Have you ever wanted to run an automated DevOps pipeline not only for
git push, but also in response to an external event?
Then you are in the right place. With Codefresh pipelines you can execute pipelines in response to external events.
The first event we are adding support to, is a Docker Hub
When a new Docker image is pushed to Docker Hub we can trigger a webhook to execute CD pipelines.
Continuous Delivery Pipelines
When constructing Continuous Delivery pipelines and selecting a pipeline orchestration engine, you should consider the following things.
Find a robust orchestration engine
There are multiple engines to select from and you are can choose whatever you are familiar with, or the one that is easy to learn and extend.
But it’s critical, that the orchestration engine you select supports event-driven pipeline execution. These events should not only be “code related events”, but can also trigger CD pipeline.
Some examples of engines are:
- GitHub Release
- Docker Hub push
- S3 bucket update
- Kubernetes deployment update
- Periodic/cron timer and etc.
Most of the multiple orchestration engines mentioned above, are tuned to continuous integration use cases where your pipeline runs only when new code is pushed into a code repository. However, when you want to trigger pipeline execution with something other than a
git push event, it requires a lot of custom development and scripting. It’s also hard to setup and maintain it over time.
Therefore, in Codefresh, we have re-evaluated our approach to pipelines and changed our system to be easily adaptable to external events.
Codefresh container-based pipelines
Codefresh container-based pipelines allow the automation of multiple DevOps tasks, like build, test, analyze, deploy, configure, and release software service. We already support triggering pipelines based on push events with integrations into the most popular git services such as: GitHub, Bitbucket or GitLab.
As a user, you can start Codefresh pipeline execution manually or by using the Codefresh CLI tool.
To extend our support of Continuous Delivery use cases, we are adding support for external triggers starting with Docker Hub
push event and adding more events such as:
- Generic webhooks
- Cron timers,
- Object storage updates,
pushfrom other Docker registries, and more.
We are also planning to open Codefresh triggers and allow our users to add support for events from other systems.
Triggering Codefresh Pipelines
Our first trigger allows triggering Codefresh pipeline execution when a new Docker image is pushed (or tagged) in a Docker Hub repository.
For this demo, I’m using the codefresh/fortune Docker image. It’s a small Alpine based image that contains a single “fortune” phrase (
/fortune.txt file), automatically generated for each image build.
Codefresh exposes a web method endpoint for accepting Docker Hub webhook payload. It parses Docker Hub event and passes information about this event into a connected Codefresh pipeline, together with original webhook
Note: Currently, we support setting Codefresh pipeline execution trigger only through the API and
codefresh command line tool.
Installing Codefresh CLI tool
Codefresh CLI allows you to work with Codefresh service using command line interface.
codefresh CLI tool from codefresh-io/cli.
On macOS, it’s possible to install
codefresh CLI tool from our Homebrew tap:
$ brew tap codefresh-io/cli
$ brew install codefresh
Trigger type represents new events that can trigger Codefresh pipeline execution. It can generate events (like
cron) or can be connected to an external service to generate events from it. This can be done using
To list all available trigger types, installed on Codefresh, use
codefresh get trigger-types command.
$ codefresh get trigger-types -o yaml
It’s possible to see, that only one trigger type is currently available –
Let’s take a look at a trigger type attributes:
type – is a trigger type name;
registry (Docker registry) in our case
kind – some types may be of different “kind”. For example, there are multiple Docker registries: Docker Hub, Codefresh CFCR, Amazon ECR, Google GCR and others.
uri-template – every external event has a unique identifier; trigger type can provide a template that helps to construct such identifier
uri-regex – regular expression used to validate event unique identifier
Trigger event is an
event generated or received by a Codefresh trigger type service.
First, declare a new trigger event, you would like to receive in Codefresh.
$ codefresh create trigger-event
--type registry \
--kind dockerhub \
--secret XYZ1234 \
--value namespace=codefresh \
--value name=fortune \
Successfully created registry:dockerhub:codefresh:fortune:push trigger event.
Fore some trigger events, Codefresh can subscribe to these events on a remote system. For others, you can get detailed instruction how to configure a remote syste3m.
Run the command below, to get a detailed information about the previously generated trigger event.
$ codefresh get trigger-event -o yaml registry:dockerhub:codefresh:fortune:push
description: Docker Hub codefresh/fortune push event
Docker Hub webhooks fire when an image is built in, pushed or a new tag is
added to, your repository.
Configure Docker Hub webhooks on
Add following Codefresh Docker Hub webhook endpoint
Docker Hub webhooks
Docker Hub webhooks are fired when an image is built, pushed or a new tag is
To configure Docker Hub webhooks on https://hub.docker.com/r/codefresh/fortune/~/settings/webhooks/ add the following Codefresh Docker Hub webhook endpoint
For Docker Hub trigger events, it is possible to get detailed instructions on how to set up a Docker Hub webhook and copy endpoint URL, including an automatically generated webhook secret key.
Link Trigger Event to the Codefresh pipeline
First, select a Codefresh pipeline in you would like to run when a new Docker image is pushed or tagged in its Docker Hub repository.
# list Codefresh pipelines filtered by specific REPO-OWNER/REPO-NAME
$ codefresh get pipelines --repo-owner --repo-name
# copy pipeline ID for the pipeline you want to run ...
To connect the selected Codefresh pipeline to the specified Docker Hub trigger event (
registry:dockerhub:codefresh:fortune:push in our example) use the following command:
# link Docker Hub codefresh/fortune push trigger event to the specified pipeline
$ codefresh link registry:dockerhub:codefresh:fortune:push $PIPELINE_ID
Configure a Docker Hub Webhook
- Navigate to the Docker Hub image home page and then to the
Webhookssettings, or use a link from
codefresh get trigger-eventcommand output.
- Copy trigger event
endpointURL into a Webhook URL field.
Running Codefresh Pipeline
When Codefresh runs a pipeline as a result of Docker Hub trigger event, it generates several environment variables available for all the steps in the pipeline.
The original event payload is always injected as
EVENT_PAYLOAD environment variables.
Other injected variables are prefixed with
For Docker Hub trigger event, the following variables are available:
EVENT_NAME – Docker image name
EVENT_TAG – Docker image tag name
EVENT_NAMESPACE – Docker Hub namespace
EVENT_PUSHED_AT – Docker image push timestamp (RFC 3339 formatted)
EVENT_PUSHER – Docker Hub user who pushed the image
That’s all folks!
Now every time you push a new Docker image into Docker Hub, all connected Codefresh pipelines will be executed.
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