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Extend barnard59 CLI

To create additional CLI commands for the barnard59 CLI you will need to first create and publish a package whose name starts with barnard59-. If you have not, follow the tutorial. The rest of this how-to will use that barnard59-time-zone as the example.

When you complete this how-to, you will be able to run a new barnard59 time-zone fetch command.

Create manifest entry​

If necessary, create and open a manifest.ttl in the package root. In it, add the following triples:

@base <https://barnard59.zazuko.com/> .
@prefix b59: <https://barnard59.zazuko.com/vocab#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

<command/time-zone/fetch>
    a b59:CliCommand ;
    b59:command "fetch" ;
    rdfs:label "Gets current time in the specific time zone" ;
    b59:source "barnard59-time-zone/pipeline/main.ttl" ;
.

The b59:CliCommand type, and b59:command and b59:source properties are required.

b59:source must be a node identifier matching the package name and path.

The identifier of the CLI Command resource is not that important, but it should be guaranteed to be unique and basing it in the https://barnard59.zazuko.com/command is current best practice which may be used in the future for dereferencing manifest descriptions.

Label is optional.

Selecting pipeline identifier​

In case when the pipeline definition contains sub-pipelines, the manifest will need to also include the exact identifier, similarly how the --pipeline CLI flag is required.

@prefix b59: <https://barnard59.zazuko.com/vocab#> .

<command/time-zone/fetch>
    b59:pipeline <http://example.org/pipeline/tz> ;
.

Mapping variables to CLI options​

Root pipeline variables will be mapped to CLI options. All options are required unless they have p:required false or p:value

The pipeline http://example.org/pipeline/tz has one variable:

pipeline/main.ttl
<tz> a p:Pipeline, p:Readable ;
  p:variables
    [
      p:variable
        [
          a p:Variable ;
          p:name "TZ" ;
          p:value "UTC" ;
        ]
    ] ;
  p:steps
    [

It will be mapped to an optional CLI option:

barnard59 time-zone fetch --TZ Europe/Amsterdam