms of accuracy when the reporting frequency and authorization TTL are much less than the rate limiting period. For example, if the limits are per day and the reporting frequency and authorization TTL are configured to be several minutes.

The 3scale Batcher policy supports the following configuration settings:

The 3scale Referrer policy enables the Referrer Filtering feature. When the policy is enabled in the service policy chain, APIcast sends the value of the 3scale Referrer policy to the Service Management API as an upwards AuthRep call. The value of the 3scale Referrer policy is sent in the referrer parameter in the call.

For more information on how Referrer Filtering works, see the Referrer Filtering section under Authentication Patterns.

The Anonymous Access policy exposes a service without authentication. It can be useful, for example, for legacy applications that cannot be adapted to send the authentication parameters. The Anonymous Access policy supports services with only API Key and App Id / App Key authentication options. When the policy is enabled for API requests that do not have any credentials provided, APIcast will authorize the calls using the default credentials configured in the policy. For the API calls to be authorized, the application with the configured credentials must exist and be active.

Using the Application Plans, you can configure the rate limits on the application used for the default credentials.

Following are the required configuration properties for the policy:

Figure 3.1. Anonymous Access policy

You can use the Camel Service policy to define an HTTP proxy where the 3scale traffic is sent over the defined Apache Camel proxy. In this case, Camel works as a reverse HTTP proxy, where APIcast sends the traffic to Camel, and Camel then sends the traffic on to the API backend.

The following example shows the traffic flow:

All APIcast traffic sent to the 3scale backend does not use the Camel proxy. This policy only applies to the Camel proxy and the communication between APIcast and API backend.

If you want to send all traffic through a proxy, you must use an HTTP_PROXY environment variable.

"policy_chain": [
    {
      "name": "apicast.policy.apicast"
    },
    {
      "name": "apicast.policy.camel",
      "configuration": {
          "all_proxy": "http://192.168.15.103:8080/",
          "http_proxy": "http://192.168.15.103:8080/",
          "https_proxy": "http://192.168.15.103:8443/"
      }
    }
]

The all_proxy value is used if http_proxy or https_proxy is not defined.

For details on using a generic HTTP proxy policy, see Section 3.1.25, “Proxy Service”.

The Conditional Policy is different from other APIcast policies as it contains a chain of policies. It defines a condition that is evaluated on each nginx phase, for example, access, rewrite, log and so on. When the condition is true, the Conditional Policy runs that phase for each of the policies that it contains in its chain.

The following example assumes that the Conditional Policy defines the following condition: the request method is POST.

APIcast --> Caching --> Conditional --> Upstream

                             |
                             v

                          Headers

                             |
                             v

                       URL Rewriting

In this case, when the request is a POST, the order of execution for each phase will be the following:

When the request is not POST, the order of execution for each phase will be the following:

This example checks whether the request path is /example_path:

{
  "left": "{{ uri }}",
  "left_type": "liquid",
  "op": "==",
  "right": "/example_path",
  "right_type": "plain"
}

Both the left and right operands can be evaluated either as liquid or as plain strings. Plain strings are the default.

You can combine the operations with and or or. This configuration checks the same as the previous example plus the value of the Backend header:

{
  "operations": [
    {
      "left": "{{ uri }}",
      "left_type": "liquid",
      "op": "==",
      "right": "/example_path",
      "right_type": "plain"
    },
    {
      "left": "{{ headers['Backend'] }}",
      "left_type": "liquid",
      "op": "==",
      "right": "test_upstream",
      "right_type": "plain"
    }
  ],
  "combine_op": "and"
}

For more details see, policy config schema.

The updated list of variables can be found here: ngx_variable.lua

This example executes the upstream policy when the Backend header of the request is staging:

{
   "name":"conditional",
   "version":"builtin",
   "configuration":{
      "condition":{
         "operations":[
            {
               "left":"{{ headers['Backend'] }}",
               "left_type":"liquid",
               "op":"==",
               "right":"staging"
            }
         ]
      },
      "policy_chain":[
         {
            "name":"upstream",
            "version": "builtin",
            "configuration":{
               "rules":[
                  {
                     "regex":"/",
                     "url":"http://my_staging_environment"
                  }
               ]
            }
         }
      ]
   }
}

The Content Caching policy allows you to enable and disable caching based on customized conditions. These conditions can only be applied on the client request, where upstream responses cannot be used in the policy.

When the Content Caching policy is in a policy chain, APIcast converts a HEAD request to a GET request before sending the request upstream. If you do not want this conversion, do not add the Content Caching policy to a policy chain.

If a cache-control header is sent, it will take priority over the timeout set by APIcast.

The following example configuration will cache the response if the Method is GET.

