Implement create_appservice_txn with tests.

synapse/storage/appservice.py

@@ -17,9 +17,10 @@ from simplejson import JSONDecodeError
 import simplejson as json
 from twisted.internet import defer
 
+from syutil.jsonutil import encode_canonical_json
 from synapse.api.constants import Membership
 from synapse.api.errors import StoreError
-from synapse.appservice import ApplicationService, ApplicationServiceState
+from synapse.appservice import ApplicationService, AppServiceTransaction
 from synapse.storage.roommember import RoomsForUser
 from ._base import SQLBaseStore
 
@@ -417,9 +418,46 @@ class ApplicationServiceTransactionStore(SQLBaseStore):
         Returns:
             AppServiceTransaction: A new transaction.
         """
-        # TODO: work out txn id (highest txn id for this service += 1)
-        # TODO: Within same db transaction, Insert new txn into txn table
-        pass
+        return self.runInteraction(
+            "create_appservice_txn",
+            self._create_appservice_txn,
+            service, events
+        )
+
+    def _create_appservice_txn(self, txn, service, events):
+        # work out new txn id (highest txn id for this service += 1)
+        # The highest id may be the last one sent (in which case it is last_txn)
+        # or it may be the highest in the txns list (which are waiting to be/are
+        # being sent)
+        result = txn.execute(
+            "SELECT last_txn FROM application_services_state WHERE as_id=?",
+            (service.id,)
+        )
+        last_txn_id = result.fetchone()
+        if last_txn_id is None:  # no row exists
+            last_txn_id = 0
+        else:
+            last_txn_id = int(last_txn_id[0])  # select 'last_txn' col
+
+        result = txn.execute(
+            "SELECT MAX(txn_id) FROM application_services_txns WHERE as_id=?",
+            (service.id,)
+        )
+        highest_txn_id = result.fetchone()[0]
+        if highest_txn_id is None:
+            highest_txn_id = 0
+
+        new_txn_id = max(highest_txn_id, last_txn_id) + 1
+
+        # Insert new txn into txn table
+        txn.execute(
+            "INSERT INTO application_services_txns(as_id, txn_id, content) "
+            "VALUES(?,?,?)",
+            (service.id, new_txn_id, encode_canonical_json(events))
+        )
+        return AppServiceTransaction(
+            service=service, id=new_txn_id, events=events
+        )
 
     def complete_appservice_txn(self, txn_id, service):
         """Completes an application service transaction.