Correlation ID

• A CorrelationID is a Unique identifier assigned to a request that allows tracking it through various components.
• We can print CorrelationID along with Our logs.
• It is easier to debug across micro services using correlation ID.
• Helps to the request in a distributed system.
• Each client will have a unique CorrelationID Corresponding to its request.
• Since 3.2.1 spring boot adds this ID using simple configuration as follows
• Add the dependency of “micrometer – tracing – bridge – brave” or “ Spring boot actuator”
• Add property management.tracing.enabled=true.
• Example
• Old way using once per request Filter
• https://github.com/gauravmatta/springmvc/tree/master/complaint-manager/src/main/java/com/springimplant/complaintmanager
• Recent way using using configuration
• https://github.com/gauravmatta/springmvc/tree/master/springredis
• Correlated logs in Spring Apps With reactive parts
• We use MDC I.e. Mapped Diagnostics Context.
• MDC is map Backed by thread, local storage.
• We add correlation ID in MDC and response header So that we can correlate logs corresponding to request/Response
• We can use a correlation Filter() as a bean in oncePerRequestFilter()
• Add a logging pattern with correlation key in properties.
• Context. Write() and context.store helps To store data in context reactor.
• To access data back we use tap() or handle().
• Example : https://github.com/gauravmatta/springmvc/tree/master/springredis