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Fetching external dependencies

Kapitan is capable of fetching components stored in remote locations. This feature can be used by specifying those dependencies in the inventory under parameters.kapitan.dependencies. Supported types are:

Some use cases of this feature may include:

  • using templates/jsonnet libraries hosted remotely
  • using values in remote files via file_read jsonnet callback

Usage

parameters:
  kapitan:
    dependencies:
    - type: <dependency_type>
      output_path: path/to/file/or/dir
      source: <source_of_dependency>
      # other type-specific parameters, if any

Use --fetch option to fetch the dependencies:

$ kapitan compile --fetch

This will download the dependencies and store them at their respective output_path. By default, kapitan does not overwrite existing items with the same name as that of the fetched dependencies.

Use the --force flag to force fetch (update cache with freshly fetched dependencies) and overwrite any existing item sharing the same name in the output_path.

$ kapitan compile --fetch --force

Use the --cache flag to cache the fetched items in the .dependency_cache directory in the root project directory.

$ kapitan compile --cache --fetch

Git type

Git types can fetch external dependencies available via HTTP/HTTPS or SSH URLs. This is useful for fetching repositories or their sub-directories, as well as accessing them in specific commits and branches (refs).

Note: git types require git binary on your system.

Usage

parameters:
  kapitan:
    dependencies:
    - type: git
      output_path: path/to/dir
      source: git_url
      subdir: relative/path/from/repo/root (optional)
      ref: tag, commit, branch etc. (optional)

Example

Say we want to fetch the source code from our kapitan repository, specifically, kapicorp/kapitan/kapitan/version.py. Let's create a very simple target file inventory/targets/kapitan-example.yml.

parameters:
  kapitan:
    vars:
      target: kapitan-example
    dependencies:
    - type: git
      output_path: source/kapitan
      source: [email protected]:kapicorp/kapitan.git
      subdir: kapitan
      ref: master
    compile:
    - input_paths:
      - source/kapitan/version.py
      input_type: jinja2 # just to copy the file over to target
      output_path: .

Then run:

$ kapitan compile --fetch -t kapitan-example
Dependency [email protected]:kapicorp/kapitan.git : fetching now
Dependency [email protected]:kapicorp/kapitan.git : successfully fetched
Dependency [email protected]:kapicorp/kapitan.git : saved to source/kapitan
Compiled kapitan-example (0.02s)

$ ls source
kapitan

This will download the kapitan repository (kapicorp/kapitan), copy the sub-directory kapitan and save it to source/kapitan. Therefore, kapicorp/kapitan/kapitan corresponds to source/kapitan locally.

Note that even if you are not using subdir parameter, you can and should specify the repository name in the output_path parameter. If you only specify source as the output_path, then all the kapitan files will be under source and not source/kapitan.

HTTP type

http[s] types can fetch external dependencies available at http:// or https:// URL.

Usage

parameters:
  kapitan:
    dependencies:
    - type: http | https
      output_path: path/to/file
      source: http[s]://<url>
      unpack: True | False

output_path must fully specify the file name. For example:

parameters:
  kapitan:
    dependencies:
    - type: https
      output_path: foo.txt
      source: https://example.com/foo.txt

Example

Say we want to download kapitan README.md file. Since it's on Github, we can access it as https://raw.githubusercontent.com/kapicorp/kapitan/master/README.md. Using the following inventory, we can copy this to our target folder:

parameters:
  kapitan:
    vars:
      target: kapitan-example
    dependencies:
    - type: https
      output_path: README.md
      source: https://raw.githubusercontent.com/kapicorp/kapitan/master/README.md
    compile:
    - input_paths:
      - README.md
      input_type: jinja2
      output_path: .

Then run:

$ kapitan compile --fetch -t kapitan-example
Dependency https://raw.githubusercontent.com/kapicorp/kapitan/master/README.md : fetching now
Dependency https://raw.githubusercontent.com/kapicorp/kapitan/master/README.md : successfully fetched
Dependency https://raw.githubusercontent.com/kapicorp/kapitan/master/README.md : saved to README.md
Compiled kapitan-example (0.02s)

$ ls
compiled inventory README.md

This fetches the README.md file from the URL and save it locally.

Another use case for http types is when we want to download an archive file, such as helm packages, and extract its content. Setting unpack: True will unpack zip or tar files onto the output_path. In such cases, set output_path to a folder where you extract the content, and not the file name. You can refer to here for the example.

Helm type

Fetches helm charts and any specific subcharts in the requirements.yaml file. Currently only works on linux with the helm_fetch_binding.

Usage

parameters:
  kapitan:
    dependencies:
    - type: helm
      output_path: path/to/chart
      source: http[s]://<helm_chart_repository_url>
      version: <specific chart version>
      chart_name: <name of chart>

Example

If we want to download the prometheus helm chart we simply add the dependency to the monitoring target. We want a specific version 11.3.0 so we put that in.

parameters:
  kapitan:
    vars:
      target: monitoring
    dependencies:
      - type: helm
        output_path: charts/prometheus
        source: https://kubernetes-charts.storage.googleapis.com
        version: 11.3.0
        chart_name: prometheus
    compile:
      - input_type: helm
        output_path: .
        input_paths:
          - charts/prometheus
        helm_values:
      	  alertmanager:
            enabled: false
        helm_params:
          namespace: monitoring
          name_template: prometheus
          release_name: prometheus

Then run:

$ kapitan compile --fetch -t monitoring
Dependency helm chart prometheus and version 11.3.0: fetching now
Dependency helm chart prometheus and version 11.3.0: successfully fetched
Dependency helm chart prometheus and version 11.3.0: saved to charts/prometheus
Compiled monitoring (1.48s)

$ tree -L 3
├── charts
│   └── prometheus
│       ├── Chart.yaml
│       ├── README.md
│       ├── charts
│       ├── requirements.lock
│       ├── requirements.yaml
│       ├── templates
│       └── values.yaml
├── compiled
│   ├── monitoring
├── inventory
    ├── classes
        ├── common.yml
        ├── component

If you simply want the latest chart available, either don't include the version key or specify an empty string.

parameters:
  kapitan:
    vars:
      target: monitoring
    dependencies:
      - type: helm
        output_path: charts/prometheus
        source: https://kubernetes-charts.storage.googleapis.com
        version: ""
        chart_name: prometheus
    compile:
      - input_type: helm
        output_path: .
        input_paths:
          - charts/prometheus
        helm_values:
      	  alertmanager:
            enabled: false
        helm_params:
          namespace: monitoring
          name_template: prometheus
          release_name: prometheus

Then run:

$ kapitan compile --fetch -t monitoring
Dependency helm chart prometheus being fetch with using latest version available
Dependency helm chart prometheus and version : fetching now
Dependency helm chart prometheus and version : successfully fetched
Dependency helm chart prometheus and version : saved to charts/prometheus
Compiled monitoring (1.58s)

$ tree -L 3
├── charts
│   └── prometheus
│       ├── Chart.yaml
│       ├── README.md
│       ├── charts
│       ├── requirements.lock
│       ├── requirements.yaml
│       ├── templates
│       └── values.yaml
├── compiled
│   ├── monitoring
├── inventory
    ├── classes
        ├── common.yml
        ├── component