added test for log writer

log/logwriter_test.go

@@ -0,0 +1,78 @@
+package log
+
+import (
+    "testing"
+    "os"
+    "io/ioutil"
+    "fmt"
+    "math/rand"
+    "bytes"
+)
+
+func TestFileWriter_Reopen(t *testing.T) {
+    filename := fmt.Sprintf("/tmp/test_%d.log", rand.Int63())
+    t.Logf("Creating file %s", filename)
+
+    writer, err := NewFileWriter(filename, 0644)
+    if err != nil {
+        t.Fatalf("Unable to create test file (%s): %s", filename, err)
+    }
+    defer os.Remove(filename)
+
+    info, err := os.Stat(filename)
+    if err != nil {
+        t.Fatalf("File was not created")
+    }
+
+    if info.Mode() != 0644 {
+        t.Fatalf("File mode must be 0644, but got %#o instead", info.Mode())
+    }
+
+    n, err := writer.Write([]byte("foo bar\n"))
+    if err != nil {
+        t.Fatalf("Unable to write to test file")
+    }
+
+    if n != 8 {
+        t.Fatalf("Number of written bytes must be 8")
+    }
+
+    rotatedFilename := fmt.Sprintf("/tmp/test_rotated_%d.log", rand.Int63())
+    t.Logf("Rotating file to %s", rotatedFilename)
+    os.Rename(filename, rotatedFilename)
+    defer os.Remove(rotatedFilename)
+
+    writer.Reopen()
+
+    info, err = os.Stat(filename)
+    if err != nil {
+        t.Fatalf("File was not re-created after rotation")
+    }
+
+    n, err = writer.Write([]byte("hello world\n"))
+    if err != nil {
+        t.Fatalf("Unable to write to re-created file")
+    }
+
+    if err = writer.Close(); err != nil {
+        t.Fatalf("Error while closing file: %s", err)
+    }
+
+    currentContent, err := ioutil.ReadFile(filename)
+    if err != nil {
+        t.Fatalf("Unable to read file %s", filename)
+    }
+
+    if bytes.Compare(currentContent, []byte("hello world\n")) != 0 {
+        t.Fatalf("Wrong content in file %s (actual: %s, expected: %s)", filename, currentContent, []byte("hello world\n"))
+    }
+
+    rotatedContent, err := ioutil.ReadFile(rotatedFilename)
+    if err != nil {
+        t.Fatalf("Unable to read rotated file %s", rotatedFilename)
+    }
+
+    if bytes.Compare(rotatedContent, []byte("foo bar\n")) != 0 {
+        t.Fatalf("Wrong content in rotated file %s (actual: %s, expected: %s)", rotatedFilename, rotatedContent, []byte("foo bar\n"))
+    }
+}

main.go

@@ -48,7 +48,7 @@ func main() {
         os.Exit(1)
     }
 
-    logWriter, err := log.NewFileWriter(cfg.LogFile, 0660)
+    logWriter, err := log.NewFileWriter(cfg.LogFile, 0644)
     if err != nil {
         fmt.Fprintln(os.Stderr, "Failed to open log file " + cfg.LogFile, err)
         os.Exit(1)