Resolve pillar for another Salt minion from module code

[Sébastien Santoro (Dereckson)]

Hello,

We currently use salt-tower to provide a configuration per server

for the web parts of our infrastructure (our Docker PaaS and a PHP webserver),

for the Nasqueron open-source project.

Before salt-tower, we had a pillar like this:

```

docker_containers:

  <Docker engine name>:

    <service>:

      <instance>:

```

With salt-tower, we flattened that structure and we now have directly:

```

docker_containers:

    <service>:

      <instance>:

```

The docker_containers dictionary is a merge of several .sls per service or group of services:

```

base:
- paas/docker/{{ minion_id }}/*.sls
```

Now I've a custom Salt module to select data in that docker_containers

dictionary.

A cool method get_upstreams() resolved every URL and port for Docker containers

exposing a web service in TCP, so we could something like:

proxy_pass {{ upstreams["api_foo"] }}

That method was prepared before salt-tower deployment, and can't be used

with current pillar data, as our API front-end won't see the relevant Docker pillar.

Is there a way from custom Python code (as we're at module level) to easily

trigger a pillar resolution in salt-tower for a specific node?

If something is unclear in that explanation, what we try to achieve

is available publicly here: https://devcentral.nasqueron.org/D2084

Thanks for any insights.

--

Sébastien Santoro

Nasqueron