Feature #1246 - Remote syslog (#1301)

* Remote syslog

* golint

* Initialize mutex

caddyhttp/httpserver/logger.go

@@ -0,0 +1,148 @@
+package httpserver
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"os"
+	"strings"
+	"sync"
+
+	"github.com/hashicorp/go-syslog"
+	"github.com/mholt/caddy"
+)
+
+var remoteSyslogPrefixes = map[string]string{
+	"syslog+tcp://": "tcp",
+	"syslog+udp://": "udp",
+	"syslog://":     "udp",
+}
+
+// Logger is shared between errors and log plugins and supports both logging to
+// a file (with an optional file roller), local and remote syslog servers.
+type Logger struct {
+	Output string
+	*log.Logger
+	Roller *LogRoller
+	writer io.Writer
+	fileMu *sync.RWMutex
+}
+
+// NewTestLogger creates logger suitable for testing purposes
+func NewTestLogger(buffer *bytes.Buffer) *Logger {
+	return &Logger{
+		Logger: log.New(buffer, "", 0),
+		fileMu: new(sync.RWMutex),
+	}
+}
+
+// Println wraps underlying logger with mutex
+func (l Logger) Println(args ...interface{}) {
+	l.fileMu.RLock()
+	l.Logger.Println(args...)
+	l.fileMu.RUnlock()
+}
+
+// Printf wraps underlying logger with mutex
+func (l Logger) Printf(format string, args ...interface{}) {
+	l.fileMu.RLock()
+	l.Logger.Printf(format, args...)
+	l.fileMu.RUnlock()
+}
+
+// Attach binds logger Start and Close functions to
+// controller's OnStartup and OnShutdown hooks.
+func (l *Logger) Attach(controller *caddy.Controller) {
+	if controller != nil {
+		// Opens file or connect to local/remote syslog
+		controller.OnStartup(l.Start)
+
+		// Closes file or disconnects from local/remote syslog
+		controller.OnShutdown(l.Close)
+	}
+}
+
+type syslogAddress struct {
+	network string
+	address string
+}
+
+func parseSyslogAddress(location string) *syslogAddress {
+	for prefix, network := range remoteSyslogPrefixes {
+		if strings.HasPrefix(location, prefix) {
+			return &syslogAddress{
+				network: network,
+				address: strings.TrimPrefix(location, prefix),
+			}
+		}
+	}
+
+	return nil
+}
+
+// Start initializes logger opening files or local/remote syslog connections
+func (l *Logger) Start() error {
+	// initialize mutex on start
+	l.fileMu = new(sync.RWMutex)
+
+	var err error
+
+selectwriter:
+	switch l.Output {
+	case "", "stderr":
+		l.writer = os.Stderr
+
+	case "stdout":
+		l.writer = os.Stdout
+
+	case "syslog":
+		l.writer, err = gsyslog.NewLogger(gsyslog.LOG_ERR, "LOCAL0", "caddy")
+		if err != nil {
+			return err
+		}
+	default:
+
+		if address := parseSyslogAddress(l.Output); address != nil {
+			l.writer, err = gsyslog.DialLogger(address.network, address.address, gsyslog.LOG_ERR, "LOCAL0", "caddy")
+
+			if err != nil {
+				return err
+			}
+
+			break selectwriter
+		}
+
+		var file *os.File
+
+		file, err = os.OpenFile(l.Output, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
+		if err != nil {
+			return err
+		}
+
+		if l.Roller != nil {
+			file.Close()
+			l.Roller.Filename = l.Output
+			l.writer = l.Roller.GetLogWriter()
+		} else {
+			l.writer = file
+		}
+	}
+
+	l.Logger = log.New(l.writer, "", 0)
+
+	return nil
+
+}
+
+// Close closes open log files or connections to syslog.
+func (l *Logger) Close() error {
+	// Will close local/remote syslog connections too :)
+	if closer, ok := l.writer.(io.WriteCloser); ok {
+		l.fileMu.Lock()
+		err := closer.Close()
+		l.fileMu.Unlock()
+		return err
+	}
+
+	return nil
+}

