From 95282d34be4c25f4402feeac9bd92c4b22f7eae0 Mon Sep 17 00:00:00 2001
From: Miguel Grinberg <miguel.grinberg@gmail.com>
Date: Mon, 11 Sep 2017 14:30:21 -0700
Subject: [PATCH] Chapter 4: Database (v0.4)
---
app/__init__.py | 6 +-
app/models.py | 23 +++++
config.py | 5 ++
microblog.py | 8 +-
migrations/README | 1 +
migrations/alembic.ini | 45 ++++++++++
migrations/env.py | 87 +++++++++++++++++++
migrations/script.py.mako | 24 +++++
.../versions/780739b227a7_posts_table.py | 37 ++++++++
.../versions/e517276bb1c2_users_table.py | 38 ++++++++
10 files changed, 272 insertions(+), 2 deletions(-)
create mode 100644 app/models.py
create mode 100755 migrations/README
create mode 100644 migrations/alembic.ini
create mode 100755 migrations/env.py
create mode 100755 migrations/script.py.mako
create mode 100644 migrations/versions/780739b227a7_posts_table.py
create mode 100644 migrations/versions/e517276bb1c2_users_table.py
diff --git a/app/__init__.py b/app/__init__.py
index f5b34f4..612a972 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -1,7 +1,11 @@
from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from flask_migrate import Migrate
from config import Config
app = Flask(__name__)
app.config.from_object(Config)
+db = SQLAlchemy(app)
+migrate = Migrate(app, db)
-from app import routes
+from app import routes, models
diff --git a/app/models.py b/app/models.py
new file mode 100644
index 0000000..331c9bb
--- /dev/null
+++ b/app/models.py
@@ -0,0 +1,23 @@
+from datetime import datetime
+from app import db
+
+
+class User(db.Model):
+ id = db.Column(db.Integer, primary_key=True)
+ username = db.Column(db.String(64), index=True, unique=True)
+ email = db.Column(db.String(120), index=True, unique=True)
+ password_hash = db.Column(db.String(128))
+ posts = db.relationship('Post', backref='author', lazy='dynamic')
+
+ def __repr__(self):
+ return '<User {}>'.format(self.username)
+
+
+class Post(db.Model):
+ id = db.Column(db.Integer, primary_key=True)
+ body = db.Column(db.String(140))
+ timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
+ user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
+
+ def __repr__(self):
+ return '<Post {}>'.format(self.body)
diff --git a/config.py b/config.py
index 5bf854f..a1f300c 100644
--- a/config.py
+++ b/config.py
@@ -1,4 +1,9 @@
import os
+basedir = os.path.abspath(os.path.dirname(__file__))
+
class Config(object):
SECRET_KEY = os.environ.get('SECRET_KEY') or 'you-will-never-guess'
+ SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
+ 'sqlite:///' + os.path.join(basedir, 'app.db')
+ SQLALCHEMY_TRACK_MODIFICATIONS = False
diff --git a/microblog.py b/microblog.py
index d099b92..3c32c5e 100644
--- a/microblog.py
+++ b/microblog.py
@@ -1 +1,7 @@
-from app import app
+from app import app, db
+from app.models import User, Post
+
+
+@app.shell_context_processor
+def make_shell_context():
+ return {'db': db, 'User': User, 'Post': Post}
diff --git a/migrations/README b/migrations/README
new file mode 100755
index 0000000..98e4f9c
--- /dev/null
+++ b/migrations/README
@@ -0,0 +1 @@
+Generic single-database configuration.
\ No newline at end of file
diff --git a/migrations/alembic.ini b/migrations/alembic.ini
new file mode 100644
index 0000000..f8ed480
--- /dev/null
+++ b/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
diff --git a/migrations/env.py b/migrations/env.py
new file mode 100755
index 0000000..23663ff
--- /dev/null
+++ b/migrations/env.py
@@ -0,0 +1,87 @@
+from __future__ import with_statement
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from logging.config import fileConfig
+import logging
+
+# 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',
+ current_app.config.get('SQLALCHEMY_DATABASE_URI'))
+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)
+
+ 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.')
+
+ engine = engine_from_config(config.get_section(config.config_ini_section),
+ prefix='sqlalchemy.',
+ poolclass=pool.NullPool)
+
+ connection = engine.connect()
+ context.configure(connection=connection,
+ target_metadata=target_metadata,
+ process_revision_directives=process_revision_directives,
+ **current_app.extensions['migrate'].configure_args)
+
+ try:
+ with context.begin_transaction():
+ context.run_migrations()
+ finally:
+ connection.close()
+
+if context.is_offline_mode():
+ run_migrations_offline()
+else:
+ run_migrations_online()
diff --git a/migrations/script.py.mako b/migrations/script.py.mako
new file mode 100755
index 0000000..2c01563
--- /dev/null
+++ b/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"}
diff --git a/migrations/versions/780739b227a7_posts_table.py b/migrations/versions/780739b227a7_posts_table.py
new file mode 100644
index 0000000..46d334e
--- /dev/null
+++ b/migrations/versions/780739b227a7_posts_table.py
@@ -0,0 +1,37 @@
+"""posts table
+
+Revision ID: 780739b227a7
+Revises: e517276bb1c2
+Create Date: 2017-09-11 12:23:25.496587
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '780739b227a7'
+down_revision = 'e517276bb1c2'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+ # ### commands auto generated by Alembic - please adjust! ###
+ op.create_table('post',
+ sa.Column('id', sa.Integer(), nullable=False),
+ sa.Column('body', sa.String(length=140), nullable=True),
+ sa.Column('timestamp', sa.DateTime(), nullable=True),
+ sa.Column('user_id', sa.Integer(), nullable=True),
+ sa.ForeignKeyConstraint(['user_id'], ['user.id'], ),
+ sa.PrimaryKeyConstraint('id')
+ )
+ op.create_index(op.f('ix_post_timestamp'), 'post', ['timestamp'], unique=False)
+ # ### end Alembic commands ###
+
+
+def downgrade():
+ # ### commands auto generated by Alembic - please adjust! ###
+ op.drop_index(op.f('ix_post_timestamp'), table_name='post')
+ op.drop_table('post')
+ # ### end Alembic commands ###
diff --git a/migrations/versions/e517276bb1c2_users_table.py b/migrations/versions/e517276bb1c2_users_table.py
new file mode 100644
index 0000000..4353272
--- /dev/null
+++ b/migrations/versions/e517276bb1c2_users_table.py
@@ -0,0 +1,38 @@
+"""users table
+
+Revision ID: e517276bb1c2
+Revises:
+Create Date: 2017-09-11 11:23:05.566844
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'e517276bb1c2'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+ # ### commands auto generated by Alembic - please adjust! ###
+ op.create_table('user',
+ sa.Column('id', sa.Integer(), nullable=False),
+ sa.Column('username', sa.String(length=64), nullable=True),
+ sa.Column('email', sa.String(length=120), nullable=True),
+ sa.Column('password_hash', sa.String(length=128), nullable=True),
+ sa.PrimaryKeyConstraint('id')
+ )
+ op.create_index(op.f('ix_user_email'), 'user', ['email'], unique=True)
+ op.create_index(op.f('ix_user_username'), 'user', ['username'], unique=True)
+ # ### end Alembic commands ###
+
+
+def downgrade():
+ # ### commands auto generated by Alembic - please adjust! ###
+ op.drop_index(op.f('ix_user_username'), table_name='user')
+ op.drop_index(op.f('ix_user_email'), table_name='user')
+ op.drop_table('user')
+ # ### end Alembic commands ###