Any Variables

Pete Davison

Maintainer

Task has always had variables, but even though you were able to define them using different YAML types, they would always be converted to strings by Task. This limited users to string manipulation and encouraged messy workarounds for simple problems. Starting from v3.37.0, this is no longer the case! Task now supports most variable types, including booleans, integers, floats and arrays!

What's the big deal?

These changes allow you to use variables in a much more natural way and opens up a wide variety of sprig functions that were previously useless. Take a look at some of the examples below for some inspiration.

Evaluating booleans

No more comparing strings to "true" or "false". Now you can use actual boolean values in your templates:

Before

version: 3

tasks:
  foo:
    vars:
      BOOL: true # <-- Parsed as a string even though its a YAML boolean
    cmds:
      - '{{if eq .BOOL "true"}}echo foo{{end}}'

After

version: 3

tasks:
  foo:
    vars:
      BOOL: true # <-- Parsed as a boolean
    cmds:
      - '{{if .BOOL}}echo foo{{end}}' # <-- No need to compare to "true"

Arithmetic

You can now perform basic arithmetic operations on integer and float variables:

version: 3

tasks:
  foo:
    vars:
      INT: 10
      FLOAT: 3.14159
    cmds:
      - 'echo {{add .INT .FLOAT}}'

You can use any of the following arithmetic functions: add, sub, mul, div, mod, max, min, floor, ceil, round and randInt. Check out the slim-sprig math documentation for more information.

Arrays

You can now range over arrays inside templates and use list-based functions:

version: 3

tasks:
  foo:
    vars:
      ARRAY: [1, 2, 3]
    cmds:
      - 'echo {{range .ARRAY}}{{.}}{{end}}'

You can use any of the following list-based functions: first, rest, last, initial, append, prepend, concat, reverse, uniq, without, has, compact, slice and chunk. Check out the slim-sprig lists documentation for more information.

Looping over variables using for

Previously, you would have to use a delimiter separated string to loop over an arbitrary list of items in a variable and split them by using the split subkey to specify the delimiter. However, we have now added support for looping over "collection-type" variables using the for keyword, so now you are able to loop over list variables directly:

Before

version: 3

tasks:
  foo:
    vars:
      LIST: 'foo,bar,baz'
    cmds:
      - for:
          var: LIST
          split: ','
        cmd: echo {{.ITEM}}

After

version: 3

tasks:
  foo:
    vars:
      LIST: ['foo', 'bar', 'baz']
    cmds:
      - for:
          var: LIST
        cmd: echo {{.ITEM}}

What about maps?

Maps were originally included in the Any Variables experiment. However, they weren't quite ready yet. Instead of making you wait for everything to be ready at once, we have released support for all other variable types and we will continue working on map support in the new "[Map Variables][map-variables]" experiment.

We're looking for feedback on a couple of different proposals, so please give them a go and let us know what you think. 🙏