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Map Variables (#1585)

caution

All experimental features are subject to breaking changes and/or removal at any time. We strongly recommend that you do not use these features in a production environment. They are intended for testing and feedback only.

Currently, Task supports all variable types except for maps. This experiment adds two different proposals for map variables. Click on the tabs below to switch between them.

warning

This experiment proposal breaks the following functionality:

  • Dynamically defined variables (using the sh keyword)
info

To enable this experiment, set the environment variable: TASK_X_MAP_VARIABLES=1. Check out our guide to enabling experiments for more information.

This proposal removes support for the sh keyword in favour of a new syntax for dynamically defined variables, This allows you to define a map directly as you would for any other type:

version: 3

tasks:
foo:
vars:
FOO: {a: 1, b: 2, c: 3} # <-- Directly defined map on the `FOO` key
cmds:
- 'echo {{.FOO.a}}'

Migration

Taskfiles with dynamically defined variables via the sh subkey will no longer work with this experiment enabled. In order to keep using dynamically defined variables, you will need to migrate your Taskfile to use the new syntax.

Previously, you might have defined a dynamic variable like this:

version: 3

tasks:
foo:
vars:
CALCULATED_VAR:
sh: 'echo hello'
cmds:
- 'echo {{.CALCULATED_VAR}}'

With this experiment enabled, you will need to remove the sh subkey and define your command as a string that begins with a $. This will instruct Task to interpret the string as a command instead of a literal value and the variable will be populated with the output of the command. For example:

version: 3

tasks:
foo:
vars:
CALCULATED_VAR: '$echo hello'
cmds:
- 'echo {{.CALCULATED_VAR}}'

If your current Taskfile contains a string variable that begins with a $, you will now need to escape the $ with a backslash (\) to stop Task from executing it as a command.

Looping over maps

This experiment also adds support for looping over maps using the for keyword, just like arrays. In addition to the {{.ITEM}} variable being populated when looping over a map, we also make an additional {{.KEY}} variable available that holds the string value of the map key.

version: 3

tasks:
foo:
vars:
MAP: {a: 1, b: 2, c: 3}
cmds:
- for:
var: MAP
cmd: 'echo "{{.KEY}}: {{.ITEM}}"'