Allow reconnecting to PG connection pool

Author: aaronfriedman6

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## v0.0.4 - 2/13
+- In PostgreSQLClient, allow reconnecting after `close_connection` has been called
+- Updated README with deployment information
+
 ## v0.0.3 - 2/10
 
 - Added GitHub Actions workflow for deploying to production

README.md

@@ -8,7 +8,7 @@ This package contains common Python utility classes and functions.
 * Decrypting values with KMS
 * Encoding and decoding records using a given Avro schema
 * Connecting to and querying a MySQL database
-* Connecting to and querying a PostgreSQL database
+* Connecting to and querying a PostgreSQL database using a connection pool
 * Connecting to and querying Redshift
 
 ## Functions
@@ -28,4 +28,23 @@ pip install '.[tests]'
 deactivate && source testenv/bin/activate
 ```
 
-Add any new dependencies required by code in the `nypl_py_utils` directory to the `dependencies` section of `pyproject.toml`. Add dependencies only required by code in the `tests` directory to the `[project.optional-dependencies]` section.
+Add any new dependencies required by code in the `nypl_py_utils` directory to the `dependencies` section of `pyproject.toml`. Add dependencies only required by code in the `tests` directory to the `[project.optional-dependencies]` section.
+
+## Git workflow
+This repo uses the [Main-QA-Production](https://github.com/NYPL/engineering-general/blob/main/standards/git-workflow.md#main-qa-production) git workflow.
+
+[`main`](https://github.com/NYPL/python-utils/tree/main) has the latest and greatest commits, [`qa`](https://github.com/NYPL/python-utils/tree/qa) has what's in our QA environment, and [`production`](https://github.com/NYPL/python-utils/tree/production) has what's in our production environment.
+
+### Ideal Workflow
+- Cut a feature branch off of `main`
+- Commit changes to your feature branch
+- File a pull request against `main` and assign a reviewer (who must be an owner)
+  - In order for the PR to be accepted, it must pass all unit tests, have no lint issues, and update the CHANGELOG (or contain the `Skip-Changelog` label in GitHub)
+- After the PR is accepted, merge into `main`
+- Merge `main` > `qa`
+- Deploy app to QA on GitHub and confirm it works
+- Merge `qa` > `production`
+- Deploy app to production on GitHub and confirm it works
+
+## Deployment
+The utils repo is deployed as a PyPI package [here](https://pypi.org/project/nypl-py-utils/) and as a Test PyPI package for QA purposes [here](https://test.pypi.org/project/nypl-py-utils/). To deploy to Test PyPI, create a new release in GitHub and tag it `qa-vX.X.X`. The GitHub Actions deploy-qa workflow will then build and publish the package. To deploy to production PyPI, create a release and tag it `production-vX.X.X`.

src/nypl_py_utils/classes/postgresql_client.py

@@ -14,11 +14,14 @@ def __init__(self, host, port, db_name, user, password, **kwargs):
         self.db_name = db_name
         self.timeout = kwargs.get('timeout', 300)
 
-        conn_info = 'postgresql://{user}:{password}@{host}:{port}/{db_name}'\
-            .format(user=user, password=password, host=host, port=port,
-                    db_name=db_name)
+        self.conn_info = ('postgresql://{user}:{password}@{host}:{port}/'
+                          '{db_name}').format(user=user, password=password,
+                                              host=host, port=port,
+                                              db_name=db_name)
+        self.min_size = kwargs.get('min_size', 1)
+        self.max_size = kwargs.get('max_size', None)
         self.pool = ConnectionPool(
-            conn_info, open=False,
+            self.conn_info, open=False,
             min_size=kwargs.get('min_size', 1),
             max_size=kwargs.get('max_size', None))
 
@@ -29,6 +32,10 @@ def connect(self):
         """
         self.logger.info('Connecting to {} database'.format(self.db_name))
         try:
+            if self.pool is None:
+                self.pool = ConnectionPool(
+                    self.conn_info, open=False, min_size=self.min_size,
+                    max_size=self.max_size)
             self.pool.open(wait=True, timeout=self.timeout)
         except psycopg.Error as e:
             self.logger.error(
@@ -67,6 +74,7 @@ def close_connection(self):
         self.logger.debug('Closing {} database connection'.format(
             self.db_name))
         self.pool.close()
+        self.pool = None
 
 
 class PostgreSQLClientError(Exception):

tests/test_postgresql_client.py

@@ -33,7 +33,7 @@ def test_init_with_kwargs(self):
 
     def test_connect(self, test_instance):
         test_instance.connect()
-        test_instance.pool.open.assert_called_once()
+        test_instance.pool.open.assert_called_once_with(wait=True, timeout=300)
 
     def test_connect_with_exception(self):
         test_instance = PostgreSQLClient(
@@ -61,4 +61,12 @@ def test_execute_query(self, test_instance, mocker):
     def test_close_connection(self, test_instance):
         test_instance.connect()
         test_instance.close_connection()
-        test_instance.pool.close.assert_called_once()
+        assert test_instance.pool is None
+
+    def test_reopen_connection(self, test_instance, mocker):
+        test_instance.connect()
+        test_instance.close_connection()
+        test_instance.connect()
+        test_instance.pool.open.assert_has_calls([
+            mocker.call(wait=True, timeout=300),
+            mocker.call(wait=True, timeout=300)])