Make sure that the default settings signal that no email server is configured (#4226)

* The sender email address has to be None for the test of "is email server
configured" to be correct. Moved the dev setting into docker-compose.yml.

* Move the REDASH_MAIL_SERVER setting into docker-compose.yml to revert the default value to its original value in case anyone was using it.

* Make worker dependant on email as it's the one that actually using it.

docker-compose.yml

@@ -8,7 +8,6 @@ services:
     depends_on:
       - postgres
       - redis
-      - email
     ports:
       - "5000:5000"
       - "5678:5678"
@@ -20,6 +19,8 @@ services:
       REDASH_REDIS_URL: "redis://redis:6379/0"
       REDASH_DATABASE_URL: "postgresql://postgres@postgres/postgres"
       REDASH_RATELIMIT_ENABLED: "false"
+      REDASH_MAIL_DEFAULT_SENDER: redash@example.com
+      REDASH_MAIL_SERVER: email
   worker:
     build: .
     command: dev_worker
@@ -29,6 +30,7 @@ services:
         target: /app
     depends_on:
       - server
+      - email
     environment:
       PYTHONUNBUFFERED: 0
       REDASH_LOG_LEVEL: "INFO"
@@ -36,6 +38,8 @@ services:
       REDASH_DATABASE_URL: "postgresql://postgres@postgres/postgres"
       QUEUES: "queries,scheduled_queries,celery,schemas"
       WORKERS_COUNT: 2
+      REDASH_MAIL_DEFAULT_SENDER: redash@example.com
+      REDASH_MAIL_SERVER: email
   redis:
     image: redis:3-alpine
     restart: unless-stopped

redash/settings/__init__.py

@@ -210,13 +210,13 @@ CELERYD_WORKER_TASK_LOG_FORMAT = os.environ.get(
                     'task_id=%(task_id)s %(message)s')))
 
 # Mail settings:
-MAIL_SERVER = os.environ.get('REDASH_MAIL_SERVER', 'email')
+MAIL_SERVER = os.environ.get('REDASH_MAIL_SERVER', 'localhost')
 MAIL_PORT = int(os.environ.get('REDASH_MAIL_PORT', 25))
 MAIL_USE_TLS = parse_boolean(os.environ.get('REDASH_MAIL_USE_TLS', 'false'))
 MAIL_USE_SSL = parse_boolean(os.environ.get('REDASH_MAIL_USE_SSL', 'false'))
 MAIL_USERNAME = os.environ.get('REDASH_MAIL_USERNAME', None)
 MAIL_PASSWORD = os.environ.get('REDASH_MAIL_PASSWORD', None)
-MAIL_DEFAULT_SENDER = os.environ.get('REDASH_MAIL_DEFAULT_SENDER', 'john@example.com')
+MAIL_DEFAULT_SENDER = os.environ.get('REDASH_MAIL_DEFAULT_SENDER', None)
 MAIL_MAX_EMAILS = os.environ.get('REDASH_MAIL_MAX_EMAILS', None)
 MAIL_ASCII_ATTACHMENTS = parse_boolean(os.environ.get('REDASH_MAIL_ASCII_ATTACHMENTS', 'false'))