add postgres executor

.pre-commit-config.yaml

@@ -26,4 +26,4 @@ repos:
       - id: mypy
         args: ['--show-error-codes', '--warn-unused-ignores']
         exclude: 'bin/|docs/|examples/|experimental/|redun_server/|setup.py'
-        additional_dependencies: [types-freezegun, types-python-dateutil, types-requests]
+        additional_dependencies: [types-freezegun, types-python-dateutil, types-requests, types-psycopg2]

redun/__init__.py

@@ -13,6 +13,11 @@
 except (ImportError, ModuleNotFoundError):
     # Skip gcp_batch executor if google-cloud-batch is not installed.
     pass
+try:
+    from redun.executors.postgres import PgExecutor
+except (ImportError, ModuleNotFoundError):
+    # Skip pg executor if psycopg2 is not installed.
+    pass
 from redun.executors.local import LocalExecutor
 from redun.file import Dir, File, ShardedS3Dataset
 from redun.handle import Handle

redun/cli.py

@@ -1378,6 +1378,18 @@ def get_command_parser(self) -> argparse.ArgumentParser:
         )
         server_parser.set_defaults(func=self.server_command)
 
+        # PgExecutor worker spawner
+        pg_executor_parser = subparsers.add_parser(
+            "pg-executor-worker",
+            help="Start worker process for the given executor of type 'pg'.",
+        )
+        pg_executor_parser.add_argument(
+            "name",
+            help="Name or alias of the excutor",
+            default="default",
+        )
+        pg_executor_parser.set_defaults(func=self.pg_executor_command)
+
         return parser
 
     def help_command(self, args: Namespace, extra_args: List[str], argv: List[str]) -> None:
@@ -3096,3 +3108,10 @@ def server_command(self, args: Namespace, extra_args: List[str], argv: List[str]
             env={k: str(v) for (k, v) in compose_env.items() if v is not None},
             shell=True,
         )
+
+    def pg_executor_command(self, args: Namespace, extra_args: List[str], argv: List[str]) -> None:
+        from redun import PgExecutor
+
+        key: str = "executor." + args.name
+        config: Config = setup_config(args.config, repo=args.pull_repo)
+        PgExecutor.run_worker(config[key])