Pre-Build/Post-Build tasks

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, and so on. You can build custom pre/post tasks or use one from the standard preset plugins provided by Devtron.

Before you begin

Create a CI build pipeline if you haven't done that already!

Configuring Pre/Post-build stages

Each Pre/Post-build stage is executed as a series of events called tasks and includes custom scripts. You could 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 may be re-arranged by using drag-and-drop; however, the order of passing the variables must be followed.

Stage	Task
Pre-Build/Post-Build	Create a task from - Preset Plugin Sonarqube K6 Load testing Create a task from - Execute Custom script Custom script - Shell Custom script - Container image

Creating a task

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

2. From the App Configuration tab select Workflow Editor.

3. Select the build pipeline for editing the stages.

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 that you provide.

• Post-build stage: The tasks in this stage are triggered once the build is complete.

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

Preset plugins | Execute custom script

Preset plugins

Prerequisite: Set up Sonarqube, or get the API keys from an admin.

The example shows a Post-build stage with a task created using a preset plugin - Sonarqube.

1. On the Edit build pipeline screen, select the Post-build stage (or Pre-build).

2. Select + Add task.

3. Select Sonarqube from PRESET PLUGINS.

Preset plugin - Sonarqube

Field name	Required/Optional	Field description
Task name	Required	A relevant name for the task
Description	Optional	A descriptive message for the task
Input variables	Optional	VALUE: A value for the input variable. The value may be any of the values from the previous build stages, a global variable, or a custom value
Trigger/Skip Condition	Optional	A conditional statement to execute or skip the task

Input Variables

Variable	Format	Description
SonarqubeProjectKey	String	Project key of sonarqube account.
SonarqubeApiKey	String	Api key of sonarqube account.
SonarqubeEndpoint	String	Api endpoint of sonarqube account.
CheckoutPath	String	Checkout path of git material.

Select Update Pipeline.

Execute custom script

1. On the Edit build pipeline screen, select the Pre-build stage.

2. Select + Add task.

3. 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_IAMGE), 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".

Custom script - Shell

Field name	Required/Optional	Field description
Task name	Required	A relevant name for the task
Description	Optional	A descriptive message for the task
Task type	Optional	Shell: Custom shell script goes here
Input variables	Optional	Variable name: Alphanumeric chars and (_) only Source or input value: The variable's value can be global, output from the previous task, or a custom value. Accepted data types include: STRING | BOOL | NUMBER | DATE Description: Relevant message to describe the variable.
Trigger/Skip condition	Optional	A conditional statement to execute or skip the task
Script	Required	Custom script for the Pre/Post-build tasks
Output directory path		Optional
Output variables	Optional	Environment variables that are passed as input variables for the next task. Pass/Failure Condition (Optional): Conditional statements to determine the success/failure of the task. A failed condition stops the execution of the next task and/or build process

• Select Update Pipeline.

Here is a screenshot with the failure message from the task:

Pre-Build task failure

Custom script - Container image

• Select the Task type as Container image.

This example creates a Pre-build task from a container image. The output variable from the previous task is available as an input variable.

Custom script - Container image

Field name	Required/Optional	Field description
Task name	Required	A relevant name for the task
Description	Optional	A descriptive message for the task
Task type	Optional	Container image
Input variables	Optional	Variable name: Alphanumeric chars and (_) only Source or input value: The variable's value can be global, output from the previous task, or a custom value Accepted data types include: STRING | BOOL | NUMBER | DATE Description: Relevant message to describe the variable
Trigger/Skip condition	Optional	A conditional statement to execute or skip the task
Container image	Required	Select an image from the drop-down list or enter a custom value in the format <image>:<tag>
Mount custom code	Optional	Enable to mount the custom code in the container. Enter the script in the box below. Mount above code at (required): Path where the code should be mounted
Command	Optional	The command to be executed inside the container
Args	Optional	The arguments to be passed to the command mentioned in the previous field
Port mapping	Optional	The port number on which the container listens. The port number exposes the container to outside services
Mount code to container	Optional	Mounts the source code inside the container. Default is "No". If set to "Yes", enter the path
Mount directory from host	Optional	Mount any directory from the host into the container. This can be used to mount code or even output directories
Output directory path	Optional	Directory path for the script output files such as logs, errors, etc.

• Select Update Pipeline.

What's next

Trigger the CI pipeline