If you cannot find a step which solves your particular “problem” in the Steps Registry, then you can create your own step and publish it. Steps are similar to any other projects on Wercker but instead of deploying to a cloud provider, you deploy to the step registry in order to make the step available.
To be able to publish a step, you first need a Wercker application containing the following files:
- The project needs to include a
run.shfile which is the entry-point of your step.
- The project needs to include a step manifest file call
Though technically a step can be written in any language, we recommended writing them in
bash or in
golang. The former is usually installed on most Docker containers whereas the latter compiles to a single binary. Both programming languages do not require any dependencies or libraries to be present that might not be installed in various Docker containers people use, making them quite portable. If you do create a step in a different programming language, and require certain run time components, make sure to document this in the step README.
The Step Manifest file
The step manifest file defines the configuration of your step. Below an example of a Wercker step manifest which we’ll go over:
name: slack-notifier version: 1.0.1 description: Posts Wercker build/deploy status to a Slack channel. keywords: - notification - webhook - slack properties: url: type: string required: true channel: type: string required: false username: type: string required: false notify_on: type: string default: all required: false icon_url: type: string required: false
name field is the name of your step. Together with your username this is the unique identifier of your step (
version field is the specific version of the step when deploying. This field needs to be unique for your step and must adhere to the semantic version scheme. Your first version would be
0.1.0 and each minor change would bump up the last digit by one.
version are required. All the following properties are optional, though we encourage people to use them.
description field is the description for the step. We recommend using a small single line or single paragraph description, all other documentation should be in the
keywords fields contains an array of strings with keywords of this step. We recommend a few tags (at most 5) to describe the step.
properties field contains metadata describing the parameters that are available for the step. This is a map, where the key is the name of the step, and the value is a object with the following properties:
type- the type of the data of the parameter. Currently supported:
required- boolean indicating if the parameter is required or not (currently not enforced).
default- value that gets used, if no parameter was provided through the Wercker.yml
The run.sh file
run.sh file contains the entrypoint your step logic. This should be
bash code in the
run.sh file itself. If you want to create a more complex application in a different language, than call this from within the
For each property you specified in your
wercker-step.yml, Wercker sets a corresponding environment variable. For example, the value of the
url property would be made available in the
$WERCKER_SLACK_NOTIFIER_URL environment variable.
Notice that any hyphens you use in your parameter names will be transformed to underscores.
README.md is present in your step folder, the registry will display this such that people can easily deduct what your step does and how to use it.
Publishing your step
Publishing steps is done by
deploying your step to the registry. To do so create a project on Wercker for your step by going to "Create" and selecting "Step" from the dropdown:
The build process will run in the same way as any other application on Wercker. You can then publish the step by selecting "publish step" from the "deploy to" drop-down of any green build:
You can check out the complete repository of the Wercker Kubectl step on GitHub