Add continuous deployment cookbook

docs/cookbook/2024-1-1-continous-deployment/index.md

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+---
+title: Continuous Deployment
+description: Deploy your artifacts to an app server
+slug: continuous-deployment
+authors:
+  - name: lonix1
+    url: https://github.com/lonix1
+    image_url: https://github.com/lonix1.png
+hide_table_of_contents: false
+---
+
+<!--truncate-->
+
+A typical CI pipeline contains steps such as: _clone_, _build_, _test_, _package_ and _push_. The final build product may be artifacts pushed to a git repository or a docker container pushed to a container registry.
+
+When these should be deployed on an app server, the pipeline should include a _deploy_ step, which represents the "CD" in CI/CD - the automatic deployment of a pipeline's final product.
+
+There are various ways to accomplish CD with Woodpecker, depending on your project's specific needs.
+
+## Invoking deploy script via SSH
+
+The final step in your pipeline could SSH into the app server and run a deployment script.
+
+One of the benefits would be that the deployment script's output could be included in the pipeline's log. However in general, this is a complicated option as it tightly couples the CI and app servers.
+
+An SSH step could be written by using a plugin, like [ssh](https://plugins.drone.io/plugins/ssh) or [git push](https://woodpecker-ci.org/plugins/Git%20Push).
+
+## Polling for asset changes
+
+This option completely decouples the CI and app servers, and there is no explicit deploy step in the pipeline.
+
+On the app server, one should create a script or cron job that polls for asset changes (every minute, say). When a new version is detected, the script redeploys the app.
+
+This option is easy to maintain, but the downside is a short delay (one minute) before new assets are detected.
+
+## Using a configuration management tool
+
+If you are using a configuration management tool (e.g. Ansible, Chef, Puppet), then you could setup the last pipeline step to call that tool to perform the redeployment.
+
+A plugin for [Ansible](https://woodpecker-ci.org/plugins/Ansible) exists and could be adapted accordingly.
+
+This option is complex and only suitable in an environment in which you're already using configuration management.
+
+## Using webhooks (recommended)
+
+If your forge (GitHub, GitLab, Gitea, etc.) supports webhooks, then you could create a separate listening app that receives a webhook when new assets are available and redeploys your app.
+
+The listening "app" can be something as simple as a PHP script.
+
+Alternatively, there are a number of popular webhook servers that simplify this process, so you only need to write your actual deployment script. For example, [webhook](https://github.com/adnanh/webhook) and [webhookd](https://github.com/ncarlier/webhookd).
+
+This is arguably the simplest and most maintainable solution.