Adding "connection-name" optional parameter (#15)

* Adding "connection-name" optional parameter
Updating on poetry installation steps, README.md, and requirements to support Django 1.11+
* Changes from feedback: correction of source for DEFAULT_DB_ALIAS
Additional tweaks to provide convenient access to the connection_name parameter
Setting min Django version to 1.11.17 since that's the first version supporting Python 3.7
* Bump version to 0.2.0
* Update poetry.lock

Dockerfile

@@ -1,9 +1,9 @@
-FROM python:3
+FROM python:3.9
 
 WORKDIR /code
 
 RUN pip install --upgrade pip
 
 # Install and setup Poetry
-RUN curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -
-RUN echo export PATH=\$PATH:\$HOME/.poetry/bin >> /root/.bashrc
+RUN curl -sSL https://install.python-poetry.org | python3 -
+RUN echo export PATH=\$PATH:\$HOME/.local/bin >> /root/.bashrc

README.md

@@ -27,10 +27,6 @@ Django commands to help with running Django migrations.
 
 Shows existing migration records in your `django_migration` table.
 
-#### Optional parameters:
-
-  * `--format (console | csv)` print the info in CSV or friendlier console format (default)
-
 ```
 > python manage.py migration_records --format csv
 ID,Applied,App,Name
@@ -50,6 +46,10 @@ These are the records of migrations applied. The fields indicate:
   * App - name of the Django app
   * Name - name of the migration 
 
+#### Optional parameters:
+
+  * `--format (console | csv)` print the info in CSV or friendlier console format (default)
+  * `--connection-name {connection}` the connection name to use (default is `django.db.DEFAULT_DB_ALIAS`)
 
 ### migration_current_id
 
@@ -62,6 +62,10 @@ Shows the ID of the latest migration record in your `django_migration` table.
 
 192 is the ID of the latest record as shown above.
 
+#### Optional parameters:
+
+  * `--connection-name {connection}` the connection name to use (default is `django.db.DEFAULT_DB_ALIAS`)
+
 ### migration_rollback
 
 Roll-back (unapply) previously applied migrations _after_ (but not including) the migration ID provided.
@@ -116,6 +120,7 @@ Running migrations:
 
 #### Optional parameters:
 
+  * `--connection-name {connection}` the connection name to use (default is `django.db.DEFAULT_DB_ALIAS`)
   * `--dry-run` will print the commands but will not actually run them
   * `--migrate-cmd <command to run migrations>` sets the command to run migrations with. The command must accept 
     the app and migration name as the `{app}` and `{name}` placeholders, respectively.  
@@ -162,9 +167,8 @@ To delete without confirmation, use the `--yes` option:
 python manage.py migration_delete myapp 0003_some_migration --yes
 ```
 
-
 #### Optional parameters:
-
+  * `--connection-name {connection}` the connection name to use (default is `django.db.DEFAULT_DB_ALIAS`)
   * `--yes` will proceed to deleting the record without asking for confirmation
 
 

docker-compose.yml

@@ -1,10 +1,8 @@
 version: "3.9"
 
 # To build image and initialize container for subsequent tasks:
-#   docker-compose build
+#   docker-compose build --no-cache
 #   docker-compose run --rm buildenv /bin/bash
-#   curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/install-poetry.py | python -
-#   export PATH="/root/.local/bin:$PATH"
 #   poetry install
 #   poetry run python manage.py migrate
 
@@ -19,10 +17,12 @@ version: "3.9"
 # To Publish (test pypi):
 #   docker-compose run --rm buildenv /bin/bash
 #   poetry config repositories.testpypi https://test.pypi.org/legacy/
+#   poetry config http-basic.testpypi vancly <password>
 #   poetry publish -r testpypi
 
 # To Publish:
 #   docker-compose run --rm buildenv /bin/bash
+#   poetry config http-basic.pypi vancly <password>
 #   poetry publish
 
 services:

main/urls.py

@@ -13,8 +13,6 @@
     1. Import the include() function: from django.urls import include, path
     2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
 """
-from django.contrib import admin
-from django.urls import path
 
 urlpatterns = [
 ]

