BREAKING: Make eduserver/appservice use userapi (#1138)

* BREAKING: Make eduserver/appservice use userapi

This is a breaking change because this PR restructures how the AS API
tracks its position in Kafka streams. Previously, it used the account DB
to store partition offsets. However, this is also being used by `clientapi`
for the same purpose, which is bad (each component needs to store offsets
independently or else you might lose messages across restarts). This PR
changes this behaviour to now store partition offsets in the `appservice`
database.

This means that:
 - Upon restart, the `appservice` component will attempt to replay all
   room events from the beginning of time.
 - An additional table will be created in the appservice database, which
   in and of itself is backwards compatible.

* Return ErrorConflict

1 files changed, 4 insertions, 0 deletions

diff --git a/appservice/storage/postgres/storage.go b/appservice/storage/postgres/storage.go
index 3e12f3a0..03f331d6 100644
--- a/appservice/storage/postgres/storage.go
+++ b/appservice/storage/postgres/storage.go
@@ -27,6 +27,7 @@ import (
 
 // Database stores events intended to be later sent to application services
 type Database struct {
+	sqlutil.PartitionOffsetStatements
 	events eventsStatements
 	txnID  txnStatements
 	db     *sql.DB
@@ -42,6 +43,9 @@ func NewDatabase(dataSourceName string, dbProperties sqlutil.DbProperties) (*Dat
 	if err = result.prepare(); err != nil {
 		return nil, err
 	}
+	if err = result.PartitionOffsetStatements.Prepare(result.db, "appservice"); err != nil {
+		return nil, err
+	}
 	return &result, nil
 }