Introduction to Taskfile: a Makefile alternative

Sébastien Kurtzemann — Fri, 11 Jun 2021 14:58:30 +0000

Makefile are often used to build assets from source code.

You can also use them to automate common and repetitive tasks. Building containers or perform some Terraform operations are some examples.

But, when comes the need to create some documentation about available targets or add new tasks, it can become more difficult.

Few years ago, I discovered Task who describe itself as:

Task is a task runner / build tool that aims to be simpler and easier to use than, for example, GNU Make.

In this post, I will introduce this tool and go throught the most common uses I had with it.

Installing task

Several methods are available in the official installation section.

On macOS, simply use Homebrew

brew install go-task/tap/go-task

Create a task to build a container

One use case I got very often, is to build containers from a Dockerfile.

The 3 most common operations I did are

building the container image
pushing the built image to a Registry
log into an instance of the container image (for some tests, etc.)

Define the `build` task

For this, we just need a basic Taskfile.yml with the below content

version: "3"

tasks:
    build:
        desc: Build the container image
        cmds:
        - docker build -t mycontainerimage -f Dockerfile .

Under the tasks parameter, we declare a task named build with 2 parameters desc and cmds.

Then, we just run task --list

Λ\: task --list
task: Available tasks for this project:
* build:    Build the container image

And if we run task build, it returns

Λ\: task build
task: [build] docker build -t mycontainerimage -f Dockerfile .
[...]

This is pretty simple

desc is the task description
cmds are commands you want to run

Add more operations

Sometimes before pushing the built container, you need to log into an instance to test some stuff... So, how can we add this operation?

But wait... the container image name will be the same between build and enter tasks... Let's introduces some variables.

version: "3"

vars:
    CONTAINER_IMAGE: mycontainerimage

tasks:
    build:
        desc: Build the container image
        cmds:
        - docker build -t {{.CONTAINER_IMAGE}} -f Dockerfile .

    enter:
        desc: Enter into the built container
        cmds:
        - docker run -it --rm --entrypoint=sh {{.CONTAINER_IMAGE}}

Now task --list returns

Λ\: task --list
task: Available tasks for this project:
* build:    Build the container image
* enter:    Enter into the built container

And we can easily add, a new task, for the push operation

version: "3"

vars:
    CONTAINER_IMAGE: mycontainerimage

tasks:
    build:
        desc: Build the container image
        cmds:
        - docker build -t {{.CONTAINER_IMAGE}} -f Dockerfile .

    enter:
        desc: Enter into the built container
        cmds:
        - docker run -it --rm --entrypoint=sh {{.CONTAINER_IMAGE}}

    push:
        desc: Push built image
        cmds:
        - docker push {{.CONTAINER_IMAGE}}

Variables

Variables can also be assigned dynamically and be nested.

For example, if we want to set image tag to the current git commit

version: "3"

vars:
    CONTAINER_IMAGE_NAME: mycontainerimage
    CONTAINER_IMAGE_TAG: {sh: git-rev parse HEAD}
    CONTAINER_IMAGE: "{{.CONTAINER_IMAGE_NAME}}:{{.CONTAINER_IMAGE_TAG}}"

tasks:
    build:
        desc: Build the container image
        cmds:
        - docker build -t {{.CONTAINER_IMAGE}} -f Dockerfile .

    enter:
        desc: Enter into the built container
        cmds:
        - docker run -it --rm --entrypoint=sh {{.CONTAINER_IMAGE}}

    push:
        desc: Push built image
        cmds:
        - docker push {{.CONTAINER_IMAGE}}

Because Task is built in Golang, some Go template functions can be used to defined variables or commands:

vars:
    CURRENT_TIME: {{now | date "2006-01-02"}}

A step further

Another use case I often had, is to create infrastucture resources and then init/provison them.

For this example I will

use Terraform to create infrastructure (a Kubernetes cluster)
then install ingress-nginx Helm package

By design, I will put

Terraform files into a terraform/ folder
Helm releases definition into a releases/ folder

Here the structure, no matter the files content

.
├── releases
│   └── helmfile.yaml
└── terraform
    └── main.tf

Create actions

I will create

3 actions for Terraform operations : init, plan and apply
2 actions for Helm releases : diff, apply (I use helmfile to install Helm release)

Let's create a naive Taskfile.yml

version: "3"

vars:
  TFPLAN: .tfplan

tasks:
  init:
    dir: terraform/
    desc: Init terraform
    cmds:
      - terraform init

  plan:
    dir: terraform/
    desc: Show terraform resources creation
    cmds:
      - terraform plan -out={{.TFPLAN}}

  apply:
    dir: terraform/
    desc: Apply resources creation
    cmds:
      - terraform apply "{{.TFPLAN}}"

  diff:
    dir: releases/
    desc: Show releases diff
    cmds:
      - helmfile diff

  apply:
    dir: releases/
    desc: Apply releases
    cmds:
      - helmfile apply

We introduce a new parameter dir, which specified where to run cmds.

