Dynamically deploying services

Harness Experts
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This article helps you get the most out of the NextGen platform

Introduction

Currently, this feature is behind a Feature Flag. Contact Harness Support to enable the feature.

Looping strategies enable you to run a Stage or Step multiple times with different inputs. This eliminates the need to copy the same Stage or Step for each variation you need. It also makes the Pipeline more readable, clean, and easy to maintain.

Looping strategies enable use cases such as:

  • Deploy multiple services specifying it only in your git repository.
  • Identify changes in your git repository and run steps/stages only on changed folders.
  • You want to test a UI feature in multiple browsers and platforms. You can define a matrix that specifies the browsers and platforms to test.

Deploy multiple services dynamically

In this example, I’ll iterate through the folders of a repository I created and print its content in the next step; your use case will probably be more complex, using helm, terraform, and others to deploy.
The only requirement in this example is git installed on your delegate.

If you don’t know how to install binaries in your delegate, take a look at Install Software on the Delegate with Initialization Scripts - Harness.io Docs.

pipeline:
  name: dynamically-deploying-services
  identifier: dynamicallydeployingservices
  projectIdentifier: teste
  orgIdentifier: default
  tags: {}
  stages:
    - stage:
        name: Deploy multiple services
        identifier: Deploy_multiple_services
        description: ""
        type: Custom
        spec:
          execution:
            steps:
              - step:
                  type: ShellScript
                  name: Retrieve folder list
                  identifier: Retrieve_folder_list
                  spec:
                    shell: Bash
                    onDelegate: true
                    source:
                      type: Inline
                      spec:
                        script: |-
                          set -e

                          REPOSITORY_NAME="<+pipeline.variables.REPOSITORY_NAME>"

                          rm -rf $REPOSITORY_NAME

                          git clone https://github.com/guirociozanini/$REPOSITORY_NAME.git

                          cd $REPOSITORY_NAME

                          FOLDERS=$(ls -d */  | tr '\n' ',' | xargs echo | sed 's/ / /g')
                    environmentVariables: []
                    outputVariables:
                      - name: FOLDERS
                        type: String
                        value: FOLDERS
                  timeout: 10m
              - step:
                  type: ShellScript
                  name: Deploy service
                  identifier: Deploy_service
                  spec:
                    shell: Bash
                    onDelegate: true
                    source:
                      type: Inline
                      spec:
                        script: |-
                          cd <+pipeline.variables.REPOSITORY_NAME>/<+repeat.item>
                          ls -a
                          echo "deploying service: <+repeat.item>"
                    environmentVariables: []
                    outputVariables: []
                  timeout: 10m
                  failureStrategies: []
                  strategy:
                    repeat:
                      items: <+<+steps.Retrieve_folder_list.output.outputVariables.FOLDERS>.split(",")>
        tags: {}
  variables:
    - name: REPOSITORY_NAME
      type: String
      description: ""
      value: lab-iterate-folders-dynamically

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Notes

Conclusion

This article covers in a fundamental way, how to get the most out of the NextGen platform. If you have any suggestions on how to improve this article, or helpful and specific examples of permissions related issues that may be of use to others, please leave a comment with the information as this document is intended to evolve over time.
If this article cannot resolve your issue, don’t hesitate to contact us here: support@harness.io – or through the Zendesk portal in Harness SaaS.

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