Task - Simple "Make" alternative

Task is a simple tool that allows you to easily run development and build tasks. Task is written in Go, but can be used to develop any language. It aims to be simpler and easier to use then GNU Make.

Installation

If you have a Go environment setup, you can simply run:

go get -u -v github.com/go-task/task/cmd/task

Or you can download from the releases page and add to your PATH.

Usage

Create a file called Taskfile.yml in the root of the project. (Taskfile.toml and Taskfile.json are also supported, but YAML is used in the documentation). The cmds attribute should contains the commands of a task:

build:
  cmds:
    - go build -v -i main.go

assets:
  cmds:
    - gulp

Running the tasks is as simple as running:

task assets build

If Bash is available (Linux and Windows while on Git Bash), the commands will run in Bash, otherwise will fallback to cmd (on Windows).

Environment

You can specify environment variables that are added when running a command:

build:
  cmds:
  - echo $hallo
  env:
    hallo: welt

OS specific task support

If you add a Taskfile_{{GOOS}} you can override or amend your taskfile based on the op;erating system.

Example:

Taskfile.yml:

build:
  cmds:
  - echo  "default"

Taskfile_linux.yml:

build:
  cmds:
  - echo  "linux"

Will print out linux and not default

Running task in another dir

By default, tasks will be executed in the directory where the Taskfile is located. But you can easily make the task run in another folder informing dir:

js:
  dir: www/public/js
  cmds:
    - gulp

Task dependencies

You may have tasks that depends on others. Just pointing them on deps will make them run automatically before running the parent task:

build:
  deps: [assets]
  cmds:
    - go build -v -i main.go

assets:
  cmds:
    - gulp

In the above example, assets will always run right before build if you run task build.

A task can have only dependencies and no commands to group tasks together:

assets:
  deps: [js, css]

js:
  cmds:
    - npm run buildjs

css:
  cmds:
    - npm run buildcss

Each task can only be run once. If it is included from another dependend task causing a cyclomatic dependency, execution will be stopped.

task1:
  deps: [task2]

task2:
  deps: [task1]

Will stop at the moment the dependencies of task2 are executed.

Prevent task from running when not necessary

If a task generates something, you can inform Task the source and generated files, so Task will prevent to run them if not necessary.

build:
  deps: [js, css]
  cmds:
    - go build -v -i main.go

js:
  cmds:
    - npm run buildjs
  sources:
    - js/src/**/*.js
  generates:
    - public/bundle.js

css:
  cmds:
    - npm run buildcss
  sources:
    - css/src/*.css
  generates:
    - public/bundle.css

sources and generates should be file patterns. When both are given, Task will compare the modification date/time of the files to determine if it's necessary to run the task. If not, it will just print Task "js" is up to date.

You can use --force or -f if you want to force a task to run even when up-to-date.

Variables

build:
  deps: [setvar]
  cmds:
  - echo "{{.PREFIX}} {{.THEVAR}}"
  vars:
    PREFIX: "Path:"

setvar:
  cmds:
  - echo "{{.PATH}}"
  set: THEVAR

The above sample saves the path into a new variable which is then again echoed.

You can use environment variables, task level variables and a file called Taskvars.yml (or Taskvars.toml or Taskvars.json) as source of variables.

They are evaluated in the following order:

Task local variables are overwritten by variables found in Taskvars file. Variables found in Taskvars file are overwritten with variables from the environment. The output of the last command is stored in the environment. So you can do something like this:

build:
  deps: [setvar]
  cmds:
  - echo "{{.PREFIX}} '{{.THEVAR}}'"
  vars:
    PREFIX: "Result: "

setvar:
  cmds:
  - echo -n "a"
  - echo -n "{{.THEVAR}}b"
  - echo -n "{{.THEVAR}}c"
  set: THEVAR

The result of a run of build would be:

a
ab
abc
Result:  'abc'

Dynamic variables

If you prefix a variable with $, then the variable is considered a dynamic variable. The value after the $-symbol will be treated as a command and the output assigned.

build:
  cmds:
    - go build -ldflags="-X main.Version={{.LAST_GIT_COMMIT}}" main.go
  vars:
    LAST_GIT_COMMIT: $git log -n 1 --format=%h

Go's template engine

Task parse commands as Go's template engine before executing them. Variables are acessible through dot syntax (.VARNAME). The following functions are available:

• OS: return operating system. Possible values are "windows", "linux", "darwin" (macOS) and "freebsd".
• ARCH: return the architecture Task was compiled to: "386", "amd64", "arm" or "s390x".
• IsSH: on unix systems this should always return true. On Windows, will return true if sh command was found (Git Bash). In this case commands will run on sh. Otherwise, this function will return false meaning commands will run on cmd.

Example:

printos:
  cmds:
    - echo '{{OS}} {{ARCH}}'
    - "echo '{{if eq OS \"windows\"}}windows-command{{else}}unix-command{{end}}'"
    - echo 'Is SH? {{IsSH}}'

Alternatives

Similar software:

• tj/robo
• dogtools/dog