Bitbucket Pipelines workaround for PR target branch checks

bitbucket-pipelines.yml

# Bitbucket pipelines currently do not offer a way to specify a condition
# to only trigger jobs based on the target branch. 
# 
# See this - https://jira.atlassian.com/browse/BCLOUD-17859
#
# You need to use '**' filter to trigger the pipeline on every PR, and
# then filter for your specific branch in the pipeline
# 
# Another problem with Bitbucket pipelines is there is no ability to "reject" 
# a pipeline execution, so a manual trigger step is not very helpful as a 
# gate. But, that's a topic for another day.
# 


image: abiydv/terragrunt:1.0.9

options:
  max-time: 15

definitions: 
  scripts:
    - script: &terraform-cmd
        export TF_INPUT=0 TF_IN_AUTOMATION=1;
        terraform init -input=false; 
        terraform validate;
        terraform $TFCMD $TFCMD_OPT -input=false

  steps:
    - step: &pr-plan
        name: pr-plan
        script:
        - TFCMD="init"; TFCMD_OPT=""
        - >-
              if [ $BITBUCKET_PR_DESTINATION_BRANCH == "develop" ]; then
                cd /dev; TFCMD="plan"; TFCMD_OPT="-var-file=dev.tfvars";
              elif [ $BITBUCKET_PR_DESTINATION_BRANCH == "main" ]; then
                cd /prod; TFCMD="plan"; TFCMD_OPT="-var-file=prod.tfvars";
              else
                echo "Ignoring PR, not generating plan";
              fi
        - *terraform-cmd    
    - step: &prod-apply
        name: prod-apply
        deployment: production
        script:
        - cd /prod
        - TFCMD="apply"; TFCMD_OPT="-var-file=prod.tfvars -auto-approve"
        - *terraform-cmd
    - step: &dev-apply
        name: dev-apply
        deployment: test
        script:
        - cd /dev
        - TFCMD="apply"; TFCMD_OPT="-var-file=dev.tfvars -auto-approve"
        - *terraform-cmd

pipelines:
  branches:
    main:
      - step: *prod-apply
    develop:
      - step: *dev-apply
  pull-requests:
    '**':
      - step: *pr-plan