Collecting Application Logs Using OTEL Java Agent

You can directly send your application logs to SigNoz using Java Agent provided by OpenTelemetry. In this documentation, we will run a sample Java application with the OpenTelemetry Java agent to send logs to SigNoz.

For collecting logs, download the Java agent from here.

To send logs from a Java application, you will need to add the agent and set the appropriate environment variables.

OTEL_LOGS_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443" \
OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>" \
  OTEL_RESOURCE_ATTRIBUTES=service.name=<app_name> \
java -javaagent:/path/opentelemetry-javaagent.jar -jar <myapp>.jar

Replace <your-ingestion-key> with your SigNoz Cloud ingestion key
Set the <region> to match your SigNoz Cloud region

OTEL_LOGS_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT="http://<IP of SigNoz Backend>:4317" \
OTEL_RESOURCE_ATTRIBUTES=service.name=<app_name> \
java -javaagent:/path/opentelemetry-javaagent.jar -jar <myapp>.jar

Replace <IP of SigNoz Backend> with the IP address or hostname of your SigNoz backend.
For local setups, use 0.0.0.0 if SigNoz runs on the same host.

Settings for Appender Instrumentation

You can use appender settings by passing them as arguments in the -D<property>=<value> format.

Example:

-Dotel.instrumentation.logback-appender.experimental-log-attributes=true

Logback Configuration

Logback Documentation

System Property	Type	Default	Description
`otel.instrumentation.logback-appender.experimental-log-attributes`	Boolean	`false`	Capture experimental log attributes like `thread.name` and `thread.id`.
`otel.instrumentation.logback-appender.experimental.capture-code-attributes`	Boolean	`false`	Capture source code attributes. May impact performance.
`otel.instrumentation.logback-appender.experimental.capture-marker-attribute`	Boolean	`false`	Capture Logback markers as attributes.
`otel.instrumentation.logback-appender.experimental.capture-key-value-pair-attributes`	Boolean	`false`	Capture Logback key-value pairs as attributes.
`otel.instrumentation.logback-appender.experimental.capture-logger-context-attributes`	Boolean	`false`	Capture Logback logger context properties as attributes.
`otel.instrumentation.logback-appender.experimental.capture-mdc-attributes`	String	NA	Comma-separated list of MDC attributes to capture. Use `*` to capture all attributes.

Log4j Configuration

Log4j Documentation

System Property	Type	Default	Description
`otel.instrumentation.log4j-appender.experimental-log-attributes`	Boolean	`false`	Capture experimental log attributes like `thread.name` and `thread.id`.
`otel.instrumentation.log4j-appender.experimental.capture-map-message-attributes`	Boolean	`false`	Capture `MapMessage` attributes.
`otel.instrumentation.log4j-appender.experimental.capture-marker-attribute`	Boolean	`false`	Capture Log4j markers as attributes.
`otel.instrumentation.log4j-appender.experimental.capture-mdc-attributes`	String	NA	Comma-separated list of context data attributes to capture. Use `*` to capture all attributes.

Example: Collecting Logs with OTEL Java Agent

Clone the Spring PetClinic Repository:

git clone https://github.com/SigNoz/spring-petclinic

Build the application:
```
./mvnw package
```
Run the application:

OTEL_LOGS_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.{region}.signoz.cloud:443" \
OTEL_EXPORTER_OTLP_HEADERS=signoz-ingestion-key=<SIGNOZ_INGESTION_KEY> \
OTEL_RESOURCE_ATTRIBUTES=service.name=myapp \
java -javaagent:/path/opentelemetry-javaagent.jar -jar target/*.jar

To enable settings like experimental log attributes, pass additional arguments:

OTEL_LOGS_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.{region}.signoz.cloud:443" \
OTEL_EXPORTER_OTLP_HEADERS=signoz-ingestion-key=<SIGNOZ_INGESTION_KEY> \
OTEL_RESOURCE_ATTRIBUTES=service.name=myapp \
java -javaagent:/path/opentelemetry-javaagent.jar \
-Dotel.instrumentation.logback-appender.experimental-log-attributes=true \
-jar target/*.jar

OTEL_LOGS_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT="http://<host>:4317" \
OTEL_RESOURCE_ATTRIBUTES=service.name=myapp \
java -javaagent:/path/opentelemetry-javaagent.jar -jar target/*.jar