werf.yaml

Project name

project defines unique project name of your application. Project name affects build cache image names, Kubernetes Namespace, Helm release name and other derived names. This is a required field of meta configuration.

Project name should be unique within group of projects that shares build hosts and deployed into the same Kubernetes cluster (i.e. unique across all groups within the same gitlab). Project name must be maximum 50 chars, only lowercase alphabetic chars, digits and dashes are allowed.

Warning on changing project name

WARNING. You should never change project name, once it has been set up, unless you know what you are doing. Changing project name leads to issues:

1. Invalidation of build cache. New images must be built. Old images must be cleaned up from local host and container registry manually.
2. Creation of completely new Helm release. So if you already had deployed your application, then changed project name and deployed it again, there will be created another instance of the same application.

werf cannot automatically resolve project name change. Described issues must be resolved manually in such case.

Deploy

Helm chart dir

Specify custom directory to the helm chart of the project, for example .deploy/chart:

deploy:
  helmChartDir: .deploy/chart

Release name

werf allows to define a custom release name template, which used during deploy process to generate a release name:

project: PROJECT_NAME
configVersion: 1
deploy:
  helmRelease: TEMPLATE
  helmReleaseSlug: false

deploy.helmRelease is a Go template with [[ and ]] delimiters. There are [[ project ]], [[ env ]] functions support. Default: [[ project ]]-[[ env ]]. Template can be customized as follows:

deploy:
  helmRelease: >-
    [[ project ]]-{{ env "HELM_RELEASE_EXTRA" }}-[[ env ]]

NOTE. Usage of the HELM_RELEASE_EXTRA environment variable should be allowed explicitly in the werf-giterminism.yaml configuration in that case.

deploy.helmReleaseSlug defines whether to apply or not slug to generated helm release name. Default: true.

Kubernetes namespace

werf allows to define a custom Kubernetes namespace template, which used during deploy process to generate a Kubernetes Namespace:

project: PROJECT_NAME
configVersion: 1
deploy:
  namespace: TEMPLATE
  namespaceSlug: true|false

deploy.namespace is a Go template with [[ and ]] delimiters. There are [[ project ]], [[ env ]] functions support. Default: [[ project ]]-[[ env ]]. Template can be customized as follows:

deploy:
  namespace: >-
    [[ project ]]-[[ env ]]

deploy.namespaceSlug defines whether to apply or not slug to generated kubernetes namespace. Default: true.

Cleanup

Configuring cleanup policies

The cleanup configuration consists of a set of policies called keepPolicies. They are used to select relevant images using the git history. Thus, during a cleanup, images not meeting the criteria of any policy are deleted.

Each policy consists of two parts:

• references defines a set of references, git tags, or git branches to perform scanning on.
• imagesPerReference defines the limit on the number of images for each reference contained in the set.

Each policy should be linked to some set of git tags (tag: string || /REGEXP/) or git branches (branch: string || /REGEXP/). You can specify the name/group of a reference using the Golang’s regular expression syntax.

tag: v1.1.1
tag: /^v.*$/
branch: master
branch: /^(master|production)$/

When scanning, werf searches for the provided set of git branches in the origin remote references, but in the configuration, the origin/ prefix is omitted in branch names.

You can limit the set of references on the basis of the date when the git tag was created or the activity in the git branch. The limit group of parameters allows the user to define flexible and efficient policies for various workflows.

- references:
    branch: /^features\/.*/
    limit:
      last: 10
      in: 168h
      operator: And

In the example above, werf selects no more than 10 latest branches that have the features/ prefix in the name and have shown any activity during the last week.

• The last: int parameter allows you to select n last references from those defined in the branch / tag.
• The in: duration string parameter (you can learn more about the syntax in the docs) allows you to select git tags that were created during the specified period or git branches that were active during the period. You can also do that for the specific set of branches / tags.
• The operator: And || Or parameter defines if references should satisfy both conditions or either of them (And is set by default).