{
  "name": "apicast.policy.content_caching",
  "version": "builtin",
  "configuration": {
    "rules": [
      {
        "cache": true,
        "header": "X-Cache-Status-POLICY",
        "condition": {
          "combine_op": "and",
          "operations": [
            {
              "left": "{{method}}",
              "left_type": "liquid",
              "op": "==",
              "right": "GET"
            }
          ]
        }
      }
    ]
  }
}

The Cross Origin Resource Sharing (CORS) Request Handling policy allows you to control CORS behavior by allowing you to specify:

The CORS Request Handling policy will block all unspecified CORS requests.

Configuration properties

Policy object example

{
  "name": "cors",
 "version": "builtin",
 "configuration": {
   "allow_headers": [
     "App-Id", "App-Key",
     "Content-Type", "Accept"
   ],
   "allow_credentials": true,
   "allow_methods": [
     "GET", "POST"
   ],
   "allow_origin": "https://example.com",
   "max_age" : 200
  }
}

For information about how to configure policies, see Modifying policy chains in the 3scale API Management Admin Portal.

The Custom Metrics policy adds the availability to add metrics after the response sent by the upstream API. The main use case for this policy is to add metrics based on response code status, headers, or different NGINX variables.

{
  "name": "apicast.policy.custom_metrics",
  "configuration": {
    "rules": [
      {
        "metric": "error",
        "increment": "{{ resp.headers['increment'] }}",
        "condition": {
          "operations": [
            {
              "right": "{{status}}",
              "right_type": "liquid",
              "left": "400",
              "op": "=="
            }
          ],
          "combine_op": "and"
        }
      }
    ]
  }
}

This policy increments the hits metric with the status_code information if the upstream API return a 200 status:

{
  "name": "apicast.policy.custom_metrics",
  "configuration": {
    "rules": [
      {
        "metric": "hits_{{status}}",
        "increment": "1",
        "condition": {
          "operations": [
            {
              "right": "{{status}}",
              "right_type": "liquid",
              "left": "200",
              "op": "=="
            }
          ],
          "combine_op": "and"
        }
      }
    ]
  }
}

The Echo policy prints an incoming request back to the client, along with an optional HTTP status code.

Configuration properties

Policy object example

{
  "name": "echo",
  "version": "builtin",
  "configuration": {
    "status": 404,
    "exit": "request"
  }
}

For information about how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

The Edge Limiting policy aims to provide flexible rate limiting for the traffic sent to the backend API and can be used with the default 3scale authorization. Some examples of the use cases supported by the policy include:

You can scope any limit by service or globally.

key is an object that is defined by the following properties:

Each limit also has some parameters that vary depending on their type:

You can define several limits for each service. In case multiple limits are defined, the request can be rejected or delayed if at least one limit is reached.

{
  "key": { "name": "{{ jwt.sub }}", "name_type": "liquid" },
  "count": 10,
  "window": 60
}

For more information about Liquid support, see Section 4.1, “Using variables and filters in policies”.

condition is defined by the following properties:

"condition": {
  "combine_op": "and",
  "operations": [
    {
      "op": "==",
      "right": "GET",
      "left_type": "liquid",
      "left": "{{ http_method }}",
      "right_type": "plain"
    }
  ]
}

The Header Modification policy allows you to modify the existing headers or define additional headers to add to or remove from an incoming request or response. You can modify both response and request headers.

The Header Modification policy supports the following configuration parameters:

Each operation consists of the following parameters:

Policy object example

{
  "name": "headers",
  "version": "builtin",
  "configuration": {
    "response": [
      {
        "op": "add",
        "header": "Custom-Header",
        "value_type": "plain",
        "value": "any-value"
      }
    ],
    "request": [
      {
        "op": "set",
        "header": "Authorization",
        "value_type": "plain",
        "value": "Basic dXNlcm5hbWU6cGFzc3dvcmQ="
      },
      {
        "op": "set",
        "header": "Service-ID",
        "value_type": "liquid",
        "value": "{{service.id}}"
      }
    ]
  }
}

For information about how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

As an API provider, you can add the HTTP Status Code Overwrite policy to an API product. This policy lets you change an upstream response code to a response code that you specify. 3scale applies the HTTP Status Code Overwrite policy to the response codes sent from the upstream service. In other words, when an API that 3scale exposes returns a code that does not fit your situation, you can configure the HTTP Status Code Overwrite policy to change that code to a response code that is meaningful for your application.

In a policy chain, any policies that produce response codes that you want to change must be before the HTTP Status Code Overwrite policy. If there are no policies that produce Status Codes that you want to change, then the policy chain position of the HTTP Status Code Overwrite policy does not matter.

In the Admin Portal, add the HTTP Status Code Overwrite policy to a product’s policy chain. In the policy chain, click the policy to specify the upstream response code that you want to change and the response code that you want returned instead. Click the plus sign for each additional upstream response code that you want to overwrite. For example, you could use the HTTP Status Code Overwrite policy to change upstream 201, "Created", response codes, to 200, "OK", response codes.

