Add Alembic health checks that validates the DB is at the last version

.gitignore

@@ -1,3 +1,5 @@
+__pycache__
+*.pyc
 /.venv/
 /acceptance_tests/app/c2cwsgiutils
 /acceptance_tests/app/c2cwsgiutils_coverage_report.py
@@ -13,5 +15,5 @@
 /c2cwsgiutils.egg-info/
 /dist/
 /reports/
-.idea/dbnavigator.xml
-.idea/inspectionProfiles
+/.idea/dbnavigator.xml
+/.idea/inspectionProfiles

README.md

@@ -182,15 +182,17 @@ health_check = HealthCheck(config)
 health_check.add_db_session_check(models.DBSession, at_least_one_model=models.Hello)
 health_check.add_url_check('http://localhost/api/hello')
 health_check.add_custom_check('custom', custom_check, 2)
+health_check.add_alembic_check(models.DBSession, '/app/alembic.ini', 3)
 ```
 
-Then, the URL `{C2C_BASE_PATH}/health_check?max_level=2` can be used to run the health checks and get a report
+Then, the URL `{C2C_BASE_PATH}/health_check?max_level=3` can be used to run the health checks and get a report
 looking like that (in case of error):
 
 ```json
 {
     "status": 500,
-    "successes": ["db_engine_sqlalchemy", "db_engine_sqlalchemy_slave", "http://localhost/api/hello"],
+    "successes": ["db_engine_sqlalchemy", "db_engine_sqlalchemy_slave", "http://localhost/api/hello", 
+                  "alembic_app_alembic.ini"],
     "failures": {
         "custom": {
             "message": "I'm not happy"
@@ -199,6 +201,8 @@ looking like that (in case of error):
 }
 ```
 
+Look at the documentation of the `c2cwsgiutils.health_check.HealthCheck` class for more information.
+
 
 SQLAlchemy models graph
 -----------------------

acceptance_tests/app/alembic.ini

@@ -0,0 +1,32 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = app_alembic
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# max length of characters to apply to the
+# "slug" field
+#truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; this defaults
+# to alembic/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path
+# version_locations = %(here)s/bar %(here)s/bat alembic/versions
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+sqlalchemy.url = %(SQLALCHEMY_URL)s

acceptance_tests/app/app_alembic/env.py

@@ -0,0 +1,76 @@
+from __future__ import with_statement
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from logging.config import fileConfig
+import os
+
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+config.set_main_option('sqlalchemy.url', os.environ["SQLALCHEMY_URL"])
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig('production.ini', defaults=os.environ)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+target_metadata = None
+
+# 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.
+
+    """
+    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,
+            # To allow to run "UPDATE" in a migration and do an "ALTER" in another one, later.
+            transaction_per_migration=True
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

acceptance_tests/app/app_alembic/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"}

acceptance_tests/app/app_alembic/versions/4a8c1bb4e775_initial_version.py

@@ -0,0 +1,30 @@
+"""Initial version
+
+Revision ID: 4a8c1bb4e775
+Revises:
+Create Date: 2016-09-14 09:23:27.466418
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '4a8c1bb4e775'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.execute("CREATE EXTENSION IF NOT EXISTS postgis;")
+    op.execute("""
+    CREATE TABLE hello (
+      id SERIAL PRIMARY KEY,
+      value TEXT UNIQUE INITIALLY DEFERRED
+    )
+    """)
+
+
+def downgrade():
+    pass

acceptance_tests/app/c2cwsgiutils_app/__init__.py

@@ -22,5 +22,6 @@ def main(_, **settings):
     health_check.add_db_session_check(models.DBSession, at_least_one_model=models.Hello)
     health_check.add_url_check('http://localhost/api/hello')
     health_check.add_custom_check('fail', _failure, 2)
+    health_check.add_alembic_check(models.DBSession, '/app/alembic.ini', 1)
 
     return config.make_wsgi_app()

acceptance_tests/app/requirements.txt

@@ -1,2 +1,3 @@
 -r rel_requirements.txt
+alembic==0.9.2
 flake8==3.3.0

acceptance_tests/app/run_alembic.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# Upgrade the DB
+set -e
+
+# wait for the DB to be UP