When scanning references, the number of images is not limited by default. However, you can configure this behavior using the imagesPerReference set of parameters:

imagesPerReference:
  last: int
  in: duration string
  operator: And || Or

• The last: int parameter defines the number of images to search for each reference. Their amount is unlimited by default (-1).
• The in: duration string parameter (you can learn more about the syntax in the docs) defines the time frame in which werf searches for images.
• The operator: And || Or parameter defines what images will stay after applying the policy: those that satisfy both conditions or either of them (And is set by default).

In the case of git tags, werf checks the HEAD commit only; the value of last>1 does not make any sense and is invalid

When describing a group of policies, you have to move from the general to the particular. In other words, imagesPerReference for a specific reference will match the latest policy it falls under:

- references:
    branch: /.*/
  imagesPerReference:
    last: 1
- references:
    branch: master
  imagesPerReference:
    last: 5

In the above example, the master reference matches both policies. Thus, when scanning the branch, the last parameter will equal to 5.

Default policies

If there are no custom cleanup policies defined in werf.yaml, werf uses default policies configured as follows:

cleanup:
  keepPolicies:
  - references:
      tag: /.*/
      limit:
        last: 10
  - references:
      branch: /.*/
      limit:
        last: 10
        in: 168h
        operator: And
    imagesPerReference:
      last: 2
      in: 168h
      operator: And
  - references:  
      branch: /^(master|staging|production)$/
    imagesPerReference:
      last: 10

Let us examine each policy individually:

1. Keep an image for the last 10 tags (by date of creation).
2. Keep no more than two images published over the past week, for no more than 10 branches active over the past week.
3. Keep the 10 latest images for master, staging, and production branches.

Git worktree

werf stapel builder needs a full git history of the project to perform in the most efficient way. Based on this the default behaviour of the werf is to fetch full history for current git clone worktree when needed. This means werf will automatically convert shallow clone to the full one and download all latest branches and tags from origin during cleanup process.

Default behaviour described by the following settings:

gitWorktree:
  forceShallowClone: false
  allowUnshallow: true
  allowFetchOriginBranchesAndTags: true

For example to disable automatic unshallow of git clone use following settings:

gitWorktree:
  forceShallowClone: true
  allowUnshallow: false

Image section

Images are declared with image directive: image: string. The image directive starts a description for building an application image.

image: frontend

If there is only one image in the config, it can be nameless:

image: ~

In the config with multiple images, all images must have names:

image: frontend
...
---
image: backend
...

An image can have several names, set as a list in YAML syntax (this usage is equal to describing similar images with different names):

image: [main-front,main-back]

You will need an image name when setting up helm templates or running werf commands to refer to the specific image defined in the werf.yaml.

Dockerfile builder

werf supports building images using Dockerfile. Building an image from Dockerfile is the easiest way to start using werf in an existing project.

werf.yaml below describes an unnamed image built from Dockerfile which reside in the root of the project dir:

project: my-project
configVersion: 1
---
image: ~
dockerfile: Dockerfile

To build multiple named stages from a single Dockerfile:

image: backend
dockerfile: Dockerfile
target: backend
---
image: frontend
dockerfile: Dockerfile
target: frontend

And also build multiple images from different Dockerfiles:

image: backend
dockerfile: backend/Dockerfile
context: backend/
---
image: frontend
dockerfile: frontend/Dockerfile
context: frontend/

contextAddFiles

The build context consists of the files from a directory, defined by context directive (the project directory by default), from the current project git repository commit.

The contextAddFiles directive allows adding of arbitrary files or directories from the project directory to the build context.

image: app
context: app
contextAddFiles:
 - file1
 - dir1/
 - dir2/file2.out

The configuration describes the build context that consists of the following files:

• app/**/* from the current project git repository commit;
• Files app/file1, app/dir2/file2.out and directory dir1 from the project directory.

The contextAddFiles files have a higher priority than the files from the current project git repository commit. When these files are crossing, the user will work with files from the project directory.

By default, the use of the contextAddFiles directive is not allowed by giterminism (read more about it here)

Stapel builder

Another alternative to building images with Dockerfiles is werf stapel builder, which is tightly integrated with Git and allows really fast incremental rebuilds on changes in the Git files.