Another example of a response code that you might want to change is the response when a content limit is exceeded. The upstream might return 413, payload too large, when a response code of 414, request-URI too long, would be more helpful.

An alternative to adding the HTTP Status Code Overwrite policy in the Admin Portal is to use the 3scale API with a policy chain configuration file.

{
  "name": "statuscode_overwrite",
  "version": "builtin",
  "configuration": {
    "http_statuses": [
      {
        "upstream": 201,
        "apicast": 200
      },
      {
        "upstream": 413,
        "apicast": 414
      }
    ]
  }
}

The HTTP2 Endpoint policy enables the HTTP/2 protocol and Remote Procedure Call (gRPC) connections between consumer applications that send requests and APIcast. When the HTTP2 Endpoint policy is in a product’s policy chain, the entire communications flow, from a consumer application that makes a request, to APIcast, to the upstream service, can use the HTTP/2 protocol and gRPC.

When the HTTP2 Endpoint policy is in a policy chain:

The IP Check policy is used to deny or allow requests based on a list of IPs.

Configuration properties

Policy object example

{
  "name": "ip_check",
  "configuration": {
    "ips": [ "3.4.5.6", "1.2.3.0/4" ],
    "check_type": "blacklist",
    "client_ip_sources": ["X-Forwarded-For", "X-Real-IP", "last_caller"],
    "error_msg": "A custom error message"
  }
}

For information about how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

Based on JSON Web Token (JWT) claims, the JWT Claim Check policy allows you to define new rules to block resource targets and methods.

If the JWT Claim Check policy is blocking a resource and a method, the policy also validates the JWT operations. Alternatively, in case that the method resource does not match, the request continues to the backend API.

Example: In case of a GET request, the JWT needs to have the role claim as admin, if not the request will be denied. On the other hand, any non GET request will not validate the JWT operations, so POST resource is allowed without JWT constraint.

{
  "name": "apicast.policy.jwt_claim_check",
  "configuration": {
      "error_message": "Invalid JWT check",
      "rules": [
          {
              "operations": [
                  {"op": "==", "jwt_claim": "role", "jwt_claim_type": "plain", "value": "admin"}
              ],
              "combine_op":"and",
              "methods": ["GET"],
              "resource": "/resource",
              "resource_type": "plain"
          }
      ]
  }
}

This policy responds to the API request with a JSON, containing the objects and values that are available in the context and can be used for evaluating Liquid templates. When combined with the 3scale APIcast or upstream policy, Liquid Context Debug must be placed before them in the policy chain in order to work correctly. To avoid circular references, the policy only includes duplicated objects once and replaces them with a stub value.

An example of the value returned by APIcast when the policy is enabled:

    {
      "jwt": {
        "azp": "972f7b4f",
        "iat": 1537538097,
        ...
        "exp": 1537574096,
        "typ": "Bearer"
      },
      "credentials": {
        "app_id": "972f7b4f"
      },
      "usage": {
        "deltas": {
          "hits": 1
        },
        "metrics": [
          "hits"
        ]
      },
      "service": {
        "id": "2",
        ...
      }
      ...
    }

The Logging policy has two purposes:

You can combine the Logging policy with the global setting for the location of access logs. Set the APICAST_ACCESS_LOG_FILE environment variable to configure the location of APIcast access logs. By default, this variable is set to /dev/stdout, which is the standard output device. For further details about global APIcast parameters, see APIcast environment variables.

Additionally, the Logging policy has these features:

local cjson = require('cjson')
local PolicyChain = require('apicast.policy_chain')
local policy_chain = context.policy_chain

local logging_policy_config = cjson.decode([[
{
  "enable_access_logs": false,
  "custom_logging": "\"{{request}}\" to service {{service.id}} and {{service.name}}"
}
]])

policy_chain:insert( PolicyChain.load_policy('logging', 'builtin', logging_policy_config), 1)

return {
  policy_chain = policy_chain,
  port = { metrics = 9421 },
}

docker run --name apicast --rm -p 8080:8080 \
    -v $(pwd):/config \
    -e APICAST_ENVIRONMENT=/config/custom_env.lua \
    -e THREESCALE_PORTAL_ENDPOINT=https://ACCESS_TOKEN@ADMIN_PORTAL_DOMAIN \
    quay.io/3scale/apicast:master

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false
  }
}

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false,
    "custom_logging": "[{{time_local}}] {{host}}:{{server_port}} {{remote_addr}}:{{remote_port}} \"{{request}}\" {{status}} {{body_bytes_sent}} ({{request_time}}) {{post_action_impact}}",
  }
}

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false,
    "custom_logging": "\"{{request}}\" to service {{service.id}} and {{service.serializable.name}}",
  }
}

