Allow configuration options for Postgres

[kulshekhar]

The current implementation of the Postgres adapter establishes a connection using the default settings. It would be helpful if we could customize the options available in the Postgres driver. As things stand, there are two sets of options that can be configured:

• The initialization options for the pg-promise wrapper
• The options for the node-postgres instance available via pgp.pg.defaults.OPTION_NAME

To implement this, parse server can accept them individually as command line parameters/environment variable (the existing --databaseOptions option and a new option).

Alternatively, they can be combined into the existing --databaseOptions option with the convention that this option have a structure similar to:

{
  "pgpOptions": { },
  "pgOptions": { }
}

Of course, the keys could have more descriptive names. If we can decide on the preferable approach and the naming convention, I could take a stab at implementing this.

[flovilmart]

we have similar options for the mongodb adapter, I'll let you knock a first implementation.
I'd put both options hashes in the same databaseOptions wrapped for the sake of simplicity. What do you think?

[kulshekhar]

Yeah, that would be my preferred way of implementing it as well. I'll get started with this then

[flovilmart]

@kulshekhar awesome that you're picking that up! Did you get a chance to test the adapter with a simple configuration?

[kulshekhar]

I was able to create a class and fields using parse dashboard, if that's what you mean. I haven't done much else so far.

I used something like this to start parse server:

parse-server --appId a --masterKey m --databaseURI postgres://username:password@localhost:5432/parse-db

[flovilmart]

Awesome!

[kulshekhar]

It seems that the following format for the options would be more user-friendly:

{
  "host": "",
  "port": "",
  "...": "",
  "pgOptions": {}
}

This would have all the options offered by pg-promise at the first level. All the options offered by node-postgres could be under the pgOptions hash.

This is how I'm currently implementing it. Let me know if you want me to change this.

[flovilmart]

That looks good :)

[rendongsc]

@flovilmart
databaseOptions can by PostgresConfigParser.getDatabaseOptionsFromURI.
replace ParseServer config databaseOptions for pg initialization options.

var api = new ParseServer({
  databaseURI: databaseUri || 'postgres://Test:123@localhost:5432/Test',
  cloud: process.env.CLOUD_CODE_MAIN || __dirname + '/cloud/main.js',
  appId: process.env.APP_ID || 'myAppId',
  masterKey: process.env.MASTER_KEY || '', //Add your master key here. Keep it secret!
  serverURL: process.env.SERVER_URL || 'http://localhost:1337/parse',  
  liveQuery: {
    classNames: ["Posts", "Comments"] // List of classes to support for query subscriptions
  },
  databaseOptions: {
    connect: function (client, dc, isFresh) {      
      if (isFresh) {       
        client.query('SET search_path = cust');
      }
    }
  }
});

PostgresClient.js

const parser = require('./PostgresConfigParser');

export function createClient(uri, databaseOptions) {
  let dbOptions = {};
  databaseOptions = databaseOptions || {};

  if (uri) {
    dbOptions = parser.getDatabaseOptionsFromURI(uri);
  }

  let pgp = require('pg-promise')(databaseOptions);

  const client = pgp(dbOptions);

  if (dbOptions.pgOptions) {
    for (const key in dbOptions.pgOptions) {
      client.pg.defaults[key] = dbOptions.pgOptions[key];
    }
  }

  return client;
}

[flovilmart]

@rendongsc I'm not sure what you mean. Is that an issue for you?

[rendongsc]

yes, it's about the use of databaseOptions