Setting connection runtime options

[moll]

Hey,

I need to SET a few PostgreSQL options right after connecting. Where have you envisioned such settings to take place?

I see getRawConnection in postgres.js is reponsible for creating a new connection — that could be a place for a temporary injection, but what are your thoughts for long term?

[tgriesser]

Just to make sure I'm understanding the question - these are options that need to be set just after connection on each individual connection in the pool (before the connection is added to the pool) correct?

[moll]

Yep, that's the way PostgreSQL runtime opts work: http://www.postgresql.org/docs/9.2/static/sql-set.html

[tgriesser]

@moll - I added an option to specify a beforeCreate afterCreate function on the pool options during initialize, which accepts the connection that's being added to the pool, and a done function that should be called after any setup you need to do is complete.

Knex.Initialize({
  client: 'pg',
  connection: {...},
  pool: {
    afterCreate: function(conn, done) {
      conn.query('SET ....', function() {
         done();
      });
    }
  }
});

Since this is the actual connection - you'll need to use it like you would in the pg module.

Let me know if this works alright, or if there's anything that could be improved here.

[moll]

Nice work.

Though, one thing, I think the naming for beforeCreate is a tad misleading — afterCreate would be more appropriate given it's actually called after creating the connection. Or if you were going for the "before adding to the pool" semantic, then beforeCreate doesn't fit either. But afterCreate would sound decent.

[moll]

Oh and why not pass the error given to the callback by before/afterCreate up the stack? Though maybe that would require tearing down the connection before passing the error on.

[tgriesser]

Yeah, afterCreate sounds better... I was going for the "before adding to the pool"... but as you pointed out that doesn't quite fit.

I'm going to take a closer look at cleaning up the pool error handling in general, related to #4... but are you thinking that it should be something along the lines of:

conn.query('SET ....', function(err, resp) {
   done(err);
});

[moll]

If you agree with afterCreate, do a quick rename before anyone starts using 0.1.5. ;)

[moll]

By passing the error on, I meant instead of:

        this.beforeCreate(conn, function() {
          callback(null, conn);
        });

do

        this.beforeCreate(conn, function(err) {
          callback(err, conn);
        });

[tgriesser]

@moll - 0.1.6 is out... with both of the changes you suggested :)

[moll]

Superb.