Correlation ID

The Correlation ID plugin lets you correlate requests and responses using a unique ID transmitted as HTTP headers.

When you enable this plugin, it adds a new header to all of the requests processed by Kong Gateway. This header contains the name configured in the config.header_name variable, and a unique value is generated according to config.generator.

This header is always added in calls to your upstream services, and optionally echoed back to your clients according to the config.echo_downstream setting.

If a header with the same name is already present in the client request, the plugin honors it and does not tamper with it.

Correlation ID uses a generator (config.generator) to create different headers for requests processed by Kong Gateway.

uuid

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

This format generates a hexadecimal UUID for each request.

uuid#counter

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx#counter

This format generates a single UUID on a per-worker basis, and the requests append a counter to the UUID after a # character. The counter value starts at 0 for each worker, and gets incremented independently of the others.

This format provides better performance, but might be harder to store or process for analyzing (due to its format and low cardinality).

tracker

Format:

ip-port-pid-connection-connection_requests-timestamp

This correlation ID contains more practical implications for each request.

The following is a detailed description of the field: