The production instance of DBaaS application uses Nginx for web proxy. The Nginx web proxy is deployed as a separate Docker container. Nginx listens on ports 80 and 443. Nginx proxies web requests to dbaas via uWSGI on port 5000. Nginx maintains the SSL certificates. uWSGI is installed in the same container as the DBaas flask application. The link between Nginx and uWSGI is defined in the file: <docker-compose.yml>. The dbaas Flask application listens on port 5000 using the uWSGI protocol.
Switching to development on VM's. For development I use a different AWS bucket for testing backups.
export DB4SCI_MODE=prod
# OR
export DB4SCI_MODE=devThe SSL certs can be different between production and development. Place production certs in prod/nginx/ssl and development certs in dev/nginx/ssl directories. Production and developemnt domains are seperated by folder name for nginx.
All differences between produciton and development for DBaas are contained in the config.py file.vProd and Dev are defined as classes in the config file.
The need to support multible different versions of database containers is supported. Docker images used by the application are defined in mydb/config.py. Database containers are configured by mapping config files to the container. Additional mappings are defined in the config.py for each DB type. Config files can be stored in the /dbconfig directory with subdirectories for each database type.
file: mydb/config.py
# images: List of Docker Images
# first column is 'Display Name'
# second column is 'image name'
# firt row of image is default
info = {'Postgres': {'pub_ports': [5432],
'backupdir': '/var/lib/postgresql/backup',
'volumes': [
['DBVOL', '/', '/var/lib/postgresql/data'],
[backupvol, '/', '/var/lib/postgresql/backup'],
],
'command': 'postgres',
'dbengine': 'Postgres',
'images': [
['Postgres 9.6.10', 'postgres:9.6.10'],
['Postgres 10.5', 'postgres:10.5'],
]},DB4SCI maintains application status in its own Postgres Database (mydb_admin). All actions to database continers are logged in the database; create container, restart, delete, backup. The admin_database has four tables: Container, State, Log and Backup_log. The state table contains the names of running containers and is used for backup and recovery. DB4Sci will create the mydb_admin container if it is not running, typically this is done once the first time the application is started. Full backups are made of mydb_admin. mydb_admin is a critical part of the application, should it be harmmed the database should be recovered.
Robert McDermott created the initial application in one weekend during the spring of 2016. The initial application was called 'postgres_container_mgmt'. Mija Lee supported all the the early Postgres support and coding for creating, configuring and backups for Postgres. John Dey is the current maintainer.
The primary Flask daemon is called dbaas (Data Base as a service). The applacation was renamed from postgres_contianer_mgmt to mydb. This name change reflected the general use case of creating any type of database container, not just PostgreSQL. Support for Maria, Mongo and Neo4j were added based on user requests. It was always the intent to make MyDB a public repository but the name MyDB was not available. The second name change to DB4Sci was result of making the code public. DB4Sci logo was created by the publication department at the Fred Hutch.
The name mydb is used throughout the code, mydb is short and easy to type and will remain within the code. The name DB4Sci will be used when refering to the application.