enable configuring several log outputs

setup.go

@@ -29,6 +29,7 @@ const (
 	envLoggingFmt = "GOLOG_LOG_FMT"
 
 	envLoggingFile = "GOLOG_FILE" // /path/to/file
+	envLoggingOutput = "GOLOG_OUTPUT" // possible values: stdout|stderr|file combine multiple values with '+'
 )
 
 type LogFormat int
@@ -263,5 +264,50 @@ func configFromEnv() Config {
 		cfg.Stderr = false
 	}
 
+	output := os.Getenv(envLoggingOutput)
+	//TODO: fix lanzafame's super lazy impl...
+	switch output {
+	case "stdout":
+		cfg.Stdout = true
+		cfg.Stderr = false
+		cfg.File = ""
+	case "stderr":
+		cfg.Stderr = true
+		cfg.Stdout = false
+		cfg.File = ""
+	case "file":
+		cfg.File = os.Getenv(envLoggingFile)
+		if cfg.File != "" {
+			fmt.Fprint(os.Stderr, "please specify a GOLOG_FILE value to write to")
+		}
+		cfg.Stderr = false
+		cfg.Stdout = false
+	case "stdout+file", "file+stdout":
+		cfg.File = os.Getenv(envLoggingFile)
+		if cfg.File != "" {
+			fmt.Fprint(os.Stderr, "please specify a GOLOG_FILE value to write to")
+		}
+		cfg.Stderr = false
+		cfg.Stdout = true
+	case "stderr+file", "file+stderr":
+		cfg.File = os.Getenv(envLoggingFile)
+		if cfg.File != "" {
+			fmt.Fprint(os.Stderr, "please specify a GOLOG_FILE value to write to")
+		}
+		cfg.Stderr = true
+		cfg.Stdout = false
+	case "stdout+stderr", "stderr+stdout":
+		cfg.File = ""
+		cfg.Stderr = true
+		cfg.Stdout = true
+	case "stdout+stderr+file", "stdout+file+stderr", "stderr+stdout+file", "stderr+file+stdout", "file+stdout+stderr", "file+stderr+stdout":
+		cfg.File = os.Getenv(envLoggingFile)
+		if cfg.File != "" {
+			fmt.Fprint(os.Stderr, "please specify a GOLOG_FILE value to write to")
+		}
+		cfg.Stderr = true
+		cfg.Stdout = true
+	}
+
 	return cfg
 }

setup_test.go

@@ -3,6 +3,7 @@ package log
 import (
 	"bytes"
 	"io"
+	"io/ioutil"
 	"os"
 	"strings"
 	"testing"
@@ -37,3 +38,87 @@ func TestGetLoggerDefault(t *testing.T) {
 	}
 
 }
+
+func TestLogToFileAndStderr(t *testing.T) {
+	// setup stderr
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("failed to open pipe: %v", err)
+	}
+
+	stderr := os.Stderr
+	os.Stderr = w
+	defer func() {
+		os.Stderr = stderr
+	}()
+
+	// setup file
+	logfile, err := ioutil.TempFile("", "go-log-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(logfile.Name())
+
+	os.Setenv(envLoggingFile, logfile.Name())
+
+	// set log output env var
+	os.Setenv(envLoggingOutput, "file+stderr")
+
+	SetupLogging(configFromEnv())
+
+	log := getLogger("test")
+
+	want := "scooby"
+	log.Error(want)
+	w.Close()
+
+	buf := &bytes.Buffer{}
+	if _, err := io.Copy(buf, r); err != nil && err != io.ErrClosedPipe {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if !strings.Contains(buf.String(), want) {
+		t.Errorf("got %q, wanted it to contain log output", buf.String())
+	}
+
+	content, err := ioutil.ReadFile(logfile.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.Contains(string(content), want) {
+		t.Logf("want: '%s', got: '%s'", want, string(content))
+		t.Fail()
+	}
+}
+
+func TestLogToFile(t *testing.T) {
+	// get tmp log file
+	logfile, err := ioutil.TempFile("", "go-log-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(logfile.Name())
+
+	// set the go-log file env var
+	os.Setenv(envLoggingFile, logfile.Name())
+
+	SetupLogging(configFromEnv())
+
+	log := getLogger("test")
+
+	// write log to file
+	want := "grokgrokgrok"
+	log.Error(want)
+
+	// read log file and check contents
+	content, err := ioutil.ReadFile(logfile.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.Contains(string(content), want) {
+		t.Logf("want: '%s', got: '%s'", want, string(content))
+		t.Fail()
+	}
+}
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