Documentation
¶
Overview ¶
Package jsonlog provides a Logger that logs structured JSON to Stderr by default. When used on the various Cloud Compute environments (Cloud Run, Cloud Functions, GKE, etc.) these JSON messages will be parsed by the Cloud Logging agent and transformed into a message format that mirrors that of the Cloud Logging API.
Index ¶
- type Logger
- func (l *Logger) Alertf(format string, a ...interface{})
- func (l *Logger) Criticalf(format string, a ...interface{})
- func (l *Logger) Debugf(format string, a ...interface{})
- func (l *Logger) Emergencyf(format string, a ...interface{})
- func (l *Logger) Errorf(format string, a ...interface{})
- func (l *Logger) Infof(format string, a ...interface{})
- func (l *Logger) Log(e logging.Entry)
- func (l *Logger) Noticef(format string, a ...interface{})
- func (l *Logger) Warnf(format string, a ...interface{})
- func (l *Logger) WithLabels(labels map[string]string) *Logger
- func (l *Logger) WithRequest(r *http.Request) *Logger
- type LoggerOption
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Logger ¶
type Logger struct {
// contains filtered or unexported fields
}
Logger is used for logging JSON entries.
func NewLogger ¶
func NewLogger(parent string, opts ...LoggerOption) (*Logger, error)
NewLogger creates a Logger that logs structured JSON to Stderr. The value of parent must be in the format of:
projects/PROJECT_ID folders/FOLDER_ID billingAccounts/ACCOUNT_ID organizations/ORG_ID
Example ¶
package main
import (
"cloud.google.com/go/logging/jsonlog"
)
func main() {
l, err := jsonlog.NewLogger("projects/PROJECT_ID")
if err != nil {
// TODO: handle error.
}
l.Infof("Hello World!")
}
Output:
func (*Logger) Alertf ¶
Alertf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Criticalf ¶
Criticalf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Debugf ¶
Debugf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Emergencyf ¶
Emergencyf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Errorf ¶
Errorf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Infof ¶
Infof is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Log ¶
Log an Entry. Note that not all of the fields in entry will used when writting the log message, only those that are mentioned https://cloud.google.com/logging/docs/structured-logging will be logged.
func (*Logger) Noticef ¶
Noticef is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) Warnf ¶
Warnf is a convenience method for writing an Entry with a Debug Severity and the provided formatted message.
func (*Logger) WithLabels ¶
WithLabels creates a new JSONLogger based off an existing one. The labels provided will be added to the loggers existing labels, replacing any overlapping keys with the new values.
Example ¶
package main
import (
"cloud.google.com/go/logging/jsonlog"
)
func main() {
l, err := jsonlog.NewLogger("projects/PROJECT_ID")
if err != nil {
// TODO: handle error.
}
l.Infof("Hello World!")
// Create a logger that always provides additional context by adding labels
// to all logged messages.
l2 := l.WithLabels(map[string]string{"foo": "bar"})
l2.Infof("Hello World, with more context!")
}
Output:
func (*Logger) WithRequest ¶
WithRequest creates a new JSONLogger based off an existing one with request information populated. By giving a Logger a request context all logs will be auto-populated with some basic information about the request as well as tracing details, if included.
type LoggerOption ¶
type LoggerOption interface {
// contains filtered or unexported methods
}
LoggerOption is a configuration option for a Logger.
func CommonLabels ¶
func CommonLabels(m map[string]string) LoggerOption
CommonLabels are labels that apply to all log entries written from a Logger, so that you don't have to repeat them in each log entry's Labels field. If any of the log entries contains a (key, value) with the same key that is in CommonLabels, then the entry's (key, value) overrides the one in CommonLabels.
func OnErrorHook ¶
func OnErrorHook(hook func(error)) LoggerOption
OnErrorHook registers a function that will be called anytime an error occurs during logging.
func WithWriter ¶
func WithWriter(w io.Writer) LoggerOption
WithWriter changes where the JSON payloads of a Logger are written to. By default they are written to Stderr.
Example (Multiwriter) ¶
package main
import (
"io"
"os"
"cloud.google.com/go/logging/jsonlog"
)
func main() {
// Create a new writer that also logs messages to a second location
w := io.MultiWriter(os.Stderr, os.Stdout)
l, err := jsonlog.NewLogger("projects/PROJECT_ID", jsonlog.WithWriter(w))
if err != nil {
// TODO: handle error.
}
l.Infof("Hello World!")
}
Output: {"message":"Hello World!","severity":"INFO"}
Source Files