cluster/services/patroni: test takeovers

cluster/services/patroni/create-databases.nix

@@ -49,7 +49,9 @@ in
       user = {
         destroyAfterDays = 0;
         create = user: psqlSecret "${genPassword} ${user}" ''
-          CREATE USER ${user} PASSWORD '@SECRET@';
+          SELECT 'CREATE USER ${user}'
+          WHERE NOT EXISTS (SELECT FROM pg_roles WHERE rolname = '${user}')\gexec
+          ALTER USER ${user} PASSWORD '@SECRET@';
         '';
         destroy = psqlSecret "printenv OBJECT" ''
           DROP USER @SECRET@;
@@ -59,7 +61,11 @@ in
         destroyAfterDays = 30;
         deps = [ "user" ];
         create = db: psql ''
-          CREATE DATABASE ${db} OWNER ${cfg.databases.${db}.owner};
+          SELECT 'CREATE DATABASE ${db} OWNER ${cfg.databases.${db}.owner}'
+          WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '${db}')\gexec
+        '';
+        change = db: psql ''
+          ALTER DATABASE ${db} OWNER TO ${cfg.databases.${db}.owner};
         '';
         destroy = psqlSecret "printenv OBJECT" ''
           DROP DATABASE @SECRET@;

cluster/services/patroni/simulacrum/test-data.nix

@@ -3,12 +3,17 @@
   patroni = lib.mkIf config.simulacrum {
     databases = config.lib.forService "patroni" {
       testdb.owner = "testuser";
+      existingdb.owner = "existinguser";
     };
     users = config.lib.forService "patroni" {
       testuser.locksmith = {
         nodes = config.services.patroni.nodes.haproxy;
         format = "pgpass";
       };
+      existinguser.locksmith = {
+        nodes = config.services.patroni.nodes.haproxy;
+        format = "pgpass";
+      };
     };
   };
 }

cluster/services/patroni/simulacrum/test.nix

@@ -87,5 +87,31 @@ in
         for client in clients:
             client.succeed(f"PGPASSFILE=/run/locksmith/patroni-testuser psql -h ${link.ipv4} -p ${link.portStr} -U testuser -d testdb --command='create table test_table_{client.name} as select * from generate_series(1, 10) as val;'")
             client.fail("PGPASSFILE=/run/locksmith/patroni-testuser psql -h ${link.ipv4} -p ${link.portStr} -U testuser -d postgres --command='select * from dummy;'")
+
+    with subtest("should take over existing databases and users via incandescence"):
+        for cmd in [
+            "drop database existingdb;",
+            "drop user existinguser;",
+            "create database existingdb owner postgres;",
+            "create user existinguser;"
+        ]:
+            clients[0].succeed(f"psql -h ${link.ipv4} -p ${link.portStr} -U postgres --command='{cmd}'")
+
+        for client in clients:
+            client.fail(f"PGPASSFILE=/run/locksmith/patroni-existinguser psql -h ${link.ipv4} -p ${link.portStr} -U existinguser -d existingdb --command='create table test_table_{client.name} as select * from generate_series(1, 10) as val;'")
+
+        consulConfig = json.loads(clients[0].succeed("cat /etc/consul.json"))
+        addr = consulConfig["addresses"]["http"]
+        port = consulConfig["ports"]["http"]
+        setEnv = f"CONSUL_HTTP_ADDR={addr}:{port}"
+        clients[0].succeed(f"{setEnv} consul kv delete --recurse services/incandescence/providers/patroni/formulae/database/existingdb")
+        clients[0].succeed(f"{setEnv} consul kv delete --recurse services/incandescence/providers/patroni/formulae/user/existinguser")
+
+        for node in nodes:
+            node.systemctl("restart incandescence-patroni.target")
+        clients[0].succeed("[[ $(psql -h ${link.ipv4} -p ${link.portStr} -U postgres --tuples-only --csv --command=\"SELECT pg_roles.rolname FROM pg_database JOIN pg_roles ON pg_database.datdba = pg_roles.oid WHERE pg_database.datname = 'existingdb'\") == existinguser ]]")
+        for client in clients:
+            client.succeed(f"PGPASSFILE=/run/locksmith/patroni-existinguser psql -h ${link.ipv4} -p ${link.portStr} -U existinguser -d existingdb --command='create table test_table_{client.name} as select * from generate_series(1, 10) as val;'")
+            client.fail("PGPASSFILE=/run/locksmith/patroni-existinguser psql -h ${link.ipv4} -p ${link.portStr} -U existinguser -d postgres --command='select * from dummy;'")
   '';
 }