External variables

CLI commands working with a descriptor accept the -p, --param, which specifies the YAML to use as a source for external variables. Those variables can then be used in templating. Templating is always applied to descriptors and can be optionally applied to arbitrary files in components.

Variables

Variables can come from:

  • An external source like the file described here,
  • A vars section in that can be specified in each descriptor file.

File format

The only requirement is that the file must be a valid YAML file. Data can be structured as required.

Consider this trivial example:

app:
  visualizer:
    port: 8080

And this descriptor:

name: myEnv
providers:
  ek-aws:
    params:
      securityGroups:
        app:
          rules:
            - proto: tcp
              ports:
                - {{ .Vars.app.visualizer.port }} 
              cidr_ip: 0.0.0.0/0
              rule_desc: allow all on port {{ .Vars.app.visualizer.port }} for the swarm visualizer 

# ...

The following effective descriptor will be produced:

Will produce :

name: myEnv
providers:
  ek-aws:
    params:
      securityGroups:
        app:
          rules:
            - proto: tcp
              ports:
                - 8080
              cidr_ip: 0.0.0.0/0
              rule_desc: allow all on port 8080 for the swarm visualizer 

# ...