nmhive.py: Use notmuch behind GET /tags

I stick with the NMBPREFIX environment variable for consistency with
nmbug itself.  I also drop 'app.debug = True', to avoid trouble like:

  $ ./nmhive.py
   * Running on http://0.0.0.0:5000/
   * Restarting with reloader
  A Xapian exception occurred opening database: Unable to get write
    lock on /.../xapian: already locked
  Traceback (most recent call last):
    File "./nmhive.py", line 83, in <module>
      mode=notmuch.Database.MODE.READ_WRITE)
    File "/.../notmuch/database.py", line 154, in __init__
      self.open(path, mode)
    File "/.../notmuch/database.py", line 214, in open
      raise NotmuchError(status)
  notmuch.errors.XapianError

because with 'debug = True', Flask tries to run two instances of this
process simultaneously, but only one can hold the write lock at a
time.  If we want to scale this up to multiple writing
threads/processes, we'll probably want to make the persistant Database
instance read-only, and either acquire a write lock as necessary, or
just instantiate a read/write database for each PUT.  For now, it's
easy enough to just have a single thread.

diff --git a/nmhive.py b/nmhive.py
index 23bd4999c81e008770dcacb88bc313edee7fa115..2acde49ee400ee5339f5c86b8f7693783d843e3b 100755 (executable)
--- a/nmhive.py
+++ b/nmhive.py
@@ -2,31 +2,32 @@
 
 import json
 import mailbox
+import os
 import tempfile
 import urllib.request
 
 import flask
 import flask_cors
+import notmuch
 
 
 app = flask.Flask(__name__)
 app.config['CORS_HEADERS'] = 'Content-Type'
 flask_cors.CORS(app)
 
-
-_AVAILABLE_TAGS = {
-    'bug',
-    'needs-review',
-    'obsolete',
-    'patch',
-    }
+TAG_PREFIX = os.getenv('NMBPREFIX', 'notmuch::')
+NOTMUCH = None
 _TAGS = {}
 
 
 @app.route('/tags', methods=['GET'])
 def tags():
+    tags = set()
+    for t in NOTMUCH.get_all_tags():
+        if t.startswith(TAG_PREFIX):
+            tags.add(t[len(TAG_PREFIX):])
     return flask.Response(
-        response=json.dumps(sorted(_AVAILABLE_TAGS)),
+        response=json.dumps(sorted(tags)),
         mimetype='application/json')
 
 
@@ -76,5 +77,7 @@ def gmane_message_id(group, article):
 
 
 if __name__ == '__main__':
-    app.debug = True
+    NOTMUCH = notmuch.Database(
+        path=None,
+        mode=notmuch.Database.MODE.READ_WRITE)
     app.run(host='0.0.0.0')