distribution/context/util.go
Stephen J Day 4b14eef595 Context package to support context-aware logging
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>
2015-02-06 16:20:38 -08:00

35 lines
834 B
Go

package context
import (
"time"
"golang.org/x/net/context"
)
// Since looks up key, which should be a time.Time, and returns the duration
// since that time. If the key is not found, the value returned will be zero.
// This is helpful when inferring metrics related to context execution times.
func Since(ctx context.Context, key interface{}) time.Duration {
startedAtI := ctx.Value(key)
if startedAtI != nil {
if startedAt, ok := startedAtI.(time.Time); ok {
return time.Since(startedAt)
}
}
return 0
}
// GetStringValue returns a string value from the context. The empty string
// will be returned if not found.
func GetStringValue(ctx context.Context, key string) (value string) {
stringi := ctx.Value(key)
if stringi != nil {
if valuev, ok := stringi.(string); ok {
value = valuev
}
}
return value
}