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false,
    "enable_json_logs": true,
    "json_object_config": [
      {
        "key": "host",
        "value": "{{host}}",
        "value_type": "liquid"
      },
      {
        "key": "time",
        "value": "{{time_local}}",
        "value_type": "liquid"
      },
      {
        "key": "custom",
        "value": "custom_method",
        "value_type": "plain"
      }
    ]
  }
}

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false,
    "custom_logging": "\"{{request}}\" to service {{service.id}} and {{service.name}}",
    "condition": {
      "operations": [
        {"op": "==", "match": "{{status}}", "match_type": "liquid", "value": "200"}
      ],
      "combine_op": "and"
    }
  }
}

{
  "name": "apicast.policy.logging",
  "configuration": {
    "enable_access_logs": false,
    "custom_logging": "\"{{request}}\" to service {{service.id}} and {{service.name}}",
    "condition": {
      "operations": [
        {"op": "==", "match": "{{status}}", "match_type": "liquid", "value": "200"},
        {"op": "==", "match": "{{status}}", "match_type": "liquid", "value": "500"}
      ],
      "combine_op": "or"
    }
  }
}

The Maintenance Mode policy to allows you reject incoming requests with a specified status code and message. It is useful for maintenance periods or to temporarily block an API.

Configuration properties

The following is a list of possible properties and default values.

{
  "policy_chain": [
    {"name": "maintenance-mode", "version": "1.0.0",
    "configuration": {"message": "Be back soon..", "status": 503} },
  ]
}

{
    "name": "maintenance_mode",
    "version": "builtin",
    "configuration": {
        "message_content_type": "text/plain; charset=utf-8",
        "message": "Echo API /test is currently Unavailable",
        "condition": {
            "combine_op": "and",
            "operations": [
                {
                    "left_type": "liquid",
                    "right_type": "plain",
                    "op": "==",
                    "left": "{{ original_request.path }}",
                    "right": "/test"
                }
            ]
        },
        "status": 503
    }
}

For information about how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

NGINX automatically checks some request headers and rejects requests when it cannot validate those headers. For example, NGINX rejects requests that have If-Match headers that NGINX cannot validate. If you want NGINX to skip validation of particular headers, add the NGINX Filter policy.

When you add the NGINX Filter policy, you specify one or more request headers for which you want NGINX to skip validation. For each header that you specify, you indicate whether or not to keep the header in the request. For example, the following JSON code adds the NGINX Filter policy so that it skips validation of If-Match headers but keeps If-Match headers in requests that are forwarded to the upstream server.

{ "name": "apicast.policy.nginx_filters",
  "configuration": {
    "headers": [
      {"name": "If-Match", "append": true}
    ]
  }
}

The next example also skips validation of If-Match headers but this code instructs NGINX to delete If-Match headers before sending requests to the upstream server.

{ "name": "apicast.policy.nginx_filters",
  "configuration": {
    "headers": [
      {"name": "If-Match", "append": false}
    ]
  }
}

Regardless of whether or not you append the specified header to the request that goes to the upstream server, you avoid an NGINX 412 response code when NGINX cannot validate a header that you specify.

This policy executes OAuth 2.0 Mutual TLS Client Authentication for every API call.

An example of the OAuth 2.0 Mutual TLS Client Authentication policy JSON is shown below:

{
  "$schema": "http://apicast.io/policy-v1/schema#manifest#",
  "name": "OAuth 2.0 Mutual TLS Client Authentication",
  "summary": "Configure OAuth 2.0 Mutual TLS Client Authentication.",
  "description": ["This policy executes OAuth 2.0 Mutual TLS Client Authentication ",
    "(https://tools.ietf.org/html/draft-ietf-oauth-mtls-12) for every API call."
  ],
  "version": "builtin",
  "configuration": {
    "type": "object",
    "properties": { }
  }
}

The OAuth 2.0 Token Introspection policy allows validating the JSON Web Token (JWT) token used for services with the OpenID Connect (OIDC) authentication option using the Token Introspection Endpoint of the token issuer (Red Hat Single Sign-On).

APIcast supports the following authentication types in the auth_type field to determine the Token Introspection Endpoint and the credentials APIcast uses when calling this endpoint:

Regardless of the setting in the auth_type field, APIcast uses Basic Authentication to authorize the Token Introspection call (Authorization: Basic <token> header, where <token> is Base64-encoded <client_id>:<client_secret> setting).

The response of the Token Introspection Endpoint contains the active attribute. APIcast checks the value of this attribute. Depending on the value of the attribute, APIcast authorizes or rejects the call:

The policy allows enabling caching of the tokens to avoid calling the Token Introspection Endpoint on every call for the same JWT token. To enable token caching for the Token Introspection Policy, set the max_cached_tokens field to a value from 0, which disables the feature, and 10000. Additionally, you can set a Time to Live (TTL) value from 1 to 3600 seconds for tokens in the max_ttl_tokens field.

