Tracing, Log Correlation

In this section we explain how you can hook your own trace implementation into the trace subsystem.

If you need, you can write your own implementation for tracing / log correlation.
As a good point to start you may take a look at class ...logging.simpleTrace.SimpleTraceContext.

Define the context and its factory

Your trace implementation implements interface ...logging.TraceContext. OAG needs a fresh instance for every request, so the context is a plain class and a ...logging.TraceContextFactory component creates it. The factory's type() is the value configured in the master configuration file.
Example:

public class MyTraceContext implements TraceContext {/*...*/}

@Component
public class MyTraceContextFactory implements TraceContextFactory {

    @Override
    public String type() {
        return "myTraceContext";
    }

    @Override
    public TraceContext create() {
        return new MyTraceContext();
    }
}

If the context needs the configuration, inject MainConfig into the factory and pass it to the context's constructor (see ...logging.simpleTrace.SimpleTraceContextFactory).

Implement methods

Study the Javadoc of ...logging.TraceContext to understand under what conditions the methods are invoked by OAG. Implement them accordingly.
If you do not support some of the common configuration settings in the traceProfile:

• Return the value matching the intention of your implementation. E.g. if your implementation does not support upstream trace id communication, make sure you hardcode return false; in the sendTraceResponse method implementation.
• Document this in Javadoc of your class (recommended)

Configure your custom implementation to be used by OAG

The value returned by your factory's type() must be configured in the master configuration file, section traceProfile, attribute type in order to be used by OAG.
For the example provided above, the required configuration is:

traceProfile:
  type: myTraceContext
  # ...

Test your implementation

Write tests to verify functionality of your trace implementation. Start OAG and verify your trace id is found in the log and sent to downstream and upstream systems as required.