caddyhttp/httpserver/logger_test.go

@@ -0,0 +1,212 @@
+//+build linux darwin
+
+package httpserver
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+
+	"gopkg.in/mcuadros/go-syslog.v2"
+	"gopkg.in/mcuadros/go-syslog.v2/format"
+)
+
+func TestLoggingToStdout(t *testing.T) {
+	testCases := []struct {
+		Output         string
+		ExpectedOutput string
+	}{
+		{
+			Output:         "stdout",
+			ExpectedOutput: "Hello world logged to stdout",
+		},
+	}
+
+	for i, testCase := range testCases {
+		output := captureStdout(func() {
+			logger := Logger{Output: testCase.Output, fileMu: new(sync.RWMutex)}
+
+			if err := logger.Start(); err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+
+			logger.Println(testCase.ExpectedOutput)
+		})
+
+		if !strings.Contains(output, testCase.ExpectedOutput) {
+			t.Fatalf("Test #%d: Expected output to contain: %s, got: %s", i, testCase.ExpectedOutput, output)
+		}
+	}
+}
+
+func TestLoggingToStderr(t *testing.T) {
+
+	testCases := []struct {
+		Output         string
+		ExpectedOutput string
+	}{
+		{
+			Output:         "stderr",
+			ExpectedOutput: "Hello world logged to stderr",
+		},
+		{
+			Output:         "",
+			ExpectedOutput: "Hello world logged to stderr #2",
+		},
+	}
+
+	for i, testCase := range testCases {
+		output := captureStderr(func() {
+			logger := Logger{Output: testCase.Output, fileMu: new(sync.RWMutex)}
+
+			if err := logger.Start(); err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+
+			logger.Println(testCase.ExpectedOutput)
+		})
+
+		if !strings.Contains(output, testCase.ExpectedOutput) {
+			t.Fatalf("Test #%d: Expected output to contain: %s, got: %s", i, testCase.ExpectedOutput, output)
+		}
+	}
+}
+
+func TestLoggingToFile(t *testing.T) {
+	file := filepath.Join(os.TempDir(), "access.log")
+	expectedOutput := "Hello world written to file"
+
+	logger := Logger{Output: file}
+
+	if err := logger.Start(); err != nil {
+		t.Fatalf("Got unexpected error during logger start: %v", err)
+	}
+
+	logger.Print(expectedOutput)
+
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
+		t.Fatalf("Could not read log file content: %v", err)
+	}
+
+	if !bytes.Contains(content, []byte(expectedOutput)) {
+		t.Fatalf("Expected log file to contain: %s, got: %s", expectedOutput, string(content))
+	}
+
+	os.Remove(file)
+}
+
+func TestLoggingToSyslog(t *testing.T) {
+
+	testCases := []struct {
+		Output         string
+		ExpectedOutput string
+	}{
+		{
+			Output:         "syslog://127.0.0.1:5660",
+			ExpectedOutput: "Hello world! Test #1 over tcp",
+		},
+		{
+			Output:         "syslog+tcp://127.0.0.1:5661",
+			ExpectedOutput: "Hello world! Test #2 over tcp",
+		},
+		{
+			Output:         "syslog+udp://127.0.0.1:5662",
+			ExpectedOutput: "Hello world! Test #3 over udp",
+		},
+	}
+
+	for i, testCase := range testCases {
+
+		ch := make(chan format.LogParts, 256)
+		server, err := bootServer(testCase.Output, ch)
+		defer server.Kill()
+
+		if err != nil {
+			t.Errorf("Test #%d: expected no error during syslog server boot, got: %v", i, err)
+		}
+
+		logger := Logger{Output: testCase.Output, fileMu: new(sync.RWMutex)}
+
+		if err := logger.Start(); err != nil {
+			t.Errorf("Test #%d: expected no error during logger start, got: %v", i, err)
+		}
+
+		defer logger.Close()
+
+		logger.Print(testCase.ExpectedOutput)
+
+		actual := <-ch
+
+		if content, ok := actual["content"].(string); ok {
+			if !strings.Contains(content, testCase.ExpectedOutput) {
+				t.Errorf("Test #%d: expected server to capture content: %s, but got: %s", i, testCase.ExpectedOutput, content)
+			}
+		} else {
+			t.Errorf("Test #%d: expected server to capture content but got: %v", i, actual)
+		}
+	}
+}
+
+func bootServer(location string, ch chan format.LogParts) (*syslog.Server, error) {
+	address := parseSyslogAddress(location)
+
+	if address == nil {
+		return nil, fmt.Errorf("Could not parse syslog address: %s", location)
+	}
+
+	server := syslog.NewServer()
+	server.SetFormat(syslog.Automatic)
+
+	switch address.network {
+	case "tcp":
+		server.ListenTCP(address.address)
+	case "udp":
+		server.ListenUDP(address.address)
+	}
+
+	server.SetHandler(syslog.NewChannelHandler(ch))
+
+	if err := server.Boot(); err != nil {
+		return nil, err
+	}
+
+	return server, nil
+}
+
+func captureStdout(f func()) string {
+	original := os.Stdout
+	r, w, _ := os.Pipe()
+
+	os.Stdout = w
+
+	f()
+
+	w.Close()
+
+	written, _ := ioutil.ReadAll(r)
+	os.Stdout = original
+
+	return string(written)
+}
+
+func captureStderr(f func()) string {
+	original := os.Stderr
+	r, w, _ := os.Pipe()
+
+	os.Stderr = w
+
+	f()
+
+	w.Close()
+
+	written, _ := ioutil.ReadAll(r)
+	os.Stderr = original
+
+	return string(written)
+}