forked from TrueCloudLab/distribution
4b14eef595
The new context package supports context-aware logging, integrating with logrus. Several utilities are provided to associate http requests with a context, ensuring that one can trace log messages all the way through a context-aware call stack. A full description of this functionality is available in doc.go. Signed-off-by: Stephen J Day <stephen.day@docker.com>
88 lines
2.4 KiB
Go
88 lines
2.4 KiB
Go
package context
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import (
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"fmt"
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"github.com/Sirupsen/logrus"
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"golang.org/x/net/context"
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)
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// Logger provides a leveled-logging interface.
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type Logger interface {
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// standard logger methods
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Print(args ...interface{})
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Printf(format string, args ...interface{})
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Println(args ...interface{})
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Fatal(args ...interface{})
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Fatalf(format string, args ...interface{})
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Fatalln(args ...interface{})
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Panic(args ...interface{})
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Panicf(format string, args ...interface{})
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Panicln(args ...interface{})
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// Leveled methods, from logrus
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Debug(args ...interface{})
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Debugf(format string, args ...interface{})
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Debugln(args ...interface{})
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Error(args ...interface{})
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Errorf(format string, args ...interface{})
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Errorln(args ...interface{})
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Info(args ...interface{})
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Infof(format string, args ...interface{})
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Infoln(args ...interface{})
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Warn(args ...interface{})
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Warnf(format string, args ...interface{})
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Warnln(args ...interface{})
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}
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// WithLogger creates a new context with provided logger.
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func WithLogger(ctx context.Context, logger Logger) context.Context {
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return context.WithValue(ctx, "logger", logger)
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}
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// GetLogger returns the logger from the current context, if present. If one
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// or more keys are provided, they will be resolved on the context and
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// included in the logger. While context.Value takes an interface, any key
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// argument passed to GetLogger will be passed to fmt.Sprint when expanded as
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// a logging key field. If context keys are integer constants, for example,
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// its recommended that a String method is implemented.
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func GetLogger(ctx context.Context, keys ...interface{}) Logger {
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return getLogrusLogger(ctx, keys...)
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}
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// GetLogrusLogger returns the logrus logger for the context. If one more keys
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// are provided, they will be resolved on the context and included in the
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// logger. Only use this function if specific logrus functionality is
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// required.
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func getLogrusLogger(ctx context.Context, keys ...interface{}) *logrus.Entry {
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var logger *logrus.Entry
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// Get a logger, if it is present.
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loggerInterface := ctx.Value("logger")
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if loggerInterface != nil {
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if lgr, ok := loggerInterface.(*logrus.Entry); ok {
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logger = lgr
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}
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}
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if logger == nil {
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// If no logger is found, just return the standard logger.
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logger = logrus.NewEntry(logrus.StandardLogger())
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}
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fields := logrus.Fields{}
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for _, key := range keys {
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v := ctx.Value(key)
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if v != nil {
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fields[fmt.Sprint(key)] = v
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}
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}
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return logger.WithFields(fields)
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}
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