As an API provider, you can add the On Fail policy to an API product. When the On Fail policy is in a policy chain and execution of a policy fails for a given API consumer request, APIcast does the following:

The On Fail policy is useful when APIcast cannot process a policy, perhaps because of an incorrect configuration or because of non-compliant code in a custom policy. Without the On Fail policy in the policy chain, APIcast skips a policy it cannot apply, processes any other policies in the chain, and sends the request to the upstream API. With the On Fail policy in the policy chain, APIcast rejects the request.

In a policy chain, the On Fail policy can be in any position.

In the Admin Portal, add the On Fail policy to a product’s policy chain. In the policy chain, click the policy to specify the status code that you want APIcast to return when it applies the On Fail policy. For example, you could specify 400, which indicates a bad request from the client.

You can use the Proxy Service policy to define a generic HTTP proxy where the 3scale traffic will be sent using the defined proxy. In this case, the proxy service works as a reverse HTTP proxy, where APIcast sends the traffic to the HTTP proxy, and the proxy then sends the traffic on to the API backend.

The following example shows the traffic flow:

All APIcast traffic sent to the 3scale backend does not use the proxy. This policy only applies to the proxy and the communication between APIcast and API backend.

If you want to send all traffic through a proxy, you must use an HTTP_PROXY environment variable.

"policy_chain": [
    {
      "name": "apicast.policy.apicast"
    },
    {
      "name": "apicast.policy.http_proxy",
      "configuration": {
          "all_proxy": "http://192.168.15.103:8888/",
          "https_proxy": "https://192.168.15.103:8888/",
          "http_proxy": "https://192.168.15.103:8888/"
      }
    }
]

The all_proxy value is used if http_proxy or https_proxy is not defined.

The Rate Limit Headers policy adds RateLimit headers to response messages when your application subscribes to an application plan with rate limits. These headers provide useful information about the configured request quota limit and the remaining request quota and seconds in the current time window.

In the policy chain for a product, if you add the Rate Limit Headers policy it must be before the 3scale APIcast policy. If the 3scale APIcast policy is before the Rate Limit Headers policy, then the Rate Limit Headers policy does not work.

By default, there are no rate limit headers in the response message when the Rate Limit Headers policy is not configured or when your application plan does not have any rate limits.

As an API provider, you can add the Response/Request Content Limits policy to an API product. This policy lets you limit the size of a request to an upstream API as well as the size of a response from an upstream API. Without this policy, the request/response size is unlimited.

This policy is helpful for preventing overloading of:

In a request or in a response, the content-length header is required for 3scale to apply the Response/Request Content Limits policy.

In the Admin Portal, after you add the Response/Request Content Limits policy to a product, click it to specify the limits in bytes. You can specify the request limit, or the response limit, or both. The default value, 0, indicates an unlimited size.

Alternatively, you can add this policy by updating your policy chain configuration file, for example:

{
  "name": "apicast.policy.limits",
  "configuration":
  {
    "request": 100,
    "response": 100
  }
}

The Retry policy sets the number of retry requests to the upstream API. The retry policy is configured per service, so users can enable retries for as few or as many of their services as desired, as well as configure different retry values for different services.

An example of the retry policy JSON is shown below:

{
  "$schema": "http://apicast.io/policy-v1/schema#manifest#",
  "name": "Retry",
  "summary": "Allows retry requests to the upstream",
  "description": "Allows retry requests to the upstream",
  "version": "builtin",
  "configuration": {
    "type": "object",
    "properties": {
      "retries": {
        "description": "Number of retries",
        "type": "integer",
        "minimum": 1,
        "maximum": 10
      }
    }
  }
}

This policy adds role check when used with the OpenID Connect authentication option. This policy verifies realm roles and client roles in the access token issued by Red Hat Single Sign-On (RH-SSO). The realm roles are specified when you want to add role check to every client resource of 3scale.

There are the two types of role checks that the type property specifies in the policy configuration:

It is not possible to configure both checks – blacklist and whitelist in the same policy, but you can add more than one instance of the RH-SSO/Keycloak Role Check policy to the APIcast policy chain.

You can configure a list of scopes via the scopes property of the policy configuration.

Each scope object has the following properties:

The Routing policy allows you to route requests to different target endpoints. You can define target endpoints and then you will be able to route incoming requests from the UI to those using regular expressions.