But we have a problem, 2 tasks have the same name! So just add a prefix

version: "3"

vars:
  TFPLAN: .tfplan

tasks:
  init:
    dir: terraform/
    desc: Init terraform
    cmds:
      - terraform init

  plan:
    dir: terraform/
    desc: Show terraform resources creation
    cmds:
      - terraform plan -out={{.TFPLAN}}

  terraform-apply:
    dir: terraform/
    desc: Apply resources creation
    cmds:
      - terraform apply "{{.TFPLAN}}"

  diff:
    dir: releases/
    desc: Show releases diff
    cmds:
      - helmfile diff

  releases-apply:
    dir: releases/
    desc: Apply releases
    cmds:
      - helmfile apply

Then try task --list

Λ\: task --list
task: Available tasks for this project:
* diff:         Show releases diff
* init:         Init terraform
* plan:         Show terraform resources creation
* releases-apply:   Apply releases
* terraform-apply:  Apply resources creation

It's working, but not good enough to understand which actions goes with each group.

A better usage will be to add a namespace

version: "3"

vars:
  TFPLAN: .tfplan

tasks:
  terraform:init:
    dir: terraform/
    desc: Init terraform
    cmds:
      - terraform init

  terraform:plan:
    dir: terraform/
    desc: Show terraform resources creation
    cmds:
      - terraform plan -out={{.TFPLAN}}

  terraform:apply:
    dir: terraform/
    desc: Apply resources creation
    cmds:
      - terraform apply "{{.TFPLAN}}"

  releases:diff:
    dir: releases/
    desc: Show releases diff
    cmds:
      - helmfile diff

  releases:apply:
    dir: releases/
    desc: Apply releases
    cmds:
      - helmfile apply

And task --list returns

task: Available tasks for this project:
* releases:apply:   Apply releases
* releases:diff:    Show releases diff
* terraform:apply:  Apply resources creation
* terraform:init:   Init terraform
* terraform:plan:   Show terraform resources creation

But over time, this Taskfile.yml will become huge!

A better approach

A feature I really like in Task is including others taskfiles.

Let's add another folder: taskfiles/, with 2 files in it

terraform.yml
helmfile.yml

.
├── releases
│   └── helmfile.yaml
├── taskfiles
│   ├── helmfile.yml
│   └── terraform.yml
└── terraform
    └── main.tf

Let's see the content of each files

releases/terraform.yml

version: "3"

vars:
  TFPLAN: .tfplan

tasks:
  init:
    dir: terraform/
    desc: Init terraform
    cmds:
      - terraform init

  plan:
    dir: terraform/
    desc: Show terraform resources creation
    cmds:
      - terraform plan -out={{.TFPLAN}}

  apply:
    dir: terraform/
    desc: Apply resources creation
    cmds:
      - terraform apply "{{.TFPLAN}}"

releases/helmfile.yml

version: "3"

tasks:
  diff:
    dir: releases/
    desc: Show releases diff
    cmds:
      - helmfile diff

  apply:
    dir: releases/
    desc: Apply releases
    cmds:
      - helmfile apply

As we can see, it looks very similar, but without namespaces.

What is now the main Taskfile.yml content ?

version: "3"

includes:
  tf: ./taskfiles/terraform.yml
  releases: ./taskfiles/helmfile.yml

If we run task --list we got the same result

task: Available tasks for this project:
* releases:apply:   Apply releases
* releases:diff:    Show releases diff
* tf:apply:         Apply resources creation
* tf:init:      Init terraform
* tf:plan:      Show terraform resources creation

As you can see, includes

make the "main" Taskfile.yml easier to read
give the ability to define namespaces independently of included files names
offer better tasks organization with dedicated files

And more...

Others functionalities are also available

prevent unnecessary work using sources and generates parameters
dependency management with deps
watching files changes to run tasks again
etc.

Conclusion

Launching repetitive commands every day is painful, Makefile are great to avoid this.

In this article, we discovered Task as a make alternative, with similar functionalities but I think easier to use.

Forem: Sébastien Kurtzemann