> [Introduced][ce-21971] in GitLab 8.12. Further additions were made in GitLab 8.13.
>
Inspired by [Heroku's Review Apps][heroku-apps] which itself was inspired by
[Fourchette].
Review apps are automatically-created [environments] that run your code for each
branch. That means [merge requests] can be reviewed in a live-running environment.
The base of Review Apps is the [dynamic environments] which allow you to create
a new environment (dynamically) for each one of your branches.
They mostly make sense to be used with web applications.
A Review App can then be visible as a link when you visit the [merge request]
relevant to the branch. That way, you are able to see live all changes introduced
by the merge request changes. Reviewing anything, from performance to interface
changes, becomes much easier with a live environment and as such, Review Apps
can make a huge impact on your development flow.
Review Apps can make a huge impact on your development flow. Reviewing anything
from performance to interface changes becomes much easier with a live environment.
They mostly make sense to be used with web applications, but you can use them
any way you'd like.
>
Inspired by [Heroku's Review Apps][heroku-apps] which itself was inspired by
[Fourchette].
## Overview
Simply put, a Review App is a mapping of
a branch with an environment as there is a 1:1 relation between them.
To get a better understanding of Review Apps, you must first learn how
environments and deployments work. The following docs will help you grasp that
knowledge:
1. First, learn about [environments][] and their role in the development workflow.
1. Then make a small stop to learn about [CI variables][variables] and how they
can be used in your CI jobs.
1. Next, explore the [`environment` syntax][yaml-env] as defined in `.gitlab-ci.yml`.
This will be your primary reference when you are finally comfortable with
how environments work.
1. Additionally, find out about [manual actions][] and how you can use them to
deploy to critical environments like production with the push of a button.
1. And as a last step, follow the [NGINX example tutorial][app-nginx] which will
guide you step by step to set up the infrastructure and make use of
Review Apps with a simple HTML site and NGINX.
## Configuration
For configuration examples see the [dynamic environments] documentation.
## Creating and destroying Review Apps
The creation and destruction of a Review App is defined in `.gitlab-ci.yml`.
Check the [environments] documentation how to do so.
## A simple workflow
The process of adding Review Apps in your workflow would look like:
1. Set up the infrastructure to host and deploy the Review Apps.
1. Install and configure a Runner that does the deployment.
1. Set up a job in `.gitlab-ci.yml` that uses the predefined
[predefined CI environment variable][variables]`${CI_BUILD_REF_NAME}` to
create dynamic environments and restrict it to run only on branches.
1. Optionally set a job that stops the Review Apps.
From there on, you would follow the branched Git flow:
1. Push a branch and let the Runner deploy the Review App based on the `script`
definition of the dynamic environment job.
1. Wait for the Runner to build and/or deploy your web app.
1. Click on the link that's present in the MR related to the branch and see the
changes live.
### Limitations
We are limited to use only [CI predefined variables][variables].
## Dynamic environments
## Examples
A list of examples used with Review Apps can be found below:
You can now use predefined CI variables as a name for environments. In addition,
you can specify a URL for the environment configuration in your .gitlab-ci.yml
file.
-[Use with NGINX][app-nginx] - Use NGINX and the shell executor of GitLab Runner
to deploy a simple HTML website.
- Mapping branch with environment
And below is a soon to be added examples list:
This issue describes dynamic environments implementation, mostly to be used with dynamically create applications.
These application will be mostly used for Review Apps.
- Use with Amazon S3
- Use on Heroku with dpl
- Use with OpenShift/kubernetes
## Assumptions
...
...
@@ -34,23 +92,10 @@ These application will be mostly used for Review Apps.
1. We need some form to distinguish between production/staging and review app environment,
1. We don't try to manage life cycle of deployments in the first iteration, possibly we will extend a Pipeline to add jobs that will be responsible either for cleaning up or removing old deployments and closing environments.
## Configuration
```
review_apps:
environment:
name: review/$CI_BUILD_REF_NAME
url: http://$CI_BUILD_REF_NAME.review.gitlab.com/
```
### Remarks
1. We are limited to use only CI predefined variables, since this is not easy task to pass the URL from build,
2. I do prefer nested `url:` since this allows us in the future to extend that with more `environment:` configuration or constraints, like: `required_variables:` or `access_level` of user allowed to use that.
3. Following the problem from (1) we can extend `url:` with a `regexp` that will be used to fish a URL from build log.
## Distinguish between production and review apps
- Are dynamic environments distinguishable by the slash in `environment:url`?
### Convention over configuration
We would expect the environments to be of `type/name`:
...
...
@@ -65,18 +110,13 @@ The `type/name` also plays nice with `Variables` and `Runners`, because we can l
1. We could extend the resources with a field that would allow us to filter for what types it can be used, ex.: `production/*` or `review-apps/*`
2. We could limit runners to be used only by `review-apps/*`,
