Add facilities for managing dev Postgres instances (#354)

This helps the project move away from sqlite and in more of a
"we use postgres" mindset with easy to use commands to make
onboarding for new devs without docker as easy as possible.

.gitignore

@@ -19,5 +19,6 @@ venv3/
 .env
 htmlcov/
 .DS_Store
+pgdb/
 node_modules/
 .python-version

README.md

@@ -108,7 +108,13 @@ The following was tested on a fresh installation of Ubuntu 20.04.
     source venv/bin/activate
     pip install -r requirements.txt
 
-    # Review your settings
+    # Create a development database server
+    python manage.py make_db
+
+    # Start the development database server
+    python manage.py start_db
+
+    # Review your settings, including the database settings from the output from make_db.
     cp fm_eventmanager/settings.py.devel fm_eventmanager/settings.py
 
     python manage.py migrate

fm_eventmanager/settings.py.devel

@@ -130,12 +130,19 @@ WSGI_APPLICATION = 'fm_eventmanager.wsgi.application'
 # Database
 # https://docs.djangoproject.com/en/3.2/ref/settings/#databases
 
+# Remove this class and replace 'HOST' in DATABASES['default']
+# with the output from `python manage.py make_db` or replace
+# with your own Postgres server configuration.
+class _ReadTheREADME:
+    pass
+
 DATABASES = {
     'default': {
-        'ENGINE' : 'django.db.backends.sqlite3',
-        'NAME' : os.path.join(BASE_DIR, 'db.sqlite3'),
+        'ENGINE': 'django.db.backends.postgresql',
+        'HOST': _ReadTheREADME,
+        'NAME' : 'apis_dev',
         'TEST' : {
-            'NAME' : os.path.join(BASE_DIR, 'test-db.sqlite3'),
+            'NAME' : 'apis_test',
         }
     }
 }

registration/management/commands/make_db.py

@@ -0,0 +1,111 @@
+from pathlib import Path
+
+from django.conf import settings
+from django.core.management.base import BaseCommand
+
+from registration.utils.database import DatabaseStatus, Postgres
+
+
+config_block = """
+DATABASES = {{
+    'default': {{
+        'ENGINE': 'django.db.backends.postgresql',
+        'HOST': '{db_path}',
+        'NAME' : '{db_name}',
+    }}
+}}
+"""
+
+config_block_with_test = """
+DATABASES = {{
+    'default': {{
+        'ENGINE': 'django.db.backends.postgresql',
+        'HOST': '{db_path}',
+        'NAME' : '{db_name}',
+        'TEST' : {{
+            'NAME' : '{test_db_name}',
+        }}
+    }}
+}}
+"""
+
+
+class Command(BaseCommand):
+    help = "Creates a development postgresql database."
+
+    def add_arguments(self, parser):
+        base_dir = Path(settings.BASE_DIR)
+        db_dir = (base_dir / "pgdb").absolute()
+
+        parser.add_argument(
+            "--db-path",
+            type=str,
+            default=str(db_dir),
+            help=f"Path where the postgresql database will be created, default {db_dir}.",
+        )
+        parser.add_argument(
+            "--db-name",
+            type=str,
+            default="apis_dev",
+            help="The database name to create, default apis_dev.",
+        )
+        parser.add_argument(
+            "--test-db-name",
+            type=str,
+            default="apis_test",
+            help="The test database name to create, default apis_test.",
+        )
+        parser.add_argument(
+            "--skip-test-db",
+            type=bool,
+            default=False,
+            help="Whether or not to skip creating the test database, default False.",
+        )
+        parser.add_argument(
+            "--silent",
+            type=bool,
+            default=False,
+            help="Whether to suppress configuration information, default False."
+        )
+
+    def handle(self, *args, **options):
+        postgres = Postgres(options["db_path"])
+
+        status = postgres.get_status()
+
+        if status in (DatabaseStatus.UNKNOWN, DatabaseStatus.INVALID_DIRECTORY):
+            postgres.delete()
+
+            status = DatabaseStatus.DOES_NOT_EXIST
+
+        if status in (DatabaseStatus.DOES_NOT_EXIST, DatabaseStatus.DIRECTORY_EMPTY):
+            postgres.init()
+
+            status = DatabaseStatus.STOPPED
+
+        db_name = options["db_name"]
+        postgres.create_db(db_name)
+
+        skip_test_db = options["skip_test_db"]
+        test_db_name = options["test_db_name"]
+        if test_db_name and not skip_test_db:
+            postgres.create_db(test_db_name)
+
+        if options["silent"]:
+            return
+
+        if test_db_name and not skip_test_db:
+            config_text = config_block_with_test.format(
+                db_path=postgres.db_path,
+                db_name=db_name,
+                test_db_name=test_db_name,
+            )
+        else:
+            config_text = config_block.format(
+                db_path=postgres.db_path,
+                db_name=db_name,
+            )
+
+        print(f"Created database {db_name} at {postgres.db_path}")
+        print("Add the following to your settings.py")
+        print(config_text)

registration/management/commands/start_db.py

@@ -0,0 +1,35 @@
+from pathlib import Path
+import sys
+
+from django.conf import settings
+from django.core.management.base import BaseCommand
+
+from registration.utils.database import DatabaseStatus, Postgres
+
+
+class Command(BaseCommand):
+    help = "Starts the development postgresql database."
+
+    def add_arguments(self, parser):
+        base_dir = Path(settings.BASE_DIR)
+        db_dir = (base_dir / "pgdb").absolute()
+
+        parser.add_argument(
+            "--db-path",
+            type=str,
+            default=str(db_dir),
+            help=f"Path where the postgresql database will be stopped, default {db_dir}.",
+        )
+
+    def handle(self, *args, **options):
+        postgres = Postgres(options["db_path"])
+
+        status = postgres.get_status()
+        if status == DatabaseStatus.STOPPED:
+            postgres.start()
+
+            print("Postgres server started")
+        elif status == DatabaseStatus.RUNNING:
+            print("Postgres server is already running")
+        else:
+            print(f"Cannot start Postgres server, invalid status: {status}", file=sys.stderr)

registration/management/commands/stop_db.py

@@ -0,0 +1,37 @@
+from pathlib import Path
+
+from django.conf import settings
+from django.core.management.base import BaseCommand
+
+from registration.utils.database import DatabaseStatus, Postgres
+
+
+class Command(BaseCommand):
+    help = "Stops the development postgresql database."
+
+    def add_arguments(self, parser):
+        base_dir = Path(settings.BASE_DIR)
+        db_dir = (base_dir / "pgdb").absolute()
+
+        parser.add_argument(
+            "--db-path",
+            type=str,
+            default=str(db_dir),
+            help=f"Path where the postgresql database will be stopped, default {db_dir}.",
+        )
+        parser.add_argument(
+            "--delete",
+            type=bool,
+            default=False,
+            help="Whether or not to delete the database after it has been stopped, default False."
+        )
+
+    def handle(self, *args, **options):
+        postgres = Postgres(options["db_path"])
+
+        status = postgres.get_status()
+        if status == DatabaseStatus.RUNNING:
+            postgres.stop()
+
+        if options["delete"]:
+            postgres.delete()