// Copyright 2017 Michal Witkowski. All Rights Reserved.
// See LICENSE for licensing terms.

//
/*
grpc_logging is a "parent" package for gRPC logging middlewares.

General functionality of all middleware

The gRPC logging middleware populates request-scoped data to `grpc_ctxtags.Tags` that relate to the current gRPC call
(e.g. service and method names).

Once the gRPC logging middleware has added the gRPC specific Tags to the ctx they will then be written with the logs
that are made using the `ctx_logrus` or `ctx_zap` loggers.

All logging middleware will emit a final log statement. It is based on the error returned by the handler function,
the gRPC status code, an error (if any) and it will emit at a level controlled via `WithLevels`.

This parent package

This particular package is intended for use by other middleware, logging or otherwise. It contains interfaces that other
logging middlewares *could* share . This allows code to be shared between different implementations.

Field names

All field names of loggers follow the OpenTracing semantics definitions, with `grpc.` prefix if needed:
https://github.com/opentracing/specification/blob/master/semantic_conventions.md

Implementations

There are three implementations at the moment: logrus, zap and kit

See relevant packages below.
*/
package grpc_logging