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Logging

LangChain4j uses SLF4J for logging, allowing you to plug in any logging backend you prefer, such as Logback or Log4j.

Pure Java​

You can enable logging of each request and response to the LLM by setting .logRequests(true) and .logResponses(true) when creating an instance of the model:

OpenAiChatModel.builder()
    ...
    .logRequests(true)
    .logResponses(true)
    .build();

Make sure you have one of the SLF4J logging backends in your dependencies, for example, Logback:

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.5.8</version>
</dependency>

Quarkus​

When using Quarkus integration, logging is configured in the application.properties file:

...
quarkus.langchain4j.openai.chat-model.log-requests = true
quarkus.langchain4j.openai.chat-model.log-responses = true
quarkus.log.console.enable = true
quarkus.log.file.enable = false

These properties can also be set and changed in the Quarkus Dev UI, when running the application in dev mode (mvn quarkus:dev). The Dev UI is then available at http://localhost:8080/q/dev-ui.

Spring Boot​

When using Spring Boot integration, logging is configured in the application.properties file:

...
langchain4j.open-ai.chat-model.log-requests = true
langchain4j.open-ai.chat-model.log-responses = true
logging.level.dev.langchain4j = DEBUG