Add versioning based on Git revisions. This provides a fast way to form…

Add versioning based on Git revisions. This provides a fast way to form Javascript versions that will be consistent when multiservers try to form versioned files.

compress/utils.py

@@ -37,6 +37,17 @@ def get_mod_func(callback):
     except ValueError:
         return callback, ''
     return callback[:dot], callback[dot+1:]
+    
+def get_hexdigest(plaintext):
+    """
+    Create a hexdigest from a plaintext string
+    """
+    try:
+        import hashlib
+        return hashlib.sha1(plaintext).hexdigest()
+    except ImportError:
+        import sha
+        return sha.new(plaintext).hexdigest()
 
 def needs_update(output_file, source_files, verbosity=0):
     """

compress/versioning/git/__init__.py

+import os
+
+from compress.conf import settings
+from compress.utils import get_output_filename, get_hexdigest, compress_source
+from compress.versioning.base import VersioningBase, VersioningError
+
+try:
+    import git
+except ImportError:
+    raise VersioningError("Must have GitPython package installed to use git versioning")
+    
+class GitVersioningBase(VersioningBase):
+    def needs_update(self, output_file, source_files, version):
+        output_file_name = get_output_filename(output_file, version)
+        ph = settings.COMPRESS_VERSION_PLACEHOLDER
+        of = output_file
+        try:
+            phi = of.index(ph)
+            old_version = output_file_name[phi:phi+len(ph)-len(of)]
+            return (version != old_version), version
+        except ValueError:
+            # no placeholder found, do not update, manual update if needed
+            return False, version
+
+class GitRevVersioning(GitVersioningBase):
+    """
+    Version as hash of revision of all files in sources_files list.
+    """
+    def get_version(self, source_files):
+        repo = git.Repo(compress_source(source_files[0]))
+        kwargs = {'max_count' : 1}
+        commit_revs = []
+        for f in source_files:
+            commit = [i for i in repo.iter_commits(paths=compress_source(f), **kwargs)][0]
+            commit_revs.append(commit.name_rev)
+        return get_hexdigest(', '.join(commit_revs))[0:16]
+
+class GitHeadRevVersioning(GitVersioningBase):
+    """
+    Version as hash of latest revision in HEAD. Assumes all sources_files in same git repo.
+    """
+    def get_version(self, source_files):
+        f = source_files[0]
+        repo = git.Repo(compress_source(f))
+        return get_hexdigest(repo.head.commit.name_rev)[0:16]
\ No newline at end of file

docs/Versioning.textile

@@ -26,6 +26,33 @@ To generate SHA-1 version strings, put this in your settings.py:
 COMPRESS_VERSIONING = 'compress.versioning.hash.SHA1Versioning'
 </code></pre>
 
+h3. Git version strings
+
+Versions formed on git revisions in codebase. Provides a fast way to check if any of your files changed that
+will be consistent across multiple web servers so that they all generate the same version numbers for each
+set of source files, assuming their git repositories are all in sync.
+
+Assumes deployment is git repositiory. Requires GitPython 0.2.0. 
+GitPython 0.3.0 uses an async library that does not currently play well with Django. To install using Git just do
+pip install GitPython==0.2.0-beta1.
+
+h4. Git revision version strings.
+
+To generate versions based on revision of every file in your source file list, put this in your settings.py:
+
+<pre><code>
+COMPRESS_VERSIONING = 'compress.versioning.git.GitVersioningBase'
+</code></pre>
+
+h4.Git HEAD last revision version strings.
+
+To generate versions based on the latest revision of HEAD in your git repository (which assumes all of your source files are in the
+same repository), put this in your settings.py:
+
+<pre><code>
+COMPRESS_VERSIONING = 'compress.versioning.git.GitHeadRevVersioning'
+</code></pre>
+
 h3. Write your own versioning class
 
 To write your own versioning class, you can subclass one of the available versioning classes.