Chapter 7. APIcast environment variables

download PDF

APIcast environment variables allow you to modify behavior for APIcast. The following values are supported environment variables:

  • Unsupported or deprecated environment variables are not listed
  • Some environment variable functionality may have moved to APIcast policies

all_proxy, ALL_PROXY

Default: no value Value: string Example: http://forward-proxy:80

Defines a HTTP proxy to be used for connecting to services if a protocol-specific proxy is not specified. Authentication is not supported.


Default: no value

Value: positive integer

Allows access log writes to be included in chunks of bytes. The result is fewer system calls, which improves the performance of the gateway.


Default: stdout

Defines the file that will store the access logs.


Values: strict | resilient

Default: strict

Deprecated: Use the Caching policy instead.

Defines how the authorization cache behaves when backend is unavailable. Strict will remove cached application when backend is unavailable. Resilient will do so only on getting authorization denied from backend.


Default: 1m

Value: string

When the response is selected to be cached in the system, the value of this variable indicates the maximum time to be cached. If the cache-control header is not set, the time to be cached will be the defined one.

The format for this value is defined by the proxy_cache_valid NGINX directive.

This parameter is only used by the APIs that are using a content caching policy and the request is eligible to be cached.


Default: 200, 302

Value: string

When the response code from upstream matches one of the status codes defined in this environment variable, the response content is cached in NGINX. The caching time depends on one of these values: headers cache time value, or the maximum time defined by the APICAST_CACHE_MAX_TIME environment variable.

This parameter is only used by the APIs that are using a content caching policy and the request is eligible to be cached.


Values: a number

Default: 0

Specifies the interval (in seconds) that the configuration will be stored for. The value should be set to 0 (not compatible with boot value of APICAST_CONFIGURATION_LOADER) or more than 60. For example, if APICAST_CONFIGURATION_CACHE is set to 120, the gateway will reload the configuration from the API manager every 2 minutes (120 seconds). A value < 0 disables reloading.


Values: boot | lazy

Default: lazy

Defines how to load the configuration. Boot will request the configuration to the API manager when the gateway starts. Lazy will load it on demand for each incoming request (to guarantee a complete refresh on each request APICAST_CONFIGURATION_CACHE should be 0).


Deprecated: Use policies instead.

Defines the name of the Lua module that implements custom logic overriding the existing APIcast logic.



Value: string[:]

Example: production:cloud-hosted

APIcast should load a list of environments (or paths), separated by colons (:). This list can be used instead of -e or --environment parameter on the CLI and for example stored in the container image as default environment. Any value passed on the CLI overrides this variable.


Default: false

Value: boolean

Example: "true"

Enables additional information on Prometheus metrics. The following metrics have the service_id and service_system_name labels which provide more in-depth details about APIcast:

  • total_response_time_seconds
  • upstream_response_time_seconds
  • upstream_status


Default: no value

Path to a file with X.509 certificate in the PEM format for HTTPS.


Default: no value

Path to a file with the X.509 certificate secret key in the PEM format.


Default: no value

Controls on which port APIcast should start listening for HTTPS connections. If this clashes with HTTP port it will be used only for HTTPS.


Default: 1

Values: positive integers.

Defines the maximum length of the client certificate chain. If this parameter has 1 as its value, it is possible to include an additional certificate in the client certificate chain. For example, root certificate authority.



  • true or 1 for true
  • false, 0 or empty for false

Default: false

This option can be used when there are many services configured. However, its performance depends on additional factors, for example, the number of services, the latency between APIcast and the 3scale Admin Portal, and the Time To Live (TTL) of the configuration.

By default, APIcast loads all the services each time it downloads its configuration from the Admin Portal. When this option is enabled, the configurations uses lazy loading. APIcast will only load the ones configured for the host specified in the host header of the request.



Default: stderr

Defines the file that contains the OpenResty error log. The file is used by bin/apicast in the error_log directive. The file path can be either absolute, or relative to the APIcast prefix directory. Note that the default prefix directory is APIcast. Refer to NGINX documentation for more information.


Values: debug | info | notice | warn | error | crit | alert | emerg

Default: warn

Specifies the log level for the OpenResty logs.



  • disabled: completely disabled, just listens on the port
  • status: only the /status/ endpoints enabled for health checks
  • debug: full API is open

The Management API is powerful and can control the APIcast configuration. You should enable the debug level only for debugging.


