diff --git a/README.md b/README.md index b7c8caa9..cc5dab7e 100644 --- a/README.md +++ b/README.md @@ -40,7 +40,7 @@ plain text): ![Colored](http://i.imgur.com/PY7qMwd.png) -With `log.SetFormatter(&log.JSONFormatter{})`, for easy parsing by logstash +With `logrus.SetFormatter(&logrus.JSONFormatter{})`, for easy parsing by logstash or Splunk: ```text @@ -60,7 +60,7 @@ ocean","size":10,"time":"2014-03-10 19:57:38.562264131 -0400 EDT"} "time":"2014-03-10 19:57:38.562543128 -0400 EDT"} ``` -With the default `log.SetFormatter(&log.TextFormatter{})` when a TTY is not +With the default `logrus.SetFormatter(&logrus.TextFormatter{})` when a TTY is not attached, the output is compatible with the [logfmt](https://pkg.go.dev/github.com/kr/logfmt) format: @@ -75,17 +75,18 @@ time="2015-03-26T01:27:38-04:00" level=fatal msg="The ice breaks!" err=&{0x20822 To ensure this behaviour even if a TTY is attached, set your formatter as follows: ```go - log.SetFormatter(&log.TextFormatter{ - DisableColors: true, - FullTimestamp: true, - }) +logrus.SetFormatter(&logrus.TextFormatter{ + DisableColors: true, + FullTimestamp: true, +}) ``` #### Logging Method Name If you wish to add the calling method as a field, instruct the logger via: + ```go -log.SetReportCaller(true) +logrus.SetReportCaller(true) ``` This adds the caller as 'method' like so: @@ -100,11 +101,11 @@ time="2015-03-26T01:27:38-04:00" level=fatal method=github.com/sirupsen/arcticcr Note that this does add measurable overhead - the cost will depend on the version of Go, but is between 20 and 40% in recent tests with 1.6 and 1.7. You can validate this in your environment via benchmarks: -``` + +```bash go test -bench=.*CallerTracing ``` - #### Case-sensitivity The organization's name was changed to lower-case--and this will not be changed @@ -118,12 +119,10 @@ The simplest way to use Logrus is simply the package-level exported logger: ```go package main -import ( - log "github.com/sirupsen/logrus" -) +import "github.com/sirupsen/logrus" func main() { - log.WithFields(log.Fields{ + logrus.WithFields(logrus.Fields{ "animal": "walrus", }).Info("A walrus appears") } @@ -139,6 +138,7 @@ package main import ( "os" + log "github.com/sirupsen/logrus" ) @@ -190,26 +190,27 @@ package main import ( "os" + "github.com/sirupsen/logrus" ) // Create a new instance of the logger. You can have any number of instances. -var log = logrus.New() +var logger = logrus.New() func main() { // The API for setting attributes is a little different than the package level - // exported logger. See Godoc. - log.Out = os.Stdout + // exported logger. See Godoc. + logger.Out = os.Stdout // You could set this to any `io.Writer` such as a file // file, err := os.OpenFile("logrus.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666) // if err == nil { - // log.Out = file + // logger.Out = file // } else { - // log.Info("Failed to log to file, using default stderr") + // logger.Info("Failed to log to file, using default stderr") // } - log.WithFields(logrus.Fields{ + logger.WithFields(logrus.Fields{ "animal": "walrus", "size": 10, }).Info("A group of walrus emerges from the ocean") @@ -219,12 +220,12 @@ func main() { #### Fields Logrus encourages careful, structured logging through logging fields instead of -long, unparseable error messages. For example, instead of: `log.Fatalf("Failed +long, unparseable error messages. For example, instead of: `logrus.Fatalf("Failed to send event %s to topic %s with key %d")`, you should log the much more discoverable: ```go -log.WithFields(log.Fields{ +logrus.WithFields(logrus.Fields{ "event": event, "topic": topic, "key": key, @@ -245,12 +246,12 @@ seen as a hint you should add a field, however, you can still use the Often it's helpful to have fields _always_ attached to log statements in an application or parts of one. For example, you may want to always log the `request_id` and `user_ip` in the context of a request. Instead of writing -`log.WithFields(log.Fields{"request_id": request_id, "user_ip": user_ip})` on +`logger.WithFields(logrus.Fields{"request_id": request_id, "user_ip": user_ip})` on every line, you can create a `logrus.Entry` to pass around instead: ```go -requestLogger := log.WithFields(log.Fields{"request_id": request_id, "user_ip": user_ip}) -requestLogger.Info("something happened on that request") # will log request_id and user_ip +requestLogger := logger.WithFields(logrus.Fields{"request_id": request_id, "user_ip": user_ip}) +requestLogger.Info("something happened on that request") // will log request_id and user_ip requestLogger.Warn("something