Datomic Documentation
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Configuring Logging

Transactor Logging

The Datomic transactor logs via logback. Datomic includes a sample logback configuration file suitable for development at bin/logback.xml. This sample logback configuration is set up by default to log to the directory specified by the log-dir transactor property (defaults to log/ within Datomic distribution).

Logback is open source and highly configurable. It includes built-in appenders that can send logs via email or to a SQL database, and you can write a custom appender for arbitrary integrations.

Transactor S3 Log Rotation

The transactor can automatically migrate its logs to S3. When you set the transactor property aws-s3-log-bucket-id, the transactor will copy log files found in the directory configured by setting the transactor property log-dir. If you need more flexible access to logs, you should configure or implement a logback appender.

Peer Logging

The Datomic peer library uses slf4j for logging, so Peers can be configured to output logs via a variety of standard Java logging libraries, including logback, java.util.logging and log4j by:

  • Including the appropriate slf4j JAR on the classpath
  • (Optionally) adding corresponding configuration files

The following sections show how to configure Peer logging in Maven and Leiningen. If you do not configure logging for your project, the Datomic peer library will not log.

Peer Logging with logback

If you choose to use logback on the peer, you can use the transactor's bin/logback.xml file as a starting point for your configuration.

Maven

For Maven, add the following to the dependencies section of your pom.xml, replacing DATOMIC_VERSION, as described above. 

<dependency>
  <groupId>com.datomic</groupId>
  <artifactId>peer</artifactId>
  <version>DATOMIC_VERSION</version>
  <exclusions>
    <exclusion>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
    </exclusion>
    <exclusion>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-nop</artifactId>
    </exclusion>
  </exclusions>
</dependency>
<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
  <version>1.0.1</version>
</dependency>

Leiningen

For leiningen, add the following to the dependencies section of your project.clj, replacing DATOMIC_VERSION, as described above. 

[com.datomic/peer "DATOMIC_VERSION"
 :exclusions [org.slf4j/slf4j-nop org.slf4j/slf4j-log4j12]]
[ch.qos.logback/logback-classic "1.0.1"]

Peer Logging with java.util.logging

Maven

For Maven, add the following to the dependencies section of your pom.xml, replacing DATOMIC_VERSION, as described above. 

<dependency>
  <groupId>com.datomic</groupId>
  <artifactId>peer</artifactId>
  <version>DATOMIC_VERSION</version>
  <exclusions>
    <exclusion>
      <groupId>org.slf4j</groupId>
      <artifactId>jul-to-slf4j</artifactId>
    </exclusion>
    <exclusion>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-nop</artifactId>
    </exclusion>
  <exclusions>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-jdk14</artifactId>
  <version>1.6.4</version>
</dependency>

Leiningen

For leiningen, add the following to the dependencies section of your project.clj, replacing DATOMIC_VERSION, as described above. 

[com.datomic/peer "DATOMIC_VERSION"
 :exclusions [org.slf4j/jul-to-slf4j org.slf4j/slf4j-nop]]
[org.slf4j/slf4j-jdk14 "1.6.4"]

Peer Logging with log4j

Maven

For Maven, add the following to the dependencies section of your pom.xml, replacing DATOMIC_VERSION, as described above. 

<dependency>
  <groupId>com.datomic</groupId>
  <artifactId>peer</artifactId>
  <version>DATOMIC_VERSION</version>
  <exclusions>
    <exclusion>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-nop</artifactId>
    </exclusion>
    <exclusion>
     <groupId>org.slf4j</groupId>
     <artifactId>log4j-over-slf4j</artifactId>
    </exclusion>
  </exclusions>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
  <version>1.6.4</version>
</dependency>

Leiningen

For Leiningen, add the following to the dependencies section of your project.clj, replacing DATOMIC_VERSION, as described above. 

[com.datomic/peer "DATOMIC_VERSION"
 :exclusions [org.slf4j/slf4j-nop org.slf4j/log4j-over-slf4j]]
[org.slf4j/slf4j-log4j12 "1.6.4"]