Default: apicast

Deprecated: Use policies instead.

Specifies the name of the main Lua module that implements the API gateway logic. Custom modules can override the functionality of the default apicast.lua module. See an example of how to use modules.


Values: debug | info | notice | warn | error | crit | alert | emerg

Default: err

Allows to set the log level for the logs related to OpenID Connect integration.



  • true or 1 for true
  • false, 0 or empty for false

When this parameter is set to true, the gateway will use path-based routing in addition to the default host-based routing. The API request will be routed to the first service that has a matching mapping rule, from the list of services for which the value of the Host header of the request matches the Public Base URL.



  • true or 1 for true
  • false, 0 or empty for false

When this parameter is set to true, the gateway uses path-based routing and will not fallback to the default host-based routing. The API request is routed to the first service that has a matching mapping rule, from the list of services for which the value of the Host header of the request matches the Public Base URL.

This parameter has precedence over APICAST_PATH_ROUTING. If APICAST_PATH_ROUTING_ONLY is enabled, APIcast will only do path-based routing regardless of the value of APICAST_PATH_ROUTING.


Default: APICAST_DIR/policies

Value: string[:]

Example: ~/apicast/policies:$PWD/policies

A colon (:) separated list of paths where APIcast should look for policies. It can be used to first load policies from a development directory or to load examples.



Value: string

Example: /home/apicast/my_certificate.crt

The path to the client SSL certificate that APIcast will use when connecting with the upstream. Notice that this certificate will be used for all the services in the configuration.



Value: string

Example: /home/apicast/my_certificate.key

The path to the key of the client SSL certificate.



Value: string

Example: /home/apicast/passwords.txt

Path to a file with passphrases for the SSL cert keys specified with APICAST_PROXY_HTTPS_CERTIFICATE_KEY.


Default: on


  • on: reuses SSL sessions.
  • off: does not reuse SSL sessions.


Default: 0

Value: integer >= 0

Experimental: Under extreme load might have unpredictable performance and lose reports.

Value greater than 0 is going to enable out-of-band reporting to backend. This is a new experimental feature for increasing performance. Client won’t see the backend latency and everything will be processed asynchronously. This value determines how many asynchronous reports can be running simultaneously before the client is throttled by adding latency.



  • true or 1 for true
  • false, 0 or empty for false

Default: <empty> (false)

When set to true, APIcast will log the response code of the response returned by the API backend in 3scale. For more information, see Setting up and evaluating the 3scale response codes log for your API.


Values: integer >= 0

Default: 1000

Specifies the number of services that APIcast can store in the internal cache. A high value has a performance impact because Lua’s lru cache will initialize all the entries.


Replace ${ID} with the actual Service ID. The value should be the configuration version you can see in the configuration history on the Admin Portal. Setting it to a particular version will prevent it from auto-updating and will always use that version.


Value: a comma-separated list of service IDs

The APICAST_SERVICES_LIST environment variable is used to filter the services you configure in the 3scale API Manager. This only applies the configuration for specific services in the gateway, discarding those service identifiers that are not specified in the list. You can find service identifiers for your product in the Admin Portal under Products > [Your_product_name] > Overview, then see Configuration, Methods and Settings and the ID for API calls.


Value: a PCRE (Perl Compatible Regular Expression) such as .*

Filters the services configured in the 3scale API Manager.

This filter matches with the Public Base URL, either staging or production. Services that do not match the filter are discarded. If the regular expression cannot be compiled, no services are loaded.


If a service does not match but is included in the section called “APICAST_SERVICES_LIST, the service will not be discarded.

Example 7.1. A Regexp filter applied to backend endpoints

The Regexp filter http://.* is applied to the following backend endpoints:

In this case, 1 and 3 are configured in APIcast and 2 and 4 are discarded.


Values: error | timeout | invalid_header | http_500 | http_502 | http_503 | http_504 | http_403 | http_404 | http_429 | non_idempotent | off


This is only used when the retry policy is configured and specifies when a request to the upstream API should be retried. It accepts the same values as Nginx’s PROXY_NEXT_UPSTREAM Module.


Default: auto

Values: number | auto

This is the value that will be used in the nginx worker_processes directive. By default, APIcast uses auto, except for the development environment where 1 is used.


