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How to set up continuous integration for a package with Wercker

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Set up continuous integration with Wercker

There are 2 major steps to set up continuous integration:

  • create a wercker.yml file in the package
  • add the application (package) to Wercker.com

To be able to add a package to Wercker, one must have administrator rights on the package repository on Github.

The Wercker test environment can only be set up if the file wercker.yml is commited to the repository, but Wercker is triggered to start checking when the application is added to wercker.com (giving an error if wercker.yml is not commited yet).

wercker.yml

Add a file “wercker.yml” in the root of the package with:

  • box: reference to a package with a Docker image that is used as a test environment. If no specific version is specified, only the last master version is used. Which Docker image to use?
    • inbobmk/rstable which is an image with stable versions of R and a large number of packages (see the README). Most of the packages which are often used at INBO are available. The version of the packages is roughly fixed to the date on which the R version in the Docker image was upgraded.
    • rocker/verse (https://hub.docker.com/r/rocker/verse/) which has the R, devtools and all tidyverse packages. The latest version of the image contains the latest version of the packages.
  • build:
    • different steps to pass
      • inbobmk/r-check: runs R CMD check but assumes that all dependencies are installed. Use this in combination with inbobmk/rstable in case you want to check your package against a stable set of packages.
      • jimhester/r-check: installs all missing dependencies on the fly and then runs R CMD check. This will install the latest version of the dependencies.
      • inbobmk/r-coverage: checks which lines in the code are covered by unit tests and which are not. See our page on code coverage for more details. This assumes that the covr package is installed.
      • jimhester/r-coverage: installs covr and runs the code coverage
      • inbobmk/r-lint: this check the style of your code. Good coding style is like using correct punctuation. You can manage without it, but it sure makes things easier to read. It assumes the lintr package is installed.
      • jimhester/r-lint: installs the lintr package and checks the style of the code
    • steps are run following their order in the yaml file
    • the execution will stop when a step fails
    • if not all packages are available in the docker image, code to install packages has to be added as a first step
  • after a build pipe, one can also add a deploy-pipe

An example of a simple wercker.yml-file:

box: inbobmk/rstable
build:
    steps:
        - script:
            code: Rscript -e "install.packages(c('DT','plotly'))"
        - inbobmk/r-check
        - inbobmk/r-coverage
        - inbobmk/r-lint

Wercker.com

To add the application to www.wercker.com:

  • log in on the website (easiest is to log in via github) and create a username
  • click on the “+” button on the right top and choose “add application”
  • select your username (next)
  • select the repository of your package (next)
  • choose the recommended option (next)
  • you could choose to make the results publicly available and “create”

After creation, one can under “options”:

  • pick a color for the package (useful when adding more than one package)
  • read information on Webhook (ensures communication between github, Wercker and other services)
  • status badge: markdown-code that allows you to add Wercker-results to your own code (e.g. copy this link to the README-file)

Hitting the avatar on the top right and choosing “Settings” allows to adjust if and when to receive email notifications.