Merge pull request #102 from xsnippet/alembic

Use alembic for schema migrations

.github/workflows/tests.yml

@@ -65,13 +65,46 @@ jobs:
           toolchain: ${{ matrix.rust-version }}
           override: true
 
-      - name: Install libpq (Windows)
-        if: matrix.os == 'windows-latest'
+      - name: Start PostgreSQL and create a database  (Linux)
+        if: runner.os == 'Linux'
+        run: |
+          sudo service postgresql start
+          sudo -u postgres createuser -s devel
+          sudo -u postgres createdb -O devel devel
+          sudo -u postgres psql -c "ALTER USER devel PASSWORD 'devel';" devel
+          echo '::set-env name=DATABASE_URL::postgres://devel:devel@localhost/devel'
+
+      - name: Start PostgreSQL and create a database (MacOS)
+        if: runner.os == 'macOS'
+        run: |
+          /usr/local/opt/postgres/bin/pg_ctl -D /usr/local/var/postgres start
+          /usr/local/opt/postgres/bin/createuser -s devel
+          /usr/local/opt/postgres/bin/createdb -O devel devel
+          /usr/local/opt/postgres/bin/psql -c "ALTER USER devel PASSWORD 'devel';" devel
+          echo '::set-env name=DATABASE_URL::postgres://devel:devel@localhost/devel'
+
+      - name: Start PostgreSQL and create a database (Windows)
+        if: runner.os == 'Windows'
         shell: bash
         run: |
-          choco install postgresql12 --force --params '/Password:root'
           echo '::add-path::C:\Program Files\PostgreSQL\12\bin'
           echo '::add-path::C:\Program Files\PostgreSQL\12\lib'
+          echo '::set-env name=PQ_LIB_DIR::C:\Program Files\PostgreSQL\12\lib'
+          sc config postgresql-x64-12 start= demand
+          net start postgresql-x64-12
+          "C:\Program Files\PostgreSQL\12\bin\createuser" -s devel
+          "C:\Program Files\PostgreSQL\12\bin\createdb" -O devel devel
+          "C:\Program Files\PostgreSQL\12\bin\psql" -c "ALTER USER devel PASSWORD 'devel';" devel
+          echo '::set-env name=DATABASE_URL::postgres://devel:devel@localhost/devel'
+
+      - name: Install Alembic and psycopg2
+        run: |
+          python -m pip install --upgrade wheel
+          python -m pip install --upgrade alembic psycopg2
+
+      - name: Run database migrations
+        run: |
+          python -m alembic.config upgrade head
 
       - uses: actions-rs/cargo@v1
         with:

.gitignore

@@ -1 +1,2 @@
 /target
+__pycache__

alembic.ini

@@ -0,0 +1,36 @@
+[alembic]
+script_location = src/storage/sql/migrations/
+
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = INFO
+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

src/storage/sql/migrations/env.py

@@ -0,0 +1,53 @@
+import logging.config
+import os
+
+from alembic import context
+from sqlalchemy import create_engine, pool
+
+
+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.
+
+    """
+
+    context.configure(
+        url=os.environ['DATABASE_URL'],
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    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.
+
+    """
+
+    connectable = create_engine(
+        os.environ['DATABASE_URL'],
+        poolclass=pool.NullPool,
+    )
+    with connectable.connect() as connection:
+        context.configure(connection=connection)
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+logging.config.fileConfig(context.config.config_file_name)
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

src/storage/sql/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"}

src/storage/sql/migrations/versions/1bf4e4e7b24f_initial_schema.py

@@ -0,0 +1,107 @@
+"""Initial schema
+
+Revision ID: 1bf4e4e7b24f
+Revises:
+Create Date: 2020-07-26 08:46:28.752972
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = '1bf4e4e7b24f'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    metadata = sa.MetaData()
+
+    sa.Table(
+        'snippets', metadata,
+
+        # an internal autoincrementing identifier; only used in foreign keys
+        sa.Column('id', sa.Integer, primary_key=True),
+        # a short unique snippet identifier visible to users
+        sa.Column('slug', sa.String(32), nullable=False),
+
+        sa.Column('title', sa.Text),
+        sa.Column('syntax', sa.Text),
+        sa.Column('created_at', sa.DateTime(timezone=True),
+                  server_default=sa.func.now(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True),
+                  server_default=sa.func.now(), nullable=False),
+
+        # slugs must be unique (this will also automatically create a unique index)
+        sa.UniqueConstraint('slug', name='uq_slug'),
+
+        # will be used for pagination; slug guarantees uniqueness of the sorting key
+        sa.Index('snippets_created_at_slug', 'created_at', 'slug'),
+        sa.Index('snippets_updated_at_slug', 'updated_at', 'slug'),
+    )
+
+    sa.Table(
+        'changesets', metadata,
+
+        # an internal autoincrementing identifier; only used in foreign keys
+        sa.Column('id', sa.Integer, primary_key=True),
+        sa.Column('snippet_id', sa.Integer, nullable=False),
+
+        # numeric index used to determine the ordering of changesets for a given snippet
+        sa.Column('version', sa.Integer,
+                  server_default=sa.text('0'), nullable=False),
+        sa.Column('content', sa.Text, nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True),
+                  server_default=sa.func.now(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True),
+                  server_default=sa.func.now(), nullable=False),
+
+        # there can be multiple changesets per snippet; changesets should be
+        # deleted when the parent snippet is deleted
+        sa.ForeignKeyConstraint(['snippet_id'], ['snippets.id'],
+                                ondelete='CASCADE', name='fk_snippet',
+                                use_alter=False),
+        # each changeset is supposed to have a unique version number
+        sa.UniqueConstraint('snippet_id', 'version',
+                            name='uq_version'),
+        # sanity check: do not allow empty changesets
+        sa.CheckConstraint('LENGTH(content) > 0',
+                           name='check_not_empty'),
+        # sanity check: version numbers are non-negative integers
+        sa.CheckConstraint('version >= 0',
+                           name='check_non_negative_version')
+
+    )
+
+    # tags could have been associated with snippets as M:M via an auxiliary table,
+    # but Diesel only supports child-parent associations, so let's do that instead
+    sa.Table(
+        'tags', metadata,
+
+        # an internal autoincrementing identifier; only used in foreign keys
+        sa.Column('id', sa.Integer, primary_key=True),
+        sa.Column('snippet_id', sa.Integer, nullable=False),
+
+        sa.Column('value', sa.Text, nullable=False),
+
+        # there can be multiple tags per snippet; tags should be deleted when
+        # the parent snippet is deleted
+        sa.ForeignKeyConstraint(['snippet_id'], ['snippets.id'],
+                                ondelete='CASCADE',
+                                name='fk_snippet'),
+
+        # do not allow to abuse the tags for storing too much data
+        sa.CheckConstraint('LENGTH(value) < 128', name='check_length'),
+        # do not allow repeated tags per snippet
+        sa.UniqueConstraint('snippet_id', 'value', name='uq_snippet_tag'),
+    )
+
+    metadata.create_all(op.get_bind())
+
+
+def downgrade():
+    op.drop_table('tags')
+    op.drop_table('changesets')
+    op.drop_table('snippets')