consul/sdk/testutil/testlog.go

package testutil

import (
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"strings"
	"testing"

	"github.com/hashicorp/go-hclog"
)

var sendTestLogsToStdout bool

func init() {
	sendTestLogsToStdout = os.Getenv("NOLOGBUFFER") == "1"
}

// Deprecated: use Logger(t)
func TestLogger(t testing.TB) *log.Logger {
	return log.New(&testWriter{t}, t.Name()+": ", log.LstdFlags)
}

func NewDiscardLogger() hclog.Logger {
	return hclog.New(&hclog.LoggerOptions{
		Level:  0,
		Output: ioutil.Discard,
	})
}

func Logger(t testing.TB) hclog.InterceptLogger {
	return LoggerWithOutput(t, &testWriter{t})
}

func LoggerWithOutput(t testing.TB, output io.Writer) hclog.InterceptLogger {
	return hclog.NewInterceptLogger(&hclog.LoggerOptions{
		Name:   t.Name(),
		Level:  hclog.Debug,
		Output: output,
	})
}

// Deprecated: use LoggerWithName(t)
func TestLoggerWithName(t testing.TB, name string) *log.Logger {
	return log.New(&testWriter{t}, "test["+name+"]: ", log.LstdFlags)
}

func LoggerWithName(t testing.TB, name string) hclog.InterceptLogger {
	return hclog.NewInterceptLogger(&hclog.LoggerOptions{
		Name:   "test[" + name + "]",
		Level:  hclog.Debug,
		Output: &testWriter{t},
	})
}

func TestWriter(t testing.TB) io.Writer {
	return &testWriter{t}
}

type testWriter struct {
	t testing.TB
}

func (tw *testWriter) Write(p []byte) (n int, err error) {
	if tw.t != nil {
		tw.t.Helper()
	}
	if sendTestLogsToStdout || tw.t == nil {
		fmt.Fprint(os.Stdout, strings.TrimSpace(string(p))+"\n")
	} else {
		defer func() {
			if r := recover(); r != nil {
				if sr, ok := r.(string); ok {
					if strings.HasPrefix(sr, "Log in goroutine after ") {
						// These sorts of panics are undesirable, but requires
						// total control over goroutine lifetimes to correct.
						fmt.Fprint(os.Stdout, "SUPPRESSED PANIC: "+sr+"\n")
						return
					}
				}
				panic(r)
			}
		}()
		tw.t.Log(strings.TrimSpace(string(p)))
	}
	return len(p), nil
}