Setup panicwrap

main.go

@@ -6,7 +6,9 @@ import (
 	"log"
 	"os"
 
+	"github.com/ActiveState/tail"
 	"github.com/mitchellh/cli"
+	"github.com/mitchellh/panicwrap"
 )
 
 func main() {
@@ -14,7 +16,79 @@ func main() {
 }
 
 func realMain() int {
-	log.SetOutput(ioutil.Discard)
+	var wrapConfig panicwrap.WrapConfig
+
+	if !panicwrap.Wrapped(&wrapConfig) {
+		// Determine where logs should go in general (requested by the user)
+		logWriter, err := logOutput()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Couldn't setup log output: %s", err)
+			return 1
+		}
+
+		// We always send logs to a temporary file that we use in case
+		// there is a panic. Otherwise, we delete it.
+		logTempFile, err := ioutil.TempFile("", "terraform-log")
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Couldn't setup logging tempfile: %s", err)
+			return 1
+		}
+		logTempFile.Close()
+		defer os.Remove(logTempFile.Name())
+
+		// Tell the logger to log to this file
+		os.Setenv(EnvLog, "1")
+		os.Setenv(EnvLogFile, logTempFile.Name())
+
+		if logWriter != nil {
+			// Start tailing the file beforehand to get the data
+			t, err := tail.TailFile(logTempFile.Name(), tail.Config{
+				Follow:    true,
+				Logger:    tail.DiscardingLogger,
+				MustExist: true,
+			})
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Couldn't setup logging tempfile: %s", err)
+				return 1
+			}
+			go func() {
+				for line := range t.Lines {
+					logWriter.Write([]byte(line.Text + "\n"))
+				}
+			}()
+		}
+
+		// Create the configuration for panicwrap and wrap our executable
+		wrapConfig.Handler = panicHandler(logTempFile)
+		exitStatus, err := panicwrap.Wrap(&wrapConfig)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Couldn't start Terraform: %s", err)
+			return 1
+		}
+
+		// If >= 0, we're the parent, so just exit
+		if exitStatus >= 0 {
+			return exitStatus
+		}
+
+		// We're the child, so just close the tempfile we made in order to
+		// save file handles since the tempfile is only used by the parent.
+		logTempFile.Close()
+	}
+
+	// Call the real main
+	return wrappedMain()
+}
+
+func wrappedMain() int {
+	logOutput, err := logOutput()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error starting Terraform: %s", err)
+		return 1
+	}
+	if logOutput != nil {
+		log.SetOutput(logOutput)
+	}
 
 	// Get the command line args. We shortcut "--version" and "-v" to
 	// just show the version.