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "vmigration-helper"
-version = "0.1.2"
+version = "0.2.0"
 homepage = "https://github.com/bluedenim/vmigration-helper"
 description = "Van's Django Migration Helper"
 authors = ["bluedenim <[email protected]>"]
@@ -12,8 +12,8 @@ exclude = ["main"]
 keywords = ["django","migration","rollback"]
 
 [tool.poetry.dependencies]
-python = ">=3.6,<4.0"
-Django = "^3.2.6"
+python = ">=3.7,<4.0"
+Django = "^1.11.17"
 
 [tool.poetry.dev-dependencies]
 twine = "^3.4.1"

vmigration_helper/helpers/command.py

@@ -0,0 +1,51 @@
+from abc import ABC
+
+from django.core.management import BaseCommand
+from django.db import connections, DEFAULT_DB_ALIAS
+from django.db.migrations.recorder import MigrationRecorder
+
+from vmigration_helper.helpers.migration_records import MigrationRecordsHelper
+
+
+class MigrationCommand(BaseCommand, ABC):
+    """
+    Abstract base class for migration commands in this app.
+
+    This class provides a place for common concerns to all migration commands to be implemented. For instance, it
+    registers the "connection-name" optional parameter to the command and surfaces the parameter as
+    the "connection_name" property.
+    """
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--connection-name',
+            default=DEFAULT_DB_ALIAS,
+            help=f'The connection to use for migration commands. Defaults to django.db.DEFAULT_DB_ALIAS'
+        )
+
+    def execute(self, *args, **options):
+        self.connection_name = options["connection_name"]
+        super().execute(*args, **options)
+
+    def create_migration_helper(self, connection=None) -> MigrationRecordsHelper:
+        """
+        Initializes a connection and returns an instance of MigrationRecordsHelper initialized to the connection
+        provided.
+
+        :param connection: optional connection to use. If not provided, a connection to the current connection name
+            is created and used. If a connection is provided, its prepare_database() MUST have been called.
+
+        :returns: an instance of MigrationRecordsHelper
+        """
+        if not connection:
+            connection = connections[self.connection_name]
+            connection.prepare_database()
+        return MigrationRecordsHelper(MigrationRecorder(connection))
+
+    @property
+    def connection_name(self) -> str:
+        return self._connection_name
+
+    @connection_name.setter
+    def connection_name(self, value: str) -> None:
+        self._connection_name = value

vmigration_helper/helpers/migration_records.py

@@ -1,6 +1,6 @@
 from typing import List, Optional
 
-from django.db import DEFAULT_DB_ALIAS, connections
+from django.db import connections, DEFAULT_DB_ALIAS
 from django.db.migrations.recorder import MigrationRecorder
 from django.db.models import QuerySet
 

vmigration_helper/management/commands/migration_current_id.py

@@ -1,31 +1,26 @@
-from django.core.management import BaseCommand
-from django.db import DEFAULT_DB_ALIAS, connections, OperationalError
-from django.db.migrations.recorder import MigrationRecorder
+from django.db import OperationalError
 from django.db.models import Max
 
-from vmigration_helper.helpers.migration_records import MigrationRecordsHelper
+from vmigration_helper.helpers.command import MigrationCommand
 
 
-class Command(BaseCommand):
+class Command(MigrationCommand):
     """
     Displays the ID of the last entry in the migration records (from the ``django_migrations`` table).
     """
 
-    @staticmethod
-    def create_snapshot_name(connection) -> int:
+    def create_snapshot_name(self) -> int:
         """
         Returns the current max ID of the migration records table (django_migrations). If there are no records,
         0 is returned.
         """
-        helper = MigrationRecordsHelper(MigrationRecorder(connection))
+        helper = self.create_migration_helper()
         latest_migration_id = helper.get_migration_records_qs().aggregate(Max('id'))['id__max']
         return latest_migration_id or 0
 
     def handle(self, *args, **options):
         try:
-            connection = connections[DEFAULT_DB_ALIAS]
-            connection.prepare_database()
-            print(self.create_snapshot_name(connection))
+            print(self.create_snapshot_name())
         except OperationalError as e:
             print(f'DB ERROR: {e}')
             exit(1)

vmigration_helper/management/commands/migration_delete.py

@@ -1,11 +1,7 @@
-from django.core.management import BaseCommand
-from django.db import DEFAULT_DB_ALIAS, connections
-from django.db.migrations.recorder import MigrationRecorder
+from vmigration_helper.helpers.command import MigrationCommand
 
