Add `/_dendrite/admin/purgeRoom/{roomID}` (#2662)

This adds a new admin endpoint `/_dendrite/admin/purgeRoom/{roomID}`. It
completely erases all database entries for a given room ID.

The roomserver will start by clearing all data for that room and then
will generate an output event to notify downstream components (i.e. the
sync API and federation API) to do the same.

It does not currently clear media and it is currently not implemented
for SQLite since it relies on SQL array operations right now.

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
Co-authored-by: Till Faelligen <2353100+S7evinK@users.noreply.github.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/syncapi/storage/postgres/memberships_table.go b/syncapi/storage/postgres/memberships_table.go
index ac44b235..47833893 100644
--- a/syncapi/storage/postgres/memberships_table.go
+++ b/syncapi/storage/postgres/memberships_table.go
@@ -65,18 +65,22 @@ const selectMembershipCountSQL = "" +
 const selectMembershipBeforeSQL = "" +
 	"SELECT membership, topological_pos FROM syncapi_memberships WHERE room_id = $1 and user_id = $2 AND topological_pos <= $3 ORDER BY topological_pos DESC LIMIT 1"
 
+const purgeMembershipsSQL = "" +
+	"DELETE FROM syncapi_memberships WHERE room_id = $1"
+
 const selectMembersSQL = `
-SELECT event_id FROM (
-	SELECT DISTINCT ON (room_id, user_id) room_id, user_id, event_id, membership FROM syncapi_memberships WHERE room_id = $1 AND topological_pos <= $2 ORDER BY room_id, user_id, stream_pos DESC  
-) t 
-WHERE ($3::text IS NULL OR t.membership = $3)
-	AND ($4::text IS NULL OR t.membership <> $4)
+	SELECT event_id FROM (
+		SELECT DISTINCT ON (room_id, user_id) room_id, user_id, event_id, membership FROM syncapi_memberships WHERE room_id = $1 AND topological_pos <= $2 ORDER BY room_id, user_id, stream_pos DESC  
+	) t 
+	WHERE ($3::text IS NULL OR t.membership = $3)
+		AND ($4::text IS NULL OR t.membership <> $4)
 `
 
 type membershipsStatements struct {
 	upsertMembershipStmt        *sql.Stmt
 	selectMembershipCountStmt   *sql.Stmt
 	selectMembershipForUserStmt *sql.Stmt
+	purgeMembershipsStmt        *sql.Stmt
 	selectMembersStmt           *sql.Stmt
 }
 
@@ -90,6 +94,7 @@ func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
 		{&s.upsertMembershipStmt, upsertMembershipSQL},
 		{&s.selectMembershipCountStmt, selectMembershipCountSQL},
 		{&s.selectMembershipForUserStmt, selectMembershipBeforeSQL},
+		{&s.purgeMembershipsStmt, purgeMembershipsSQL},
 		{&s.selectMembersStmt, selectMembersSQL},
 	}.Prepare(db)
 }
@@ -139,6 +144,13 @@ func (s *membershipsStatements) SelectMembershipForUser(
 	return membership, topologyPos, nil
 }
 
+func (s *membershipsStatements) PurgeMemberships(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeMembershipsStmt).ExecContext(ctx, roomID)
+	return err
+}
+
 func (s *membershipsStatements) SelectMemberships(
 	ctx context.Context, txn *sql.Tx,
 	roomID string, pos types.TopologyToken,