From 46511c257999b1c5bdfa02a1ae7d04ee26ffee8f Mon Sep 17 00:00:00 2001
From: Richard Ipsum <richardipsum@fastmail.co.uk>
Date: Sun, 5 Jul 2015 12:15:55 +0100
Subject: Display progress bar when fetching to local cache

Looks like,

2015-07-05 16:08:10 [Build 1/304] [stage1-binutils] Fetching to local cache: artifact stage1-binutils-misc
stage1-binutils-misc[#####################         ] 51.9/73.0 MB

Change-Id: Ib10f1cfaa0c1df80ae605ecfeb5b706c8d46c4a4
---
 morphlib/buildcommand.py | 34 +++++++++++++++++++++++++++++++---
 morphlib/util.py         | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 3 deletions(-)

diff --git a/morphlib/buildcommand.py b/morphlib/buildcommand.py
index bb354b2f..8b728b05 100644
--- a/morphlib/buildcommand.py
+++ b/morphlib/buildcommand.py
@@ -1,4 +1,6 @@
+# -*- coding: utf-8 -*-
 # Copyright (C) 2011-2015  Codethink Limited
+# Copyright © 2015  Richard Ipsum
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -400,16 +402,42 @@ class BuildCommand(object):
     def cache_artifacts_locally(self, artifacts):
         '''Get artifacts missing from local cache from remote cache.'''
 
-        def fetch_files(to_fetch):
+        def do_fetch(name, remote, local):
+            meta = remote.info()
+            content_len = int(meta.getheaders('Content-Length')[0])
+            logging.debug('Artifact content length: %s', content_len)
+
+            if content_len < 1024:
+                report_progress = lambda count: bar.show(count)
+                expected_size = content_len
+                unit = 'bytes'
+            elif content_len >= 1024 and content_len < 1024 ** 2:
+                report_progress = lambda count: bar.show(count / float(1024))
+                expected_size = content_len / float(1024)
+                unit = 'KB'
+            else:
+                report_progress = lambda count: bar.show(count
+                                                          / float((1024 ** 2)))
+                expected_size = content_len / float((1024 ** 2))
+                unit = 'MB'
+
+            bar = morphlib.util.ProgressBar(name,
+                                            expected_size, unit)
+
+            morphlib.util.copyfileobj(remote, local,
+                                      callback=report_progress)
+
+        def fetch_files(name, to_fetch):
             '''Fetch a set of files atomically.
 
             If an error occurs during the transfer of any files, all downloaded
             data is deleted, to ensure integrity of the local cache.
 
             '''
+
             try:
                 for remote, local in to_fetch:
-                    shutil.copyfileobj(remote, local)
+                    do_fetch(name, remote, local)
             except BaseException:
                 for remote, local in to_fetch:
                     local.abort()
@@ -439,7 +467,7 @@ class BuildCommand(object):
                 self.app.status(
                     msg='Fetching to local cache: artifact %(name)s',
                     name=artifact.name)
-                fetch_files(to_fetch)
+                fetch_files(artifact.name, to_fetch)
 
     def create_staging_area(self, source, build_env, use_chroot=True,
                             extra_env={}, extra_path=[]):
diff --git a/morphlib/util.py b/morphlib/util.py
index a92b7f37..284fe305 100644
--- a/morphlib/util.py
+++ b/morphlib/util.py
@@ -1,4 +1,6 @@
+# -*- coding: utf-8 -*-
 # Copyright (C) 2011-2015  Codethink Limited
+# Copyright © 2015  Richard Ipsum
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -731,3 +733,45 @@ def temp_dir(*args, **kwargs): #pragma: no cover
     else:
         if cleanup_on_success:
             shutil.rmtree(td, ignore_errors=True)
+
+def copyfileobj(fsrc, fdst, length=16*1024,
+                callback=lambda x: None): #pragma: no cover
+    ''' This is similar to shutil.copyfileobj
+        except this can be passed a callback to monitor copy progress
+    '''
+
+    count = 0
+
+    while True:
+        buf = fsrc.read(length)
+        if buf == '':
+            break
+
+        fdst.write(buf)
+        count += len(buf)
+        callback(count)
+
+
+class ProgressBar(object):
+    ''' A very simple progress bar '''
+
+    TEMPLATE = '%s[%s%s] %.1f/%.1f %s\r'
+
+    def __init__(self, label, expected_size, unit, width=30,
+                 progress_char='#', empty_char=' '): #pragma: no cover
+        self._label = label
+        self._expected_size = expected_size
+        self._width = width
+        self._unit = unit
+        self._block_width = expected_size / float(width);
+        self._progress_char = progress_char
+        self._empty_char = empty_char
+
+    def show(self, progress): #pragma: no cover
+        blocks = int(progress / self._block_width);
+
+        s = self.TEMPLATE % (self._label, self._progress_char * blocks,
+                             self._empty_char * (self._width - blocks),
+                             progress, self._expected_size, self._unit)
+        sys.stderr.write(s)
+        sys.stderr.flush()
-- 
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