Liquid Context Debug
JWT Claim Check
Routing
3scale APIcast

Liquid Context Debug
Routing
3scale APIcast
JWT Claim Check

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/accounts"
              }
            ]
          }
        }
      ]
    }
  }

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "header",
                "header_name": "Test-Header",
                "op": "==",
                "value": "123"
              }
            ]
          }
        }
      ]
    }
  }

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "query_arg",
                "query_arg_name": "test_query_arg",
                "op": "==",
                "value": "123"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration that routes to http://example.com when the value of the JWT claim test_claim is 123:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "jwt_claim",
                "jwt_claim_name": "test_claim",
                "op": "==",
                "value": "123"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration that routes to http://example.com when the path of the request is /accounts and when the value of the header Test-Header is 123:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "combine_op": "and",
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/accounts"
              },
              {
                "match": "header",
                "header_name": "Test-Header",
                "op": "==",
                "value": "123"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration that routes to http://example.com when the path of the request is /accounts or when the value of the header Test-Header is 123:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "combine_op": "or",
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/accounts"
              },
              {
                "match": "header",
                "header_name": "Test-Header",
                "op": "==",
                "value": "123"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration with several rules:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://some_upstream.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/accounts"
              }
            ]
          }
        },
        {
          "url": "http://another_upstream.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/users"
              }
            ]
          }
        }
      ]
    }
  }

This configuration routes the request to http://some_upstream.com if the path is /abc, routes the request to http://another_upstream.com if the path is /def, and finally, routes the request to http://default_upstream.com if none of the previous rules evaluated to true:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://some_upstream.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/abc"
              }
            ]
          }
        },
        {
          "url": "http://another_upstream.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/def"
              }
            ]
          }
        },
        {
          "url": "http://default_upstream.com",
          "condition": {
            "operations": []
          }
        }
      ]
    }
  }

This is a configuration that uses !=. It routes to http://example.com when the path is not /accounts:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "!=",
                "value": "/accounts"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration that uses that value to route the request:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "condition": {
            "operations": [
              {
                "match": "header",
                "header_name": "Test-Header",
                "op": "==",
                "value": "{{ my_var }}",
                "value_type": "liquid"
              }
            ]
          }
        }
      ]
    }
  }

This is a configuration that specifies some_host.com as the host of the Host header:

 {
    "name": "routing",
    "version": "builtin",
    "configuration": {
      "rules": [
        {
          "url": "http://example.com",
          "host_header": "some_host.com",
          "condition": {
            "operations": [
              {
                "match": "path",
                "op": "==",
                "value": "/"
              }
            ]
          }
        }
      ]
    }
  }

The SOAP policy matches SOAP action URIs provided in the SOAPAction or Content-Type header of an HTTP request with mapping rules specified in the policy.

Configuration properties

Policy object example

{
  "name": "soap",
  "version": "builtin",
  "configuration": {
    "mapping_rules": [
      {
        "pattern": "http://example.com/soap#request",
        "metric_system_name": "soap",
        "delta": 1
      }
    ]
  }
}

For information on how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

With the TLS Client Certificate Validation policy, APIcast implements a TLS handshake and validates the client certificate against a whitelist. A whitelist contains certificates signed by the Certified Authority (CA) or just plain client certificates. In case of an expired or invalid certificate, the request is rejected and no other policies will be processed.

The client connects to APIcast to send a request and provides a Client Certificate. APIcast verifies the authenticity of the provided certificate in the incoming request according to the policy configuration. APIcast can also be configured to use a client certificate of its own to use it when connecting to the upstream.

You must have access to a 3scale installation. You must wait for all the deployments to finish.

Additionally:

To save your changes, click Update Policy Chain.

You can verify the applied policy by specifying [Your_user_key] in the placeholder.

curl https://api-3scale-apicast-staging.$WILDCARD_DOMAIN\?user_key\=[Your_user_key] -v --cacert ca/certs/ca.crt --cert ca/certs/client.crt --key ca/keys/client.key

curl https://api-3scale-apicast-staging.$WILDCARD_DOMAIN\?user_key\=[Your_user_key] -v --cacert ca/certs/ca.crt --cert ca/certs/server.crt --key ca/keys/server.key

curl https://api-3scale-apicast-staging.$WILDCARD_DOMAIN\?user_key\=[Your_user_key] -v --cacert ca/certs/ca.crt

To save your changes, click Update Policy Chain.

For more information about working with certificates, you can refer to Red Hat Certificate System.

This section provides information about the Transport Layer Security (TLS) Termination policy: concepts, configuration, verification and file removal from the policy.

With the TLS Termination policy, you can configure APIcast to finish TLS requests for each API without using a single certificate for all APIs. APIcast pulls the configuration setting before establishing a connection to the client; in this way, APIcast uses the certificates from the policy and makes the TLS terminate. This policy works with these sources:

By default, this policy is not enabled in policy chains.

Follow this procedure:

Additionally:

To save your changes, click Update Policy Chain.

You can test in the command line if the policy works with the following command:

curl “${public_URL}:${port}/?user_key=${user_key}" --cacert ${path_to_certificate}/ca.pem -v

where:

To remove a certificate:

To save your changes, click Update Policy Chain.

