initial add migrations support

dataserv/app.py

@@ -10,7 +10,7 @@
 sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
 
 from sqlalchemy import desc
-from dataserv.run import app, db, cache
+from dataserv.run import app, db, cache, manager
 from dataserv.Farmer import Farmer, AuthError
 from dataserv.config import logging
 
@@ -202,11 +202,11 @@ def set_height(btc_addr, height):
 
 if __name__ == '__main__':  # pragma: no cover
     # Create Database
-    db.create_all()
+    #db.create_all()
 
     # Run the Flask app
-    app.run(
-        host="0.0.0.0",
-        port=int("5000"),
-        debug=True
+    manager.run(
+    #    host="0.0.0.0",
+    #    port=int("5000"),
+    #    debug=True
     )

dataserv/migrations/README

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

dataserv/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

dataserv/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.readthedocs.org/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()

dataserv/migrations/script.py.mako

@@ -0,0 +1,22 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision}
+Create Date: ${create_date}
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

dataserv/run.py

@@ -1,6 +1,9 @@
+import os
 from flask import Flask
 from flask.ext.cache import Cache
 from flask.ext.sqlalchemy import SQLAlchemy
+from flask.ext.script import Manager
+from flask.ext.migrate import Migrate, MigrateCommand
 
 # Initialize the Flask application
 cache = Cache(config={'CACHE_TYPE': 'simple'})
@@ -9,3 +12,14 @@
 app.config.from_pyfile('config.py')
 db = SQLAlchemy(app)
 cache.init_app(app)
+
+migrate = Migrate(app, db)
+
+# didn't fix: configparser.NoSectionError: No section: 'alembic'
+#migrate = Migrate()
+#migrate.init_app(app, db, directory=os.path.join(
+#    os.path.realpath(os.path.dirname(__file__)), "migrations"
+#))
+
+manager = Manager(app)
+manager.add_command('db', MigrateCommand)

requirements.txt

@@ -3,4 +3,5 @@ Flask-SQLAlchemy == 2.0
 RandomIO == 0.2.1
 partialhash == 1.1.0
 btctxstore == 4.5.0
-Flask-Cache == 0.13.1
+Flask-Cache == 0.13.1
+Flask-Migrate == 1.5.1