Logids

Logids are unique identifiers assigned to log entries or to a set of related logs to enable correlation and traceability across systems. They serve as persistent references that help connect events occurring in different components, services, or time periods, facilitating search, filtering, and the reconstruction of workflows.

In practice, a logid is often generated per request or operation and propagated across service boundaries. It is typically carried through log lines, event messages, and context metadata so that related events can be linked even when they are produced by separate processes or machines. The logid can be a standalone identifier or part of a broader tracing scheme that includes additional identifiers for sub-operations.

Common formats for logids include UUIDs (RFC 4122), Snowflake-style numeric IDs, or custom strings that may incorporate timestamps, host identifiers, and sequence numbers. In distributed tracing, logids align with concepts such as trace-id and span-id, where a trace-id identifies an end-to-end request and span-ids identify constituent operations; logs may include both a logid and a trace-id to enable cross-service correlation.

Generation and propagation are critical considerations. A logid may be created at the network boundary (for example, by an API gateway) or within the first service handling a request and should be propagated through all downstream calls and logging systems. Structured logging practices encourage explicitly recording the logid in each log event to improve searchability and interoperability with log-management tools.

Security and privacy considerations include avoiding the exposure of sensitive internal topology through logids, and ensuring that log entries themselves do not disclose confidential data merely by their identifiers. See also: distributed tracing, correlation ID, logging, structured logging, UUID.