not great happened") ``` @@ -264,24 +265,27 @@ Logrus comes with [built-in hooks](hooks/). Add those, or your custom hook, in `init`: ```go +package main + import ( - log "github.com/sirupsen/logrus" - "gopkg.in/gemnasium/logrus-airbrake-hook.v2" // the package is named "airbrake" - logrus_syslog "github.com/sirupsen/logrus/hooks/syslog" "log/syslog" + + "github.com/sirupsen/logrus" + airbrake "gopkg.in/gemnasium/logrus-airbrake-hook.v2" + logrus_syslog "github.com/sirupsen/logrus/hooks/syslog" ) func init() { // Use the Airbrake hook to report errors that have Error severity or above to // an exception tracker. You can create custom hooks, see the Hooks section. - log.AddHook(airbrake.NewHook(123, "xyz", "production")) + logrus.AddHook(airbrake.NewHook(123, "xyz", "production")) hook, err := logrus_syslog.NewSyslogHook("udp", "localhost:514", syslog.LOG_INFO, "") if err != nil { - log.Error("Unable to connect to local syslog daemon") + logrus.Error("Unable to connect to local syslog daemon") } else { - log.AddHook(hook) + logrus.AddHook(hook) } } ``` @@ -295,15 +299,15 @@ A list of currently known service hooks can be found in this wiki [page](https:/ Logrus has seven logging levels: Trace, Debug, Info, Warning, Error, Fatal and Panic. ```go -log.Trace("Something very low level.") -log.Debug("Useful debugging information.") -log.Info("Something noteworthy happened!") -log.Warn("You should probably take a look at this.") -log.Error("Something failed but I'm not quitting.") +logrus.Trace("Something very low level.") +logrus.Debug("Useful debugging information.") +logrus.Info("Something noteworthy happened!") +logrus.Warn("You should probably take a look at this.") +logrus.Error("Something failed but I'm not quitting.") // Calls os.Exit(1) after logging -log.Fatal("Bye.") +logrus.Fatal("Bye.") // Calls panic() after logging -log.Panic("I'm bailing.") +logrus.Panic("I'm bailing.") ``` You can set the logging level on a `Logger`, then it will only log entries with @@ -311,13 +315,13 @@ that severity or anything above it: ```go // Will log anything that is info or above (warn, error, fatal, panic). Default. -log.SetLevel(log.InfoLevel) +logrus.SetLevel(logrus.InfoLevel) ``` -It may be useful to set `log.Level = logrus.DebugLevel` in a debug or verbose +It may be useful to set `logrus.Level = logrus.DebugLevel` in a debug or verbose environment if your application has that. -Note: If you want different log levels for global (`log.SetLevel(...)`) and syslog logging, please check the [syslog hook README](hooks/syslog/README.md#different-log-levels-for-local-and-remote-logging). +Note: If you want different log levels for global (`logrus.SetLevel(...)`) and syslog logging, please check the [syslog hook README](hooks/syslog/README.md#different-log-levels-for-local-and-remote-logging). #### Entries @@ -340,17 +344,17 @@ could do: ```go import ( - log "github.com/sirupsen/logrus" + "github.com/sirupsen/logrus" ) func init() { // do something here to set environment depending on an environment variable // or command-line flag if Environment == "production" { - log.SetFormatter(&log.JSONFormatter{}) + logrus.SetFormatter(&logrus.JSONFormatter{}) } else { // The TextFormatter is default, you don't actually have to do this. - log.SetFormatter(&log.TextFormatter{}) + logrus.SetFormatter(&logrus.TextFormatter{}) } } ``` @@ -393,10 +397,9 @@ requiring a `Format` method. `Format` takes an `*Entry`. `entry.Data` is a default ones (see Entries section above): ```go -type MyJSONFormatter struct { -} +type MyJSONFormatter struct{} -log.SetFormatter(new(MyJSONFormatter)) +logrus.SetFormatter(new(MyJSONFormatter)) func (f *MyJSONFormatter) Format(entry *Entry) ([]byte, error) { // Note this doesn't include Time, Level and Message which are available on @@ -462,10 +465,11 @@ Logrus has a built-in facility for asserting the presence of log messages. This ```go import( + "testing" + "github.com/sirupsen/logrus" "github.com/sirupsen/logrus/hooks/test" "github.com/stretchr/testify/assert" - "testing" ) func TestSomething(t*testing.T){ @@ -488,13 +492,13 @@ level message is logged. The registered handlers will be executed before logrus performs an `os.Exit(1)`. This behavior may be helpful if callers need to gracefully shut down. Unlike a `panic("Something went wrong...")` call which can be intercepted with a deferred `recover` a call to `os.Exit(1)` can not be intercepted. -``` -... +```go +// ... handler := func() { // gracefully shut down something... } logrus.RegisterExitHandler(handler) -... +// ... ``` #### Thread safety