Support env variables for options

[zZHorizonZz]

Describe the feature

It would be handy if the default options like worker, instances etc could be made to be also passable trough env variables i.e VERTX_WORKER, VERTX_INSTANCES and such.

Contribution

No response

[tsegismont]

That sounds good, would you volunteer for it?

If we do this, what about the order of precedence? There are priorities defined in vertx-pg-client and vertx-config. Are they the same?

[zZHorizonZz]

I don't mind. Though thinking about it more wouldn't it be better to use vertx-config? Which would would make things easier to implement trough one unified system and would allow for system properties for example as well?

[tsegismont]

We had that debate long time ago and the outcome was to not force users to have a mandatory dependency on Vert.x Config.

What's important to me today is that we get a consistent order of precedence, if possible.

[zZHorizonZz]

We had that debate long time ago and the outcome was to not force users to have a mandatory dependency on Vert.x Config.

Right.

What's important to me today is that we get a consistent order of precedence, if possible.

Well I'm not really sure what is the order in vertx-pg-client but as for vertx-config shouldn't it be last come last serve order or is there some internal priority I'm not aware of?

[zZHorizonZz]

But I think that arguments should take precedence over env variables. This is also what nodejs does https://nodejs.org/api/cli.html#options

Options from the command line take precedence over options passed through the NODE_OPTIONS environment variable.

[tsegismont]

I think that arguments should take precedence over env variables.

Sounds good to me