The Art of Iteration: Starting the Cycle

Greetings my fellow Technology Advocates and Specialists.

This is the Chapter #1 of my Mastering Loops in Azure DevOps Series.

In this Session, I will walk you through The Art of Iteration: Starting the Cycle.

This is a quick start guide to introduce the topic and how it is relevant to the real world.

IMPORTANT NOTE:-

The YAML Pipeline is tested on WINDOWS BUILD AGENT Only!!!

REQUIREMENTS:-

1. Azure Subscription.
2. Azure DevOps Organisation and Project.
3. Service Principal with Required RBAC (Contributor) applied on Subscription or Resource Group(s).
4. Azure Resource Manager Service Connection in Azure DevOps.

CODE REPOSITORY:-

arindam0310018 / 03-Jan-2025-DevOps__Mastering-Loops-in-Azure-DevOps

MASTERING LOOPS IN AZURE DEVOPS

Mastering Loops in Azure DevOps:-

Greetings to my fellow Technology Advocates and Specialists.

This is "Mastering Loops in Azure DevOps" Series !

DATE	TOPICS	CONTENT
03.01.2025	The Art of Iteration: Starting the Cycle	https://dev.to/arindam0310018/the-art-of-iteration-starting-the-cycle-1op
04.01.2025	The Art of Iteration: Loop in Pipeline Stage	https://dev.to/arindam0310018/the-art-of-iteration-loop-in-pipeline-stage-40he

View on GitHub

REFERENCE LINKS:-
1. Microsoft Learn - Azure Devops - Expressions.

HOW DOES MY CODE PLACEHOLDER LOOKS LIKE:-:-

MILLION DOLLAR QUESTION:-
Question: Can we use "Loop" in Azure Devops YAML Pipeline ?
Answer: YES

HOW ?
Concise summary follows below:-
1.) We can use "Loop" in Azure Devops YAML Pipeline by using the "each" keyword.
2.) We can use the "each" keyword to loop through a) Parameters with the type as b) Object.
3.) Additionally, you can iterate through Nested elements within an Object.

EXAMPLE:-

PIPELINE CODE SNIPPET:-

AZURE DEVOPS YAML PIPELINE (azure-pipelines-Leverage-Loops-For-Automation-Initial-Test.yml):-

trigger:
  none

######################
#DECLARE PARAMETERS:-
######################
parameters:
- name: RGNAME
  displayName: Please Provide the Resource Group Name:-
  type: object
  default: [AMRG001,AMRG002,AMRG003]

######################
#DECLARE VARIABLES:-
######################
variables:
  BuildAgent: windows-latest

#########################
# Declare Build Agents:-
#########################
pool:
  vmImage: $(BuildAgent)

###################
# Declare Stages:-
###################
stages:
  - ${{ each rg in parameters.RGNAME }}:
    - stage: CREATE_${{ rg }}
      jobs:
        - job: CreateResourceGroup
          steps:
            - script: echo "Creating "${{ rg }}""

EXPLANATION:-

I.) Declare "Parameter" of type "Object". In this example, I have declared 3 values (Resource Group Names) as an array.

######################
#DECLARE PARAMETERS:-
######################
parameters:
- name: RGNAME
  displayName: Please Provide the Resource Group Name:-
  type: object
  default: [AMRG001,AMRG002,AMRG003]

II.) Declare "Each" at beginning of the Pipeline stage. The "rg" variable stores all the values that the "each" keyword iterates over in the parameter of type object.

stages:
  - ${{ each rg in parameters.RGNAME }}:

III.) As there are 3 values declared in "Parameter" of type "Object", there will be 3 STAGES CREATED.

IV.) Name of each stage will be one of iterated value from the array declared in "Parameter" of type "Object".

- stage: CREATE_${{ rg }}

V.) Finally, each stage displays the Value in the console.

steps:
            - script: echo "Creating "${{ rg }}""

OUTPUT OF EXAMPLE:-
1. As in the example, there were 3 values declared in "Parameter" of type "Object", hence 3 STAGES got created.
2. Name of each stage is the iterated value from the array declared in "Parameter" of type "Object".
3. Each stage displays the Value in the console.
STAGE #1: CREATE_AMRG001
STAGE #2: CREATE_AMRG002
STAGE #3: CREATE_AMRG003

Hope You Enjoyed the Session!!!

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