Re: code review

[Catonano]

2017-09-12 21:35 GMT+02:00 Christopher Baines <address@hidden>:

On Mon, 11 Sep 2017 22:10:22 +0200
Catonano <address@hidden> wrote:

> I could use some code review on my Trytond service hypothesis
>
> As far as I understand, there are 2 steps that need to be done in
> order for a Trytond service to be usable.
>
> 1) as the "postgres" role (that is as the operating system "postgres"
> user), create a "tryton" role
>
> 2) as the tryton user (hence under the tryton role) run the Tryton
> initialization script (trytond-admin -c <config file> -d <database
> name> --all)
>
> I feel like I should extend the postgresql service in order to create
> te trytond role but I don't know how

I don't think there is any current approach for doing this.

Service extension could be one way of doing it. It's similar to how
other services in Guix interact with each other.

However, I believe creating a role can only be done when the PostgreSQL
server is running, which means that you'd need to defer creating the
role until that point. Keeping this in a single shepherd service might
not be easy to implement, and even if you did, there are some usability
issues, e.g. if you add a new service to the system, and that service
also extends PostgreSQL, then you might run in to trouble creating the
role for the new service, without needlessly restarting the PostgreSQL
service in the process.

One approach I've implemented and used [1] is to do create roles for
PostgreSQL when you start the service that uses that role.

Yes, I'll work on this approach from now on
 

I also remember Ludo suggesting using additional services to handle
this kind of setup, which I understood to be something like a
tryton-postgresql-role shepherd service, which the tryton shepherd
service would require.

I attempted this but my trytond-postgres-role-service-type doesn't extend shepherd-root-service-type

I chose not to extend shepherd-root-service-type because the trytond role doesn't require a daemon running

It has to be created one off (una tantum) so, I tought, a simple activation will do

But now, the trytond-service-type (in charge of running the trytond daemon) should require trytond-postgres-role among its dependencies but there is NO sheperd service provisioning a postgres role

So this is what I end up with (when testing the system with the marionette machinery)

srfi/srfi-1.scm:640:9: In procedure for-each:
srfi/srfi-1.scm:640:9: Throw to key `srfi-34' with args `(#<condition &message [message: "service 'trytond' requires 'trytond-postgres-role', which is not provided by any service"] 44bd120>)'.
make: *** [Makefile:5295: check-system] Error 1

Should I make the trytond-postgres-role a sheperd service ?

Admittedly I don't like the idea

So, I'm thinking, I'll get back to creating the postgres role upon activation of the trytond-service-type

I failed to foresee this issue so I wasted some work :-/

The branch is here, should anyone want to take a look (pay attention, I rebase carelessly)
https://gitlab.com/humanitiesNerd/guix-hacks