The Upstream policy allows you to parse the Host request header using regular expressions and replace the upstream URL defined in the Private Base URL with a different URL.

For Example:

A policy with a regex /foo, and URL field newexample.com would replace the URL https://www.example.com/foo/123/ with newexample.com

Policy chain reference:

Policy object example

{
  "name": "upstream",
  "version": "builtin",
  "configuration": {
    "rules": [
      {
        "regex": "^/v1/.*",
        "url": "https://api-v1.example.com",

      }
    ]
  }
}

For information on how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

The Upstream Connection policy allows you to change the default values of the following directives, for each API, depending on how you have configured the API backend server in your 3scale installation:

To configure the Upstream Connection policy:

Follow this procedure:

To save your changes, click Update Policy Chain.

With the Upstream Mutual TLS policy, you can establish and validate mutual TLS connections between APIcast and upstream APIs based on the certificates set in the configuration.

When the verify field is enabled, the policy also verifies the server certificate from the upstream APIs. The ca_certificates contains a Privacy Enhanced Mail (PEM) formatted certificate, including the -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- that the APIcast uses to validate the server.

To configure Upstream Mutual TLS in your policy chain, you need to have access to a 3scale installation.

To promote your changes:

v# represents the version number of the configuration to be promoted.

{
  "name": "apicast.policy.upstream_mtls",
  "configuration": {
      "certificate": "/secrets/client.cer",
      "certificate_type": "path",
      "certificate_key": "/secrets/client.key",
      "certificate_key_type": "path"
  }
}

{
  "name": "apicast.policy.upstream_mtls",
  "configuration": {
    "certificate_type": "embedded",
    "certificate_key_type": "embedded",
    "certificate": "data:application/pkix-cert;name=client.cer;base64,XXXXXXXXXXX",
    "certificate_key": "data:application/x-iwork-keynote-sffkey;name=client.key;base64,XXXXXXXX"
  }
}

For more details about the additional fields, ca_certificates and verify for Upstream Mutual TLS, policy config schema.

The URL Rewriting policy allows you to modify the path of a request and the query string.

When combined with the 3scale APIcast policy, if the URL Rewriting policy is placed before the APIcast policy in the policy chain, the APIcast mapping rules will apply to the modified path. If the URL Rewriting policy is placed after APIcast in the policy chain, then the mapping rules will apply to the original path.

The policy supports the following two sets of operations:

{
  "name": "url_rewriting",
  "version": "builtin",
  "configuration": {
    "query_args_commands": [
      {
        "op": "add",
        "arg": "addarg",
        "value_type": "plain",
        "value": "addvalue"
      },
      {
        "op": "delete",
        "arg": "user_key",
        "value_type": "plain",
        "value": "any"
      },
      {
        "op": "push",
        "arg": "pusharg",
        "value_type": "plain",
        "value": "pushvalue"
      },
      {
        "op": "set",
        "arg": "setarg",
        "value_type": "plain",
        "value": "setvalue"
      }
    ],
    "commands": [
      {
        "op": "sub",
        "regex": "^/api/v\\d+/",
        "replace": "/internal/",
        "options": "i"
      }
    ]
  }

The original request URI that is sent to the APIcast:

https://api.example.com/api/v1/products/123/details?user_key=abc123secret&pusharg=first&setarg=original

The URI that APIcast sends to the API backend after applying the URL rewriting:

https://api-backend.example.com/internal/products/123/details?pusharg=first&pusharg=pushvalue&setarg=setvalue

The following transformations are applied:

For information on how to configure policies, see the Creating a policy chain in 3scale API Management section of the documentation.

The URL Rewriting with Captures policy is an alternative to the URL Rewriting policy and allows rewriting the URL of the API request before passing it to the API backend.

The URL Rewriting with Captures policy retrieves arguments in the URL and uses their values in the rewritten URL.

The policy supports the transformations configuration parameter. It is a list of objects that describe which transformations are applied to the request URL. Each tranformation object consist of two properties:

The query parameters of the original URL are merged with the query parameters specified in the template.

Example

The URL Rewriting with Captures policy is configured as follows:

{
  "name": "rewrite_url_captures",
  "version": "builtin",
  "configuration": {
    "transformations": [
      {
        "match_rule": "/api/v1/products/{productId}/details",
        "template": "/internal/products/details?id={productId}&extraparam=anyvalue"
      }
    ]
  }
}

The original request URI that is sent to the APIcast:

https://api.example.com/api/v1/products/123/details?user_key=abc123secret

The URI that APIcast sends to the API backend after applying the URL rewriting:

https://api-backend.example.com/internal/products/details?user_key=abc123secret&extraparam=anyvalue&id=123

The WebSocket policy enables WebSocket protocol connections to upstream APIs. If you plan to enable the WebSocket protocol, consider the following:

For a given upstream API for which you enable WebSocket connections, you can define its backends as http[s] or ws[s].

