logging

README

Per Request Logger Settings

The functions here support request scoped log settings. Specifically, the log level and a custom log field can be set with the ctxlogrus context logger based on http Header values with the grpc-gateway or via grpc metadata.

The metadata annotator accepts input headers -H "log-trace-key: <value>" and -H "log-level: <level>", but with or without it the input headers -H "grpc-gateway-log-trace-key: <value>" and -H "grpc-gateway-log-level: <level>" will also work.

The log-trace-key value is intended to be used for simplifying the process of isolating logs for a single request (so that the request-id doesn't have to be overridden or determined) or a class or requests.

The LogLevelInterceptor needs to be placed after the ctxlogrus.UnaryServerInterceptor, and accepts its own default logging level, so that the ctxlogrus interceptor (and the interceptors between it and this one) can be allowed to log at a different level than the proceeding ones even without setting it in the request (for example, to always/never log the Info message in the ctxlogrus interceptor, despite having a higher/lower log level). Note that the LogLevelInterceptor cannot effect whether or not the Info level message in the ctxlogrus.UnaryServerInterceptor is printed or not.

The helper function CopyLoggerWithLevel can be used to make a deep copy of a logger at a new level, or using CopyLoggerWithLevel(entry.Logger, level).WithFields(entry.Data) can copy a logrus.Entry.

Documentation

Index

• func Annotator(ctx context.Context, req *http.Request) metadata.MD
• func CopyLoggerWithLevel(logger *logrus.Logger, lvl logrus.Level) *logrus.Logger
• func LogLevelInterceptor(defaultLevel logrus.Level) grpc.UnaryServerInterceptor

Functions

func Annotator

func Annotator(ctx context.Context, req *http.Request) metadata.MD

Annotator is a function that reads the http headers of incoming requests searching for special logging arguments

func CopyLoggerWithLevel

func CopyLoggerWithLevel(logger *logrus.Logger, lvl logrus.Level) *logrus.Logger

CopyLoggerWithLevel makes a copy of the given (logrus) logger at the logger level. If copying an entry, use CopyLoggerWithLevel(entry.Logger, level).WithFields(entry.Data) on the result (changes to these entries' fields will not affect each other).

func LogLevelInterceptor

func LogLevelInterceptor(defaultLevel logrus.Level) grpc.UnaryServerInterceptor

LogLevelInterceptor sets the level of the logger in the context to either the default or the value set in the context via grpc metadata. Also sets the custom log tag if present for pseudo-tracing purposes