-from vmigration_helper.helpers.migration_records import MigrationRecordsHelper
 
-
-class Command(BaseCommand):
+class Command(MigrationCommand):
     """
     Deletes a migration record from django_migrations. This operation is a low-level operation and
     should be used only as a last resort when a migration cannot be rolled back, and deleting a record that is a
@@ -14,6 +10,7 @@ class Command(BaseCommand):
     """
 
     def add_arguments(self, parser):
+        super().add_arguments(parser)
         parser.add_argument(
             'app',
             help=(
@@ -38,11 +35,8 @@ def handle(self, *args, **options):
         app = options['app']
         name = options['name']
         yes = options['yes']
-
         if app and name:
-            connection = connections[DEFAULT_DB_ALIAS]
-            connection.prepare_database()
-            helper = MigrationRecordsHelper(MigrationRecorder(connection))
+            helper = self.create_migration_helper()
 
             if not yes:
                 record = helper.get_migration_records_qs().filter(app=app, name=name)

vmigration_helper/management/commands/migration_records.py

@@ -1,16 +1,15 @@
-from django.core.management import BaseCommand
-from django.db import DEFAULT_DB_ALIAS, connections, OperationalError
+from django.db import OperationalError
 from django.db.migrations.recorder import MigrationRecorder
 from django.db.models import QuerySet
 
-from vmigration_helper.helpers.migration_records import MigrationRecordsHelper
+from vmigration_helper.helpers.command import MigrationCommand
 
 FORMAT_CSV = 'csv'
 FORMAT_CONSOLE = 'console'
 DATETIME_FORMAT = '%Y-%m-%dT%H:%M:%S%z'
 
 
-class Command(BaseCommand):
+class Command(MigrationCommand):
     """
     Displays all the migration records (from the ``django_migrations`` table).
 
@@ -46,6 +45,7 @@ def _find_max_app_name_width(migration_query_set: QuerySet) -> int:
         return 0
 
     def add_arguments(self, parser):
+        super().add_arguments(parser)
         parser.add_argument(
             '--format',
             default=FORMAT_CONSOLE,
@@ -54,11 +54,8 @@ def add_arguments(self, parser):
 
     def handle(self, *args, **options):
         print_format = options['format']
-
         try:
-            connection = connections[DEFAULT_DB_ALIAS]
-            connection.prepare_database()
-            helper = MigrationRecordsHelper(MigrationRecorder(connection))
+            helper = self.create_migration_helper()
             migrations_queryset = helper.get_migration_records_qs().all()
 
             app_name_width = 0

vmigration_helper/management/commands/migration_rollback.py

@@ -1,16 +1,15 @@
 import subprocess
 from typing import List
 
-from django.core.management import BaseCommand
-from django.db import DEFAULT_DB_ALIAS, connections, OperationalError
+from django.db import OperationalError
 from django.db.migrations.recorder import MigrationRecorder
 
-from vmigration_helper.helpers.migration_records import MigrationRecordsHelper
+from vmigration_helper.helpers.command import MigrationCommand
 
 MIGRATE_COMMAND = 'python manage.py migrate {app} {name}'
 
 
-class Command(BaseCommand):
+class Command(MigrationCommand):
     """
     Rolls back migrations by unapplying entries in the migration records (django_migrations) whose IDs are greater
     than the ID provided.
@@ -37,6 +36,7 @@ class Command(BaseCommand):
     """
 
     def add_arguments(self, parser):
+        super().add_arguments(parser)
         parser.add_argument(
             'to_id',
             type=int,
@@ -65,9 +65,7 @@ def handle(self, *args, **options):
         migrate_cmd = options['migrate_cmd']
 
         try:
-            connection = connections[DEFAULT_DB_ALIAS]
-            connection.prepare_database()
-            helper = MigrationRecordsHelper(MigrationRecorder(connection))
+            helper = self.create_migration_helper()
             qs = helper.get_migration_records_qs().filter(id__gt=rollback_to_id).order_by('-id')
             migration_records = list(qs)  # type: List[MigrationRecorder.Migration]
             squashed_migrations = helper.squash_migrations(migration_records)