Chapter 37. Log
Only producer is supported
The Log component logs message exchanges to the underlying logging mechanism.
Camel uses SLF4J which allows you to configure logging via, among others:
- Log4j
- Logback
- Java Util Logging
37.1. URI format
log:loggingCategory[?options]
Where loggingCategory is the name of the logging category to use. You can append query options to the URI in the following format,
?option=value&option=value&…
Using Logger instance from the Registry
If there’s single instance of org.slf4j.Logger found in the Registry, the loggingCategory is no longer used to create logger instance. The registered instance is used instead. Also it is possible to reference particular Logger instance using ?logger=#myLogger URI parameter. Eventually, if there’s no registered and URI logger parameter, the logger instance is created using loggingCategory.
For example, a log endpoint typically specifies the logging level using the level option, as follows:
log:org.apache.camel.example?level=DEBUG
The default logger logs every exchange (regular logging). But Camel also ships with the Throughput logger, which is used whenever the groupSize option is specified.
Also a log in the DSL
There is also a log directly in the DSL, but it has a different purpose. Its meant for lightweight and human logs. See more details at LogEIP.
37.2. Configuring Options
Camel components are configured on two separate levels:
- component level
- endpoint level
37.2.1. Configuring Component Options
The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.
Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.
Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.
37.2.2. Configuring Endpoint Options
Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.
Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.
A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.
The following two sections lists all the options, firstly for the component followed by the endpoint.
37.3. Component Options
The Log component supports 3 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| lazyStartProducer (producer) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean |
| autowiredEnabled (advanced) | Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. | true | boolean |
| exchangeFormatter (advanced) | Autowired Sets a custom ExchangeFormatter to convert the Exchange to a String suitable for logging. If not specified, we default to DefaultExchangeFormatter. | ExchangeFormatter |
37.4. Endpoint Options
The Log endpoint is configured using URI syntax:
log:loggerName
with the following path and query parameters:
37.4.1. Path Parameters (1 parameters)
| Name | Description | Default | Type |
|---|---|---|---|
| loggerName (producer) | Required Name of the logging category to use. | String |
37.4.2. Query Parameters (27 parameters)
| Name | Description | Default | Type |
|---|---|---|---|
| groupActiveOnly (producer) | If true, will hide stats when no new messages have been received for a time interval, if false, show stats regardless of message traffic. | true | Boolean |
| groupDelay (producer) | Set the initial delay for stats (in millis). | Long | |
| groupInterval (producer) | If specified will group message stats by this time interval (in millis). | Long | |
| groupSize (producer) | An integer that specifies a group size for throughput logging. | Integer | |
| lazyStartProducer (producer) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean |
| level (producer) | Logging level to use. The default value is INFO. Enum values:
| INFO | String |
| logMask (producer) | If true, mask sensitive information like password or passphrase in the log. | Boolean | |
| marker (producer) | An optional Marker name to use. | String | |
| exchangeFormatter (advanced) | To use a custom exchange formatter. | ExchangeFormatter | |
| maxChars (formatting) | Limits the number of characters logged per line. | 10000 | int |
| multiline (formatting) | If enabled then each information is outputted on a newline. | false | boolean |
| showAll (formatting) | Quick option for turning all options on. (multiline, maxChars has to be manually set if to be used). | false | boolean |
| showAllProperties (formatting) | Show all of the exchange properties (both internal and custom). | false | boolean |
| showBody (formatting) | Show the message body. | true | boolean |
| showBodyType (formatting) | Show the body Java type. | true | boolean |
| showCaughtException (formatting) | If the exchange has a caught exception, show the exception message (no stack trace). A caught exception is stored as a property on the exchange (using the key org.apache.camel.Exchange#EXCEPTION_CAUGHT) and for instance a doCatch can catch exceptions. | false | boolean |
| showException (formatting) | If the exchange has an exception, show the exception message (no stacktrace). | false | boolean |
| showExchangeId (formatting) | Show the unique exchange ID. | false | boolean |
| showExchangePattern (formatting) | Shows the Message Exchange Pattern (or MEP for short). | true | boolean |
| showFiles (formatting) | If enabled Camel will output files. | false | boolean |
| showFuture (formatting) | If enabled Camel will on Future objects wait for it to complete to obtain the payload to be logged. | false | boolean |
| showHeaders (formatting) | Show the message headers. | false | boolean |
| showProperties (formatting) | Show the exchange properties (only custom). Use showAllProperties to show both internal and custom properties. | false | boolean |
| showStackTrace (formatting) | Show the stack trace, if an exchange has an exception. Only effective if one of showAll, showException or showCaughtException are enabled. | false | boolean |
| showStreams (formatting) | Whether Camel should show stream bodies or not (eg such as java.io.InputStream). Beware if you enable this option then you may not be able later to access the message body as the stream have already been read by this logger. To remedy this you will have to use Stream Caching. | false | boolean |
| skipBodyLineSeparator (formatting) | Whether to skip line separators when logging the message body. This allows to log the message body in one line, setting this option to false will preserve any line separators from the body, which then will log the body as is. | true | boolean |
| style (formatting) | Sets the outputs style to use. Enum values:
| Default | OutputStyle |
37.5. Regular logger sample
In the route below we log the incoming orders at DEBUG level before the order is processed:
from("activemq:orders").to("log:com.mycompany.order?level=DEBUG").to("bean:processOrder");Or using Spring XML to define the route:
<route> <from uri="activemq:orders"/> <to uri="log:com.mycompany.order?level=DEBUG"/> <to uri="bean:processOrder"/> </route>
37.6. Regular logger with formatter sample
In the route below we log the incoming orders at INFO level before the order is processed.
