The BUILD ENV instruction tells the layerfile to rebuild when a variable changes.

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Examples

  • Commonly used with $SUBDOMAIN to ensure each branch has the proper value:
Layerfile
BUILD ENV SUBDOMAIN
RUN echo "HOST=$SUBDOMAIN.mydomain.com" >> .env
RUN docker-compose up -d

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Possible values

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SUBDOMAIN

SUBDOMAIN=my-branch

The SUBDOMAIN variable is often used to set the HOST variable for webservers.

It is a cleaned up version of the $GIT_BRANCH variable, acceptable for use in a URL.

  • feat/add-some-dashboard-pages becomes add-some-dashboard-pages

Common use is to set HOST=$SUBDOMAIN.demo.example.com

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DEPLOYMENT_HOST

DEPLOYMENT_HOST=job-5.demo.example.com

The DEPLOYMENT_HOST variable is set if a deployment exists for your run.

It’s often used to tell a webserver where it is being hosted.

If there are multiple deployments, a single one is returned.

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CI

CI=true, IS_CI_MACHINE=true, CI_MACHINE=true, IN_CI_MACHINE=true, IN_CI=true

These CI variables are always true while running a Layerfile.

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DEBIAN_FRONTEND

DEBIAN_FRONTEND=noninteractive

The DEBIAN_FRONTEND variable is always set to noninteractive in webapp.io. To change this behavior, use, e.g., ENV DEBIAN_FRONTEND=readline

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GIT_TAG

GIT_TAG=v1.0.0

GIT_TAG is the result of running git describe --always in the repository.

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GIT_COMMIT

GIT_COMMIT=111122223333444455556666777788889999aaaa

GIT_COMMIT is the result of running git rev-parse HEAD in the repository.

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GIT_SHORT_COMMIT

GIT_COMMIT=111122223333

GIT_COMMIT is the first 12 characters of running git rev-parse HEAD in the repository.

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GIT_COMMIT_TITLE

GIT_COMMIT_TITLE="[improvement] do something"

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GIT_CLONE_USER

GIT_CLONE_USER=x-access-token:<token>

GIT_CLONE_URL is a token which can be used to clone this repository. git clone https://[email protected]/org/repo.git

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EXPOSE_WEBSITE_HOST

EXPOSE_WEBSITE_HOST=(uuid).cidemo.co

EXPOSE_WEBSITE_HOST is the hostname exposed by EXPOSE WEBSITE

It’s often used to link a frontend with a backend when running both with EXPOSE WEBSITE and RUN BACKGROUND

You can even reference this before EXPOSE WEBSITE is ever used, but the URL is only live after the run passes.

Note: Unavailable for use by BUILD ENV

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WEBAPPIO

WEBAPPIO=true

WEBAPPIO is always true when running a Layerfile

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GIT_BRANCH

GIT_BRANCH=staging

GIT_BRANCH is the branch which is checked out in this repository.

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JOB_ID

JOB_ID=5

JOB_ID always exists. It’s set to the ID of the current running job.

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PULL_REQUEST_URL

PULL_REQUEST_URL=https://github.com/some/repo/pull_requests/5

PULL_REQUEST_URL may or may not exist. It’s a link to the pull request that triggered this pipeline.

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REPOSITORY_NAME

REPOSITORY_NAME=somerepo

REPOSITORY_NAME is the name of the repository. If the repository is at github.com/a/b, this would be “b”

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REPOSITORY_OWNER

REPOSITORY_OWNER=repoowner

REPOSITORY_OWNER is the name of the owner of this repository. If the repository is at github.com/a/b, this would be “a”

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ORGANIZATION_NAME

ORGANIZATION_NAME=myorg

ORGANIZATION_NAME is the name of the current organization. If the dashboard is at webapp.io/myorg, this would be “myorg”

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RUNNER_ID

RUNNER_ID=main-layerfile

RUNNER_ID is the id of the current layerfile runner.

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RETRY_INDEX

RETRY_INDEX=1

RETRY_INDEX is the current retry for the given runner (initially 1, then when retried once, 2, etc)

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API_EXTRA

API_EXTRA=some data passed from API

API_EXTRA is optional data passed in when a run is started by the API.

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