sync: pull out sync tools logic

cmd/juju/synctools.go

 // Copyright 2013 Canonical Ltd.
 // Licensed under the AGPLv3, see LICENCE file for details.
 
 package main
 
 import (
         "launchpad.net/gnuflag"
+        "launchpad.net/loggo"
+
         "launchpad.net/juju-core/cmd"
         "launchpad.net/juju-core/environs/sync"
 )
 
 var syncTools = sync.SyncTools
 
 // SyncToolsCommand copies all the tools from the us-east-1 bucket to the local
 // bucket.
 type SyncToolsCommand struct {
         EnvCommandBase
         allVersions  bool
         dryRun       bool
         publicBucket bool
         dev          bool
         source       string
 }
 
 var _ cmd.Command = (*SyncToolsCommand)(nil)
 
 func (c *SyncToolsCommand) Info() *cmd.Info {
         return &cmd.Info{
                 Name:    "sync-tools",
                 Purpose: "copy tools from the official bucket into a local environment",
                 Doc: `
 This copies the Juju tools tarball from the official bucket into
 your environment. This is generally done when you want Juju to be able
 to run without having to access Amazon. Alternatively you can specify
 a local directory as source.
 
-Sometimes this is because the environment does not have public access, 
-and sometimes you just want to avoid having to access data outside of 
+Sometimes this is because the environment does not have public access,
+and sometimes you just want to avoid having to access data outside of
 the local cloud.
 `,
         }
 }
 
 func (c *SyncToolsCommand) SetFlags(f *gnuflag.FlagSet) {
         c.EnvCommandBase.SetFlags(f)
         f.BoolVar(&c.allVersions, "all", false, "copy all versions, not just the latest")
         f.BoolVar(&c.dryRun, "dry-run", false, "don't copy, just print what would be copied")
         f.BoolVar(&c.dev, "dev", false, "consider development versions as well as released ones")
         f.BoolVar(&c.publicBucket, "public", false, "write to the public-bucket of the account, instead of the bucket private to the environment.")
         f.StringVar(&c.source, "source", "", "chose a location on the file system as source")
 
         // BUG(lp:1163164)  jam 2013-04-2 we would like to add a "source"
         // location, rather than only copying from us-east-1
 }
 
 func (c *SyncToolsCommand) Init(args []string) error {
         return cmd.CheckEmpty(args)
 }
 
 func (c *SyncToolsCommand) Run(ctx *cmd.Context) error {
+        // Register writer for output on screen.
+        loggo.RegisterWriter("synctools", sync.NewSyncLogWriter(ctx.Stdout, ctx.Stderr), loggo.INFO)
+        defer loggo.RemoveWriter("synctools")
+        // Prepare syncing.
         sctx := &sync.SyncContext{
                 EnvName:      c.EnvName,
                 AllVersions:  c.allVersions,
                 DryRun:       c.dryRun,
                 PublicBucket: c.publicBucket,
                 Dev:          c.dev,
                 Source:       c.source,
-                Stdout:       ctx.Stdout,
-                Stderr:       ctx.Stderr,
         }
         return syncTools(sctx)
 }