skaffold-generator

CLI tool to generate skaffold.yaml to build and deploy only required services

Motivation

When we migrate Docker Compose to Skaffold to develop k8s application at local, Skaffold doesn't provide some features which Docker Compose provides.

• Launch only specified services (docker-compose up [<service name> ...])
• Manage dependencies (depends_on)

Please imagine that many microservices are managed by one skaffold.yaml. When we develop a service A, it is convenient to build and deploy only the service A and services which the service A depends on.

So this tool skaffold-generator provides these features.

skaffold-generator watches the configuration file skaffold-generator.yaml and updates skaffold.yaml every time skaffold-generator.yaml is updated.

In skaffold-generator.yaml, we can define services and each service's artifacts and manifests, and service dependencies.

The command skaffold-generator takes service names as arguments, and generate skaffold.yaml only for the specified services.

Even if over one hundred services are defined in skaffold-generator.yaml, when we run slaffold-generator blog, skaffold.yaml is generated based on only the service blog and services which blog depends on.

skaffold-generator doesn't use skaffold. skaffold-generator just update skaffold.yaml. By running skaffold dev while running skaffold-generator, skaffold dev detects the update by skaffold-generator and updates application actually.

Status

Currently, this tool only supports to overwrite deploy.kubectl.manifests and build.artifacts.

Install

Download the binary from the release page.

Getting Started

$ git clone https://github.com/suzuki-shunsuke/skaffold-generator
$ cd skaffold-generator/examples
$ tree
.
├── api
│   └── Dockerfile
├── api.yaml
├── foo
│   └── Dockerfile
├── foo.yaml
├── mongodb.yaml
├── skaffold-generator.yaml
└── skaffold.yaml

2 directories, 7 files

Currently, skaffold.yaml doesn't exist. Let's run skaffold-generator.

$ skaffold-generator
2020/04/05 18:19:37 start to watch skaffold-generator.yaml

skaffold-generator watches the update of skaffold-generator.yaml until Ctrl-C is clicked.

On the other terminal, please confirm skaffold.yaml is generated.

When skaffold-generator doesn't take any arguments, skaffold.yaml is generated based on all services.

Let's change the image name foo to bar, and confirm that skaffold-generator detect the change and skaffold.yaml is updated.

$ skaffold-generator
2020/04/05 18:19:37 start to watch skaffold-generator.yaml
2020/04/05 18:27:17 detect the update of skaffold-generator.yaml

After confirmation, please reset the change of image name.

By running skaffold dev, we can build and deploy applications with Skaffold.

$ skaffold dev

Once stop the command skaffold-generator by clicking Ctrl-C, and rerun skaffold-generator with arguments.

$ skaffold-generator api
2020/04/05 18:40:31 start to watch skaffold-generator.yaml

The argument api is a service name. We can confirm that skaffold.yaml is updated and artifacts and manifests about foo are removed. We don't specify mongodb by arguments but the service api depends on mongodb so artifacts and manifests of mongodb are also included in skaffold.yaml.

Usage

$ skaffold-generator --help
NAME:
   skaffold-generator - generate skaffold.yaml

USAGE:
   skaffold-generator [global options] [arguments...]

VERSION:
   0.1.0-0

GLOBAL OPTIONS:
   --src value, -s value   configuration file path (skaffold-generator.yaml) (default: "skaffold-genera
tor.yaml")
   --dest value, -d value  generated configuration file path (skaffold.yaml) (default: "skaffold.yaml")
   --help, -h              show help (default: false)
   --version, -v           print the version (default: false)

Configuration

skaffold-generator.yaml

---
services:
- name: mongodb # service name. This is used to specify the service by command line arguments and depends_on
  manifests: # skaffold.yaml's `deploy.kubectl.manifests`
    - "mongodb.yaml"
  artifacts: # skaffold.yaml's `build.artifacts`
    - image: mongodb
      context: .
      docker:
        dockerfile: mongodb/Dockerfile
      sync:
        infer:
          - 'mongodb/etc/**/*'
- name: api
  depends_on: # service names which this service depends on
    - mongodb
  manifests:
    - "api.yaml"
  artifacts:
    - image: api
      context: .
      docker:
        dockerfile: api/Dockerfile
# base `skaffold.yaml`.
# `deploy.kubectl.manifests` and `build.artifacts` are overwritten.
base:
  apiVersion: skaffold/v2alpha4
  kind: Config

Change detection

To detect the update of skaffold-generator.yaml, we use the third party library github.com/radovskyb/watcher.

License

MIT