Save patches to files before applying

This allows us to minimize the possibility of unicode/bytes issues on
different Python versions and to avoid reading entire patches into
memory.

Signed-off-by: Stephen Finucane <[email protected]>
Fixes: #6

git_pw/api.py

@@ -3,7 +3,9 @@
 """
 
 import logging
+import os
 import sys
+import tempfile
 
 import requests
 
@@ -88,13 +90,14 @@ def _handle_error(operation, exc):
         sys.exit(1)
 
 
-def get(url, params=None):  # type: (str, dict) -> requests.Response
+def get(url, params=None, stream=False):
+    # type: (str, dict, bool) -> requests.Response
     """Make GET request and handle errors."""
     LOG.debug('GET %s', url)
 
     try:
         rsp = requests.get(url, auth=_get_auth(), headers=_get_headers(),
-                           params=params)
+                           params=params, stream=stream)
         rsp.raise_for_status()
     except requests.exceptions.RequestException as exc:
         _handle_error('fetch', exc)
@@ -120,6 +123,31 @@ def put(url, data):  # type: (str, dict) -> requests.Response
     return rsp
 
 
+def download(url, params=None):  # type: (str, dict) -> None
+    """Retrieve a specific API resource and save it to a file.
+
+    GET /{resource}/{resourceID}/
+
+    Arguments:
+        resource_type (str): The resource endpoint name.
+        resource_id (int/str): The ID for the specific resource.
+        params (dict/list): Additional parameters.
+
+    Returns:
+        A path to an output file containing the content.
+    """
+    output_fd, output_path = tempfile.mkstemp(suffix='.patch')
+
+    rsp = get(url, params, stream=True)
+    with os.fdopen(output_fd, 'w') as output_file:
+        LOG.debug('Saving to %s', output_path)
+        # we use iter_content because patches can be binary
+        for block in rsp.iter_content(1024):
+            output_file.write(block)
+
+    return output_path
+
+
 def index(resource_type, params=None):  # type: (str, dict) -> dict
     """List API resources.
 
@@ -164,7 +192,7 @@ def detail(resource_type, resource_id, params=None):
     url = '/'.join([_get_server(), 'api', resource_type,
                     str(resource_id), ''])
 
-    return get(url, params).json()
+    return get(url, params, stream=False).json()
 
 
 def update(resource_type, resource_id, data):

git_pw/bundle.py

@@ -25,7 +25,7 @@ def apply_cmd(bundle_id, args):
     LOG.info('Applying bundle: id=%d', bundle_id)
 
     bundle = api.detail('bundles', bundle_id)
-    mbox = api.get(bundle['mbox']).text
+    mbox = api.download(bundle['mbox']).text
 
     utils.git_am(mbox, args)
 

git_pw/patch.py

@@ -38,7 +38,7 @@ def apply_cmd(patch_id, series, deps, args):
     elif not deps:
         series = None
 
-    mbox = api.get(patch['mbox'], {'series': series}).content
+    mbox = api.download(patch['mbox'], {'series': series})
 
     utils.git_am(mbox, args)
 

git_pw/series.py

@@ -26,7 +26,7 @@ def apply_cmd(series_id, args):
     LOG.info('Applying series: id=%d, args=%s', series_id, ' '.join(args))
 
     series = api.detail('series', series_id)
-    mbox = api.get(series['mbox']).text
+    mbox = api.download(series['mbox'])
 
     utils.git_am(mbox, args)
 

git_pw/utils.py

@@ -20,5 +20,8 @@ def git_am(mbox, args):
         cmd.append('-3')
     cmd.append(mbox)
 
-    p = subprocess.Popen(cmd, stdin=subprocess.PIPE)
-    p.communicate(mbox)
+    try:
+        subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as exc:
+        print(exc.output)
+        sys.exit(exc.returncode)

releasenotes/notes/save-patches-before-applying-c5e786156d47d752.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    The ``git pw {patch,series,bundle} apply`` commands will now save the
+    downloaded patches before applying them. This avoids ascii/unicode issues
+    on different versions of Python and avoids the need to load the entire
+    patch into memory.