zlog/log/log_example_test.go

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// +build !binary_log
package log_test
import (
"errors"
"flag"
"os"
"time"
"github.com/rs/zerolog"
"github.com/rs/zerolog/log"
)
// setup would normally be an init() function, however, there seems
// to be something awry with the testing framework when we set the
// global Logger from an init()
func setup() {
// UNIX Time is faster and smaller than most timestamps
// If you set zerolog.TimeFieldFormat to an empty string,
// logs will write with UNIX time
zerolog.TimeFieldFormat = ""
// In order to always output a static time to stdout for these
// examples to pass, we need to override zerolog.TimestampFunc
// and log.Logger globals -- you would not normally need to do this
zerolog.TimestampFunc = func() time.Time {
return time.Date(2008, 1, 8, 17, 5, 05, 0, time.UTC)
}
log.Logger = zerolog.New(os.Stdout).With().Timestamp().Logger()
}
// Simple logging example using the Print function in the log package
// Note that both Print and Printf are at the debug log level by default
func ExamplePrint() {
setup()
log.Print("hello world")
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// Output: {"level":"debug","time":1199811905,"message":"hello world"}
}
// Simple logging example using the Printf function in the log package
func ExamplePrintf() {
setup()
log.Printf("hello %s", "world")
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// Output: {"level":"debug","time":1199811905,"message":"hello world"}
}
// Example of a log with no particular "level"
func ExampleLog() {
setup()
log.Log().Msg("hello world")
// Output: {"time":1199811905,"message":"hello world"}
}
// Example of a conditional level based on the presence of an error.
func ExampleErr() {
setup()
err := errors.New("some error")
log.Err(err).Msg("hello world")
log.Err(nil).Msg("hello world")
// Output: {"level":"error","error":"some error","time":1199811905,"message":"hello world"}
// {"level":"info","time":1199811905,"message":"hello world"}
}
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// Example of a log at a particular "level" (in this case, "trace")
func ExampleTrace() {
setup()
log.Trace().Msg("hello world")
// Output: {"level":"trace","time":1199811905,"message":"hello world"}
}
// Example of a log at a particular "level" (in this case, "debug")
func ExampleDebug() {
setup()
log.Debug().Msg("hello world")
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// Output: {"level":"debug","time":1199811905,"message":"hello world"}
}
// Example of a log at a particular "level" (in this case, "info")
func ExampleInfo() {
setup()
log.Info().Msg("hello world")
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// Output: {"level":"info","time":1199811905,"message":"hello world"}
}
// Example of a log at a particular "level" (in this case, "warn")
func ExampleWarn() {
setup()
log.Warn().Msg("hello world")
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// Output: {"level":"warn","time":1199811905,"message":"hello world"}
}
// Example of a log at a particular "level" (in this case, "error")
func ExampleError() {
setup()
log.Error().Msg("hello world")
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// Output: {"level":"error","time":1199811905,"message":"hello world"}
}
// Example of a log at a particular "level" (in this case, "fatal")
func ExampleFatal() {
setup()
err := errors.New("A repo man spends his life getting into tense situations")
service := "myservice"
log.Fatal().
Err(err).
Str("service", service).
Msgf("Cannot start %s", service)
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// Outputs: {"level":"fatal","time":1199811905,"error":"A repo man spends his life getting into tense situations","service":"myservice","message":"Cannot start myservice"}
}
// TODO: Panic
// This example uses command-line flags to demonstrate various outputs
// depending on the chosen log level.
func Example() {
setup()
debug := flag.Bool("debug", false, "sets log level to debug")
flag.Parse()
// Default level for this example is info, unless debug flag is present
zerolog.SetGlobalLevel(zerolog.InfoLevel)
if *debug {
zerolog.SetGlobalLevel(zerolog.DebugLevel)
}
log.Debug().Msg("This message appears only when log level set to Debug")
log.Info().Msg("This message appears when log level set to Debug or Info")
if e := log.Debug(); e.Enabled() {
// Compute log output only if enabled.
value := "bar"
e.Str("foo", value).Msg("some debug message")
}
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// Output: {"level":"info","time":1199811905,"message":"This message appears when log level set to Debug or Info"}
}
// TODO: Output
// TODO: With
// TODO: Level
// TODO: Sample
// TODO: Hook
// TODO: WithLevel
// TODO: Ctx