First cut at git hook. Produces JSON but doesn't yet deliver.

diff --git a/git-irkbot.py b/git-irkbot.py
new file mode 100755 (executable)
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--- /dev/null
+++ b/git-irkbot.py
@@ -0,0 +1,196 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 Eric S. Raymond <esr@thyrsus.com>
+# Distributed under BSD terms.
+#
+# This script contains porcelain and porcelain byproducts.
+# It should be compatible back to Python 2.1.5
+#
+# usage: git-irkbot.py [-V] [-n] [-p projectname]  [refname [commits...]]
+#
+# This script is meant to be run either in a post-commit hook or in an
+# update hook. Try it with -n to see the notification mail dumped to
+# stdout and verify that it looks sane. With -V it dumps its version
+# and exits.
+#
+# In post-commit, run it without arguments. It will query for
+# current HEAD and the latest commit ID to get the information it
+# needs.
+#
+# In update, call it with a refname followed by a list of commits:
+# You want to reverse the order git rev-list emits because it lists
+# from most recent to oldest.
+#
+# /path/to/git-irkbot.py ${refname} $(git rev-list ${oldhead}..${newhead} | tac)
+#
+# Configuration variables affecting this script:
+#
+# irker.project = name of the project
+# irker.channels = list of IRC URLs corresponding to channels
+# irker.repo = name of the project repo for gitweb/cgit purposes
+# irker.revformat = format in which the revision is shown
+# irker.server = location of the irker server to use for relaying
+#
+# irker.channels defaults to a project channel on freenode, and #commits
+# irker.project defaults to the directory name of the repository toplevel.
+# irker.repo defaults to irker.project lowercased.
+#
+# This means that in the normal case you need not do any configuration at all,
+# but setting the project name will speed it up slightly.
+#
+# The revformat variable may have the following values
+# raw -> full hex ID of commit
+# short -> first 12 chars of hex ID
+# describe = -> describe relative to last tag, falling back to short
+# The default is 'describe'.
+
+# The default location of the irker proxy, if the project configuration
+# does not override it.
+default_irker_host = "localhost"
+default_irker_port = 6659
+
+# Changeset URL prefix for your repo: when the commit ID is appended
+# to this, it should point at a CGI that will display the commit
+# through gitweb or something similar. The defaults will probably
+# work if you have a typical gitweb/cgit setup.
+#
+#urlprefix="http://%(host)s/cgi-bin/gitweb.cgi?p=%(repo)s;a=commit;h="
+urlprefix="http://%(host)s/cgi-bin/cgit.cgi/%(repo)s/commit/?id="
+
+# The service used to turn your gitwebbish URL into a tinyurl so it
+# will take up less space on the IRC notification line.
+tinyifier = "http://tinyurl.com/api-create.php?url="
+
+# The template used to generate notifications.  You can make
+# visible changes to the IRC-bot notification lines by hacking this.
+#
+# ${project}: ${author} ${repo}:${branch} * ${rev} / ${files}: ${logmsg} ${url}
+template = '%(project)s: %(author)s %(repo)s:%(branch)s * %(rev)s / %(files)s: %(logmsg)s %(url)s'
+
+#
+# No user-serviceable parts below this line:
+#
+
+import os, sys, commands, socket, urllib, json
+
+# Identify the generator script.
+# Should only change when the script itself gets a new home and maintainer.
+generator = "http://www.catb.org/~esr/irker/git-irkbot.py"
+version = "1.0"
+
+def do(command):
+    return commands.getstatusoutput(command)[1]
+
+def extract(refname, merged):
+    "Extract metadata to be reported to CIA."
+
+    # Try to tinyfy a reference to a web view for this commit.
+    try:
+        url = open(urllib.urlretrieve(tinyifier + urlprefix + merged)[0]).read()
+    except:
+        url = urlprefix + merged
+
+    branch = os.path.basename(refname)
+
+    # Compute a description for the revision
+    if revformat == 'raw':
+        rev = merged
+    elif revformat == 'short':
+        rev = ''
+    else: # revformat == 'describe'
+        rev = do("git describe %s 2>/dev/null" % merged)
+    if not rev:
+        rev = merged[:12]
+
+    # Extract the meta-information for the commit
+    files=do("git diff-tree -r --name-only '"+ merged +"' | sed -e '1d' -e 's-.*-&-'")
+    metainfo = do("git log -1 '--pretty=format:%an <%ae>%n%at%n%s' " + merged)
+    (author, ts, logmsg) = metainfo.split("\n")
+
+    # This discards the part of the author's address after @.
+    # Might be be nice to ship the full email address, if not
+    # for spammers' address harvesters - getting this wrong
+    # would make the freenode #commits channel into harvester heaven.
+    author = author.replace("<", "").split("@")[0].split()[-1]
+
+    # This ignores the timezone.  Not clear what to do with it...
+    ts = ts.strip().split()[0]
+
+    context = locals()
+    context.update(globals())
+
+    return context
+
+if __name__ == "__main__":
+    import getopt
+
+    # Get all config variables
+    revformat = do("git config --get irker.revformat")
+    project = do("git config --get irker.project")
+    repo = do("git config --get irker.repo")
+    server = do("git config --get irker.server")
+    channels = do("git config --get irker.channels")
+
+    host = socket.getfqdn()
+
+    try:
+        (options, arguments) = getopt.getopt(sys.argv[1:], "np:V")
+    except getopt.GetoptError, msg:
+        print "git-irkbot.py: " + str(msg)
+        raise SystemExit, 1
+
+    notify = True
+    for (switch, val) in options:
+        if switch == '-p':
+            project = val
+        elif switch == '-n':
+            notify = False
+        elif switch == '-V':
+            print "git-irkbot.py: version", version
+            sys.exit(0)
+
+    # The project variable defaults to the name of the repository toplevel. 
+    if not project:
+        here = os.getcwd()
+        while True:
+            if os.path.exists(os.path.join(here, ".git")):
+                project = os.path.basename(here)
+                break
+            elif here == '/':
+                sys.stderr.write("git-irkbot.py: no .git below root!\n")
+                sys.exit(1)
+            here = os.path.dirname(here)
+
+    # By default, the channel list includes the freenode #commits list 
+    if not channels:
+        channels = "irc://chat.freenode.net/%s,irc://chat.freenode.net/#commits" % project
+
+    if not repo:
+        repo = project.lower()
+
+    urlprefix = urlprefix % globals()
+
+    # The script wants a reference to head followed by the list of
+    # commit ID to report about.
+    if len(arguments) == 0:
+        refname = do("git symbolic-ref HEAD 2>/dev/null")
+        merges = [do("git rev-parse HEAD")]
+    else:
+        refname = arguments[0]
+        merges = arguments[1:]
+
+    for merged in merges:
+        context = extract(refname, merged)
+        privmsg = template % context
+        channel_list = channels.split(",")
+        structure = {"to":channel_list, "privmsg":privmsg}
+        message = json.dumps(structure)
+        if not notify:
+            print message
+        else:
+            try:
+                # FIXME: Actual delivery must go here. Use the server variable.
+                pass
+            except socket.error, e:
+                sys.stderr.write("%s\n" % e)
+
+#End