URI that overrides backend endpoint from the configuration. Useful when deploying outside OpenShift deployed AMP. Example:


Default: 75 Value: positive integers Example: 1

This parameter sets a timeout during which a keep-alive client connection will stay open on the server side. The zero value disables keep-alive client connections.

By default, the gateway keeps HTTP_KEEPALIVE_TIMEOUT disabled. This configuration allows the use of the keepalive timeout from NGINX whose default value is 75 seconds.

http_proxy, HTTP_PROXY

Default: no value Value: string Example: http://forward-proxy:80

Defines a HTTP proxy to be used for connecting to HTTP services. Authentication is not supported.

https_proxy, HTTPS_PROXY

Default: no value Value: string Example: https://forward-proxy:443

Defines a HTTP proxy to be used for connecting to HTTPS services. Authentication is not supported.

no_proxy, NO_PROXY

Default: no value Value: string\[,<string>\]; *Example: foo,,

Defines a comma-separated list of hostnames and domain names for which the requests should not be proxied. Setting to a single * character, which matches all hosts, effectively disables the proxy.



  • 0, false: disable peer verification
  • 1, true: enable peer verification

Controls the OpenSSL Peer Verification. It is off by default, because OpenSSL can’t use system certificate store. It requires custom certificate bundle and adding it to trusted certificates.

It is recommended to use and point to to certificate bundle generated by export-builtin-trusted-certs.


This environment variable is used to determine the config file for the opentracing tracer, if OPENTRACING_TRACER is not set, this variable will be ignored.

Each tracer has a default configuration file: * jaeger: conf.d/opentracing/jaeger.example.json

You can choose to mount a different configuration than the provided by default by setting the file path using this variable.

Example: /tmp/jaeger/jaeger.json


Default: uber-trace-id

This environment variable controls the HTTP header used for forwarding opentracing information, this HTTP header will be forwarded to upstream servers.


Example: jaeger

This environment variable controls which tracing library will be loaded, right now, there’s only one opentracing tracer available, jaeger.

If empty, opentracing support will be disabled.


Allows to specify a custom DNS resolver that will be used by OpenResty. If the RESOLVER parameter is empty, the DNS resolver will be autodiscovered.


Path to the JSON file with the configuration for the gateway. You must provide either THREESCALE_PORTAL_ENDPOINT or THREESCALE_CONFIG_FILE for the gateway to run successfully. From these two environment variables, THREESCALE_CONFIG_FILE takes precedence

To build the file with the configuration for the gateway, you have two alternatives depending on the number of services:

  • Option 1. Download the configuration from the Admin Portal using the URL:


    Consider the following:

    • The endpoint has limitations once 20 services have been exceeded.
    • You can see an example in:
  • Option 2. Use the available 3scale API endpoints:

    • Either Proxy Config Show or Proxy Config Show Latest.
    • Then, iterate over the services to build a configuration file. For this step, use the available 3scale API endpoints, or the equivalent 3scale toolbox commands.

When you deploy the gateway using a container image:

  1. Configure the file to the image as a read-only volume.
  2. Specify the path that indicates where you have mounted the volume.

You can find sample configuration files in examples folder.


Values: staging | production

Default: production

The value of this environment variable defines the environment from which the configuration will be downloaded from; this is either 3scale staging or production, when using new APIcast.

The value will also be used in the header X-3scale-User-Agent in the authorize/report requests made to 3scale Service Management API. It is used by 3scale solely for statistics.


URI that includes your password and portal endpoint in the following format:



  • <password> can be either the provider key or an access token for the 3scale Account Management API.
  • <admin-portal-domain> is the URL address to log into the 3scale Admin Portal.


When the THREESCALE_PORTAL_ENDPOINT environment variable is provided, the gateway downloads the configuration from 3scale on initializing. The configuration includes all the settings provided on the Integration page of the APIs.

You can also use this environment variable to create a single gateway with the Master Admin Portal.

It is required to provide either THREESCALE_PORTAL_ENDPOINT or THREESCALE_CONFIG_FILE (takes precedence) for the gateway to run successfully.

Red Hat logoGithubRedditYoutubeTwitter


Try, buy, & sell


About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

© 2024 Red Hat, Inc.