Pre-Build/Post-Build Stages

The CI pipeline includes Pre and Post-build steps to validate and introduce checkpoints in the build process. The pre/post plugins allow you to execute some standard tasks, such as Code analysis, Load testing, Security scanning etc. You can build custom pre-build/post-build tasks or select one of the standard preset plugins provided by Devtron.

Preset plugin is an API resource which you can add within the CI build environment. By integrating the preset plugin in your application, it helps your development cycle to keep track of finding bugs, code duplication, code complexity, load testing, security scanning etc. You can analyze your code easily.

Devtron CI pipeline includes the following build stages:
Pre-Build Stage: The tasks in this stage run before the image is built.
Build Stage: In this stage, the build is triggered from the source code (container image) that you provide.
Post-Build Stage: The tasks in this stage are triggered once the build is complete.

Before you begin

Make sure you have CI build pipeline before you start configuring Pre-Build or Post-Build tasks.

Configuring Pre/Post-build Tasks

Each Pre/Post-build stage is executed as a series of events called tasks and includes custom scripts. You can create one or more tasks that are dependent on one another for execution. In other words, the output variable of one task can be used as an input for the next task to build a CI runner. The tasks will run following the execution order.

The tasks can be re-arranged by drag-and-drop; however, the order of passing the variables must be followed.

You can create a task either by selecting one of the available preset plugins or by creating a custom script.

Stage

Task

Creating Pre/Post-build Tasks

Lets take Codacy as an example and configure it in the Pre-Build stage in the CI pipeline for finding bugs, detecting dependency vulnerabilities, and enforcing code standards.

Go to the Applications and select your application from the Devtron Apps tabs.

Go to the App Configuration tab, click Workflow Editor.

Select the build pipeline for configuring the pre/post-build tasks.
On the Edit build pipeline, in the Pre-Build Stage, click + Add task.

Select Codacy from PRESET PLUGINS.
Enter a relevant name or codacy in the Task name field. It is a mandatory field.
Enter a descriptive message for the task in the Description field. It is an optional field. Note: The description is available by default.
In the Input Variables, provide the information in the following fields:

In Trigger/Skip Condition, set the trigger conditions to execute a task or Set skip conditions. As an example: CodacyEndpoint equal to https://app.codacy.com. Note: You can set more than one condition.
In Pass/Failure Condition set the conditions to execute pass or fail of your build. As an example: Pass if number of issues equal to zero. Note: You can set more than one condition.
Click Update Pipeline.
Go to the Build & Deploy, click the build pipeline and start your build.
Click Details on the build pipeline and you can view the details on the Logs.

Execute custom script

On the Edit build pipeline screen, select the Pre-build stage.
Select + Add task.
Select Execute custom script.

The task type of the custom script may be a Shell or a Container image.

Custom script - Shell

Select the Task type as Shell.

Consider an example that creates a Shell task to stop the build if the database name is not "mysql". The script takes 2 input variables, one is a global variable (DOCKER_IMAGE), and the other is a custom variable (DB_NAME) with a value "mysql". The task triggers only if the database name matches "mysql". If the trigger condition fails, this Pre-build task will be skipped and the build process will start. The variable DB_NAME is declared as an output variable that will be available as an input variable for the next task. The task fails if DB_NAME is not equal to "mysql".