from("activemq:orders").
to("log:com.mycompany.order?showAll=true&multiline=true").to("bean:processOrder");37.7. Throughput logger with groupSize sample
In the route below we log the throughput of the incoming orders at DEBUG level grouped by 10 messages.
from("activemq:orders").
to("log:com.mycompany.order?level=DEBUG&groupSize=10").to("bean:processOrder");37.8. Throughput logger with groupInterval sample
This route will result in message stats logged every 10s, with an initial 60s delay and stats should be displayed even if there isn’t any message traffic.
from("activemq:orders").
to("log:com.mycompany.order?level=DEBUG&groupInterval=10000&groupDelay=60000&groupActiveOnly=false").to("bean:processOrder");The following will be logged:
"Received: 1000 new messages, with total 2000 so far. Last group took: 10000 millis which is: 100 messages per second. average: 100"
37.9. Masking sensitive information like password
You can enable security masking for logging by setting logMask flag to true. Note that this option also affects Log EIP.
To enable mask in Java DSL at CamelContext level:
camelContext.setLogMask(true);
And in XML:
<camelContext logMask="true">
You can also turn it on|off at endpoint level. To enable mask in Java DSL at endpoint level, add logMask=true option in the URI for the log endpoint:
from("direct:start").to("log:foo?logMask=true");And in XML:
<route> <from uri="direct:foo"/> <to uri="log:foo?logMask=true"/> </route>
org.apache.camel.support.processor.DefaultMaskingFormatter is used for the masking by default. If you want to use a custom masking formatter, put it into registry with the name CamelCustomLogMask. Note that the masking formatter must implement org.apache.camel.spi.MaskingFormatter.
37.10. Full customization of the logging output
With the options outlined in the section, you can control much of the output of the logger. However, log lines will always follow this structure:
Exchange[Id:ID-machine-local-50656-1234567901234-1-2, ExchangePattern:InOut,
Properties:{CamelToEndpoint=log://org.apache.camel.component.log.TEST?showAll=true,
CamelCreatedTimestamp=Thu Mar 28 00:00:00 WET 2013},
Headers:{breadcrumbId=ID-machine-local-50656-1234567901234-1-1}, BodyType:String, Body:Hello World, Out: null]This format is unsuitable in some cases, perhaps because you need to…
- Filter the headers and properties that are printed, to strike a balance between insight and verbosity.
- Adjust the log message to whatever you deem most readable.
- Tailor log messages for digestion by log mining systems, e.g. Splunk.
- Print specific body types differently.
Whenever you require absolute customization, you can create a class that implements the interface. Within the format(Exchange) method you have access to the full Exchange, so you can select and extract the precise information you need, format it in a custom manner and return it. The return value will become the final log message.
You can have the Log component pick up your custom ExchangeFormatter in either of two ways:
Explicitly instantiating the LogComponent in your Registry:
<bean name="log" class="org.apache.camel.component.log.LogComponent"> <property name="exchangeFormatter" ref="myCustomFormatter" /> </bean>
37.10.1. Convention over configuration
Simply by registering a bean with the name logFormatter; the Log Component is intelligent enough to pick it up automatically.
<bean name="logFormatter" class="com.xyz.MyCustomExchangeFormatter" />
The ExchangeFormatter gets applied to all Log endpoints within that Camel Context. If you need different ExchangeFormatters for different endpoints, just instantiate the LogComponent as many times as needed, and use the relevant bean name as the endpoint prefix.
When using a custom log formatter, you can specify parameters in the log uri, which gets configured on the custom log formatter. Though when you do that you should define the "logFormatter" as prototype scoped so its not shared if you have different parameters, for example,
<bean name="logFormatter" class="com.xyz.MyCustomExchangeFormatter" scope="prototype"/>
And then we can have Camel routes using the log uri with different options:
<to uri="log:foo?param1=foo&param2=100"/> <to uri="log:bar?param1=bar&param2=200"/>
37.11. Spring Boot Auto-Configuration
When using log with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:
<dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-log-starter</artifactId> </dependency>
The component supports 4 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| camel.component.log.autowired-enabled | Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. | true | Boolean |
| camel.component.log.enabled | Whether to enable auto configuration of the log component. This is enabled by default. | Boolean | |
| camel.component.log.exchange-formatter | Sets a custom ExchangeFormatter to convert the Exchange to a String suitable for logging. If not specified, we default to DefaultExchangeFormatter. The option is a org.apache.camel.spi.ExchangeFormatter type. | ExchangeFormatter | |
| camel.component.log.lazy-start-producer | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | Boolean |
