+ database migrations

.idea/misc.xml

@@ -1,7 +1,10 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.8 (venv)" project-jdk-type="Python SDK" />
-  <component name="PyCharmProfessionalAdvertiser">
-    <option name="shown" value="true" />
-  </component>
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.8 (venv)" project-jdk-type="Python SDK" />
+  <component name="PyCharmProfessionalAdvertiser">
+    <option name="shown" value="true" />
+  </component>
+  <component name="PythonCompatibilityInspectionAdvertiser">
+    <option name="version" value="3" />
+  </component>
 </project>

main.py

@@ -1,6 +1,7 @@
 import flask
 from flask import Flask, request, current_app, url_for, render_template, flash, redirect
 from flask_script import Manager, Shell
+from flask_migrate import Migrate, MigrateCommand
 from jinja2 import Template
 from flask_sqlalchemy import SQLAlchemy
 from datetime import datetime
@@ -12,8 +13,10 @@ app.debug = True
 app.config['SECRET_KEY'] = '0d6e368e-bd0c-11ea-921d-9342d47f60ca'
 app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
 app.config['SQLALCHEMY_DATABASE_URI'] = "sqlite:///db.sqlite"
-manager = Manager(app)
 db = SQLAlchemy(app)
+migrate = Migrate(app,  db)
+manager = Manager(app)
+manager.add_command('db', MigrateCommand)
 
 
 class Category(db.Model):

migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration.

migrations/alembic.ini

@@ -0,0 +1,45 @@
+# A generic, single database configuration.
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

migrations/env.py

@@ -0,0 +1,96 @@
+from __future__ import with_statement
+
+import logging
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+logger = logging.getLogger('alembic.env')
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+from flask import current_app
+config.set_main_option(
+    'sqlalchemy.url',
+    str(current_app.extensions['migrate'].db.engine.url).replace('%', '%%'))
+target_metadata = current_app.extensions['migrate'].db.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url, target_metadata=target_metadata, literal_binds=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+
+    # this callback is used to prevent an auto-migration from being generated
+    # when there are no changes to the schema
+    # reference: http://alembic.zzzcomputing.com/en/latest/cookbook.html
+    def process_revision_directives(context, revision, directives):
+        if getattr(config.cmd_opts, 'autogenerate', False):
+            script = directives[0]
+            if script.upgrade_ops.is_empty():
+                directives[:] = []
+                logger.info('No changes in schema detected.')
+
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix='sqlalchemy.',
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            process_revision_directives=process_revision_directives,
+            **current_app.extensions['migrate'].configure_args
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

migrations/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/60a6132e925b_initial_migration.py

@@ -0,0 +1,70 @@
+"""Initial migration
+
+Revision ID: 60a6132e925b
+Revises: 
+Create Date: 2020-07-03 14:02:01.302923
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '60a6132e925b'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('categories',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=255), nullable=False),
+    sa.Column('slug', sa.String(length=255), nullable=False),
+    sa.Column('created_on', sa.DateTime(), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('feedbacks',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=1000), nullable=False),
+    sa.Column('email', sa.String(length=100), nullable=False),
+    sa.Column('message', sa.Text(), nullable=False),
+    sa.Column('created_on', sa.DateTime(), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('tags',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=255), nullable=False),
+    sa.Column('slug', sa.String(length=255), nullable=False),
+    sa.Column('created_on', sa.DateTime(), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('posts',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('title', sa.String(length=255), nullable=False),
+    sa.Column('slug', sa.String(length=255), nullable=False),
+    sa.Column('content', sa.Text(), nullable=False),
+    sa.Column('created_on', sa.DateTime(), nullable=True),
+    sa.Column('updated_on', sa.DateTime(), nullable=True),
+    sa.Column('category_id', sa.Integer(), nullable=True),
+    sa.ForeignKeyConstraint(['category_id'], ['categories.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('post_tags',
+    sa.Column('post_id', sa.Integer(), nullable=True),
+    sa.Column('tag_id', sa.Integer(), nullable=True),
+    sa.ForeignKeyConstraint(['post_id'], ['posts.id'], ),
+    sa.ForeignKeyConstraint(['tag_id'], ['tags.id'], )
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('post_tags')
+    op.drop_table('posts')
+    op.drop_table('tags')
+    op.drop_table('feedbacks')
+    op.drop_table('categories')
+    # ### end Alembic commands ###

requirements.txt

@@ -4,3 +4,4 @@ Flask-Script==2.0.6
 email_validator==1.1.1
 Flask_SQLAlchemy==2.4.3
 SQLAlchemy==1.3.18
+flask-migrate==2.5.3