Add a config option to enable the debug mode and redirect logging.

README.md

@@ -129,6 +129,10 @@ You can change all available options using `gocode set` command. The config file
 
    A boolean option. If **true**, gocode will try to automatically build out-of-date packages when their source files are modified, in order to obtain the freshest autocomplete results for them. This feature is experimental. Default: **false**.
 
+ - *force-debug-output*
+
+   A string option. If is not empty, gocode will forcefully redirect the logging into that file. Also forces enabling of the debug mode on the server side. Default: "" (empty).
+
 ### Debugging
 
 If something went wrong, the first thing you may want to do is manually start the gocode daemon with a debug mode enabled and in a separate terminal window. It will show you all the stack traces, panics if any and additional info about autocompletion requests. Shutdown the daemon if it was already started and run a new one explicitly with a debug mode enabled:

config.go

@@ -19,15 +19,17 @@ import (
 //-------------------------------------------------------------------------
 
 type config struct {
-	ProposeBuiltins bool   `json:"propose-builtins"`
-	LibPath         string `json:"lib-path"`
-	Autobuild       bool   `json:"autobuild"`
+	ProposeBuiltins  bool   `json:"propose-builtins"`
+	LibPath          string `json:"lib-path"`
+	Autobuild        bool   `json:"autobuild"`
+	ForceDebugOutput string `json:"force-debug-output"`
 }
 
 var g_config = config{
-	ProposeBuiltins: false,
-	LibPath:         "",
-	Autobuild:       false,
+	ProposeBuiltins:  false,
+	LibPath:          "",
+	Autobuild:        false,
+	ForceDebugOutput: "",
 }
 
 var g_string_to_bool = map[string]bool{

server.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"go/build"
 	"log"
@@ -9,11 +10,20 @@ import (
 	"os"
 	"reflect"
 	"runtime"
-	"bytes"
 )
 
 func do_server() int {
 	g_config.read()
+	if g_config.ForceDebugOutput != "" {
+		// forcefully enable debugging and redirect logging into the
+		// specified file
+		*g_debug = true
+		f, err := os.Create(g_config.ForceDebugOutput)
+		if err != nil {
+			panic(err)
+		}
+		log.SetOutput(f)
+	}
 
 	addr := *g_addr
 	if *g_sock == "unix" {

utils.go

@@ -3,14 +3,14 @@ package main
 import (
 	"bytes"
 	"fmt"
+	"go/build"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"sync"
 	"unicode/utf8"
-	"go/build"
 )
 
 // returns truncated 'data' and amount of bytes skipped (for cursor pos adjustment)
@@ -149,30 +149,30 @@ type go_build_context struct {
 
 func pack_build_context(ctx *build.Context) go_build_context {
 	return go_build_context{
-		GOARCH: ctx.GOARCH,
-		GOOS: ctx.GOOS,
-		GOROOT: ctx.GOROOT,
-		GOPATH: ctx.GOPATH,
-		CgoEnabled: ctx.CgoEnabled,
-		UseAllFiles: ctx.UseAllFiles,
-		Compiler: ctx.Compiler,
-		BuildTags: ctx.BuildTags,
-		ReleaseTags: ctx.ReleaseTags,
+		GOARCH:        ctx.GOARCH,
+		GOOS:          ctx.GOOS,
+		GOROOT:        ctx.GOROOT,
+		GOPATH:        ctx.GOPATH,
+		CgoEnabled:    ctx.CgoEnabled,
+		UseAllFiles:   ctx.UseAllFiles,
+		Compiler:      ctx.Compiler,
+		BuildTags:     ctx.BuildTags,
+		ReleaseTags:   ctx.ReleaseTags,
 		InstallSuffix: ctx.InstallSuffix,
 	}
 }
 
 func unpack_build_context(ctx *go_build_context) build.Context {
 	return build.Context{
-		GOARCH: ctx.GOARCH,
-		GOOS: ctx.GOOS,
-		GOROOT: ctx.GOROOT,
-		GOPATH: ctx.GOPATH,
-		CgoEnabled: ctx.CgoEnabled,
-		UseAllFiles: ctx.UseAllFiles,
-		Compiler: ctx.Compiler,
-		BuildTags: ctx.BuildTags,
-		ReleaseTags: ctx.ReleaseTags,
+		GOARCH:        ctx.GOARCH,
+		GOOS:          ctx.GOOS,
+		GOROOT:        ctx.GOROOT,
+		GOPATH:        ctx.GOPATH,
+		CgoEnabled:    ctx.CgoEnabled,
+		UseAllFiles:   ctx.UseAllFiles,
+		Compiler:      ctx.Compiler,
+		BuildTags:     ctx.BuildTags,
+		ReleaseTags:   ctx.ReleaseTags,
 		InstallSuffix: ctx.InstallSuffix,
 	}
 }