Database Auto-configuration

For historical reasons, web applications often use environment variables to setup database and listening interface. That abstracts provisioning systems from getting into details of each application configuration.

So called “dotenv” - .env files in root of deployment have been used to store such environment variables.

Therefore, FutoIn database concept provides a handy AutoConfig utility. It is possible to supply supported database type as “type” option of preconfigured connection. Example:

const DBAutoConfig = require('futoin-database/AutoConfig');
DBAutoConfig(as, ccm, {
    // DB_MAIN_TYPE must be either of these
    main : { type: ['mysql', 'postgresql'] },
    // DB_DWH_TYPE must be exactly this
    dwh : { type: 'postgresql' },
});
as.add( (as) => {
    // Use connection called "main"
    ccm.db('main').query(as, '...');
    // the same
    ccm.iface('#db.main').query(as, '...');
    // use another connection
    ccm.db('dwh').query(as, '...');
});

For each named database, a dedicated interface is registered on CCM with special #db.${name} alias.

Environment variable pattern

Note: {NAME} is connection name in uppercase

• DB_{NAME}_TYPE - type of database engine.
• DB_{NAME}_HOST - target host.
• DB_{NAME}_PORT - target TCP, UDP or UNIX port.
• DB_{NAME}_USER - user name.
• DB_{NAME}_PASS - user password.
• DB_{NAME}_DB - database name.
• DB_{NAME}_MAXCONN - maximum concurrent connections allowed.

DB_TYPE, DB_HOST, DB_PORT, DB_USER, DB_PASS, DB_DB and DB_MAXCONN environment variables are used to autoconfigure “default” connection.

DB_{NAME}_TYPE, DB_{NAME}_HOST, DB_{NAME}_PORT and other variable names are used to configure any arbitrary ”{name}” connection. The list of expected connection names must be supplied to AutoConfig() function.

CCM extension

AutoConfig adds a handy ccm.db(name) API extension to particular CCM instance. This is shortcut for calling ccm.iface('#db.${name}').