+while ! echo "import sqlalchemy; sqlalchemy.create_engine('$SQLALCHEMY_URL').connect()" | python 2> /dev/null
+do
+    echo "Waiting for the DB to be reachable"
+    sleep 1;
+done
+
+for ini in *alembic*.ini
+do
+    if [[ -f $ini ]]
+    then
+        echo "$ini ==========================="
+        alembic -c $ini upgrade head
+    fi
+done

acceptance_tests/tests/docker-compose.yml

@@ -10,7 +10,7 @@ app:
     SQL_PROFILER_SECRET: changeme
     DEBUG_VIEW_SECRET: changeme
     LOG_HOST: 172.17.0.1
-    LOG_TYPE: 'json,logstash'
+    LOG_TYPE: 'console,logstash'
     SQL_LOG_LEVEL: DEBUG
     OTHER_LOG_LEVEL: DEBUG
     DEVELOPMENT: 1
@@ -21,6 +21,22 @@ app:
   ports:
     - 8480:80
 
+alembic_master:
+  image: camptocamp/c2cwsgiutils_test_app:${DOCKER_TAG}
+  environment:
+    SQLALCHEMY_URL: postgresql://www-data:www-data@db:5432/test
+  links:
+    - db
+  command: /bin/true  # will use execute with another script from the tests to actually do it
+
+alembic_slave:
+  image: camptocamp/c2cwsgiutils_test_app:${DOCKER_TAG}
+  environment:
+    SQLALCHEMY_URL: postgresql://www-data:www-data@db:5432/test
+  links:
+    - db_slave:db
+  command: /bin/true  # will use execute with another script from the tests to actually do it
+
 db:
   image: camptocamp/postgresql:pg9.5-latest
   environment:

acceptance_tests/tests/tests/conftest.py

@@ -32,25 +32,20 @@ def app_connection(composition):
 
 @pytest.fixture(scope="session")
 def master_db_setup(composition):
-    return _create_table(master=True)
+    return _create_table(composition, master=True)
 
 
 @pytest.fixture(scope="session")
 def slave_db_setup(composition):
-    return _create_table(master=False)
+    return _create_table(composition, master=False)
 
 
-def _create_table(master):
+def _create_table(composition, master):
     name = 'master' if master else 'slave'
+    composition.run('alembic_' + name, '/app/run_alembic.sh')
     connection = _connect(master)
     with connection.cursor() as curs:
-        LOG.info("Creating table for " + name)
-        curs.execute("""
-        CREATE TABLE hello (
-          id SERIAL PRIMARY KEY,
-          value TEXT UNIQUE INITIALLY DEFERRED
-        )
-        """)
+        LOG.info("Creating data for " + name)
         curs.execute("INSERT INTO hello (value) VALUES ('%s')" % (name))
     connection.commit()
     return connection

acceptance_tests/tests/tests/test_health_check.py

@@ -6,7 +6,8 @@ def test_ok(app_connection):
     print('response=' + json.dumps(response))
     assert response == {
         'status': 200,
-        'successes': ['db_engine_sqlalchemy', 'db_engine_sqlalchemy_slave', 'http://localhost/api/hello'],
+        'successes': ['db_engine_sqlalchemy', 'db_engine_sqlalchemy_slave', 'http://localhost/api/hello',
+                      'alembic_app_alembic.ini'],
         'failures': {}
     }
 
@@ -16,7 +17,8 @@ def test_failure(app_connection):
     print('response=' + json.dumps(response))
     assert response == {
         'status': 500,
-        'successes': ['db_engine_sqlalchemy', 'db_engine_sqlalchemy_slave', 'http://localhost/api/hello'],
+        'successes': ['db_engine_sqlalchemy', 'db_engine_sqlalchemy_slave', 'http://localhost/api/hello',
+                      'alembic_app_alembic.ini'],
         'failures': {
             'fail': {
                 'message': 'failing check',

c2cwsgiutils/db.py

@@ -27,9 +27,9 @@ def setup_session(config, master_prefix, slave_prefix=None, force_master=None, f
     path includes the route_prefix.
 
     :param config: The pyramid Configuration object
-    :param master_prefix: The prefix for the master connection configuration entries in the application
+    :param master_prefix: The prefix for the master connection configuration entries in the application \
                           settings
-    :param slave_prefix: The prefix for the slave connection configuration entries in the application
+    :param slave_prefix: The prefix for the slave connection configuration entries in the application \
                          settings
     :param force_master: The method/paths that needs to use the master
     :param force_slave: The method/paths that needs to use the slave