If you add the WebSocket policy to a policy chain, ensure that it is before the 3scale API Management APIcast policy.

The 3scale API gateway, or APIcast, uses the NGINX proxy web server to apply policies. When APIcast receives a request from an API consumer, APIcast processes the request in an ordered series of NGINX phases. In each NGINX phase, APIcast can modify the original request by applying these policies:

If the same policy is in an upstream API policy chain and in the global policy chain, the policy configuration in the upstream API policy chain has precedence.

After APIcast performs the processing required in all NGINX phases, APIcast sends the result in a request to the upstream API. Consequently, to achieve the desired behavior, it is important to understand the order in which NGINX phases process policies because processing can modify the API consumer request.

Examples of NGINX phases that perform processing that is not affected by policy order:

Policies can share data by means of a context object. Policies can read from and modify the context object in each phase.

The order in which NGINX executes policy functions depends on the following:

To obtain the desired behavior, you must correctly specify the policy chain order because the result of applying a policy can vary according to its place in a policy chain. The following diagram shows an example of the order in which NGINX applies policies.

In the previous figure, policy A is first in the policy chain. However, NGINX processes a function in policy B first because that function is related to NGINX’s first phase, the rewrite phase.

Now consider a product’s policy chain that contains policy A and then policy B with these functions:

The following figure shows the order in which NGINX runs the product’s policy functions.

When APIcast receives a request for access to the upstream API exposed by this product, APIcast checks the product’s policy chain and runs the functions as described in the following table:

In this example, policy A is first in the policy chain but a function in policy B is the first function that NGINX runs. This is because policy B specifies a function B1 that NGINX processes in the rewrite phase, which comes before the other phases.

For another example, consider this policy chain:

The URL Rewriting policy modifies a request’s target path. APIcast runs the URL Rewriting function in the rewrite phase. The 3scale APIcast policy defines a function that APIcast runs in the rewrite phase as well as functions that APIcast runs in three other phases. When the URL Rewriting policy is first, the 3scale APIcast policy applies mapping rules to the rewritten path. If the 3scale APIcast policy is first and the URL Rewriting policy is second, the 3scale APIcast policy applies mapping rules to the original path.

Modify a product’s policy chain in the 3scale Admin Portal as part of your APIcast gateway configuration.

If you are using a native deployment of APIcast, you can create a JSON configuration file to control your policy chain outside.

A JSON configuration file policy chain contains a JSON array composed of the following information:

The following is an example policy chain for a custom policy sample_policy_1 and the API introspection standard policy token_introspection:

{
  "services":[
    {
      "id":1,
      "proxy":{
        "policy_chain":[
          {
            "name":"sample_policy_1", "version": "1.0",
            "configuration":{
              "sample_config_param_1":["value_1"],
              "sample_config_param_2":["value_2"]
            }
          },
          {
            "name": "token_introspection", "version": "builtin",
            "configuration": {
              introspection_url:["https://tokenauthorityexample.com"],
              client_id:["exampleName"],
              client_secret:["secretexamplekey123"]
          },
          {
             "name": "apicast", "version": "builtin",
          }
        ]
      }
    }
  ]
}

All policy chains must include the builtin policy apicast. Where you place the apicast policy in the policy chain affects policy behavior.

The following table lists the main NGINX phases with the standard policies that define functions that NGINX runs in that phase. The table lists the phases in the order in which NGINX processes them.

A policy chain can contain more than one policy that NGINX processes in a particular phase. In this situation, ensure that the order of the policies in the chain is the correct order for processing the API request to obtain the desired result. The table lists the policies in alphabetical order.

The following table lists the standard policies and the NGINX phase or phases that run that policy’s function or functions. Use this table to correctly order policies in a policy chain to produce the correct request for the upstream API.

The following examples show how to use curl commands and the jq tool to read and update the proxy policies chain. Replace the placeholder values {admin_portal_url}, {service_id}, and {access_token} with values that represent your environment.

You can create custom APIcast policies entirely or modify the standard policies.

To create custom policies, you must understand the following:

To add custom policies to your 3scale API Management instance, see Injecting custom policies with the 3scale API Management operator.

You can add custom policies to APIcast on OpenShift Container Platform (OCP) by fetching APIcast images containing your custom policies from the Integrated OpenShift Container Platform registry.

You can add an external Lua dependency to a custom policy so that APIcast can use a Lua library that is not yet in your 3scale image.

The procedure here shows you how to do this by using an example of a custom policy that transforms a response body from JSON to XML. The example custom policy requires the xml2lua XML parser, which is written in Lua. The complete example shows a short cut for building and testing but you cannot deploy your custom policy by following only the example procedure. To deploy a custom policy that has an external Lua dependency, you must perform the steps in this procedure as well as the procedure for Adding custom policies to 3scale API Management in another OpenShift Container Platform.