将dependensOn设置为上一阶段，而不在Azure管道中对值进行硬编码

Question

使用Azure Pipelines，如何在不硬编码值的情况下将dependsOn设置为前一阶段？

有什么预定义的变量我可以使用吗？我只看到了当前阶段，没有看到之前的阶段。

我的管道正在执行Terraform部署。第一个(构建(阶段为每个环境并行运行terraform plan，然后由在每个环境中顺序使用计划文件运行terraform apply的(部署(阶段使用。

我在计划(构建(和应用(部署(阶段使用两个不同的模板。我目前正在使用一个参数来指定dependsOn列表值，其中我需要明确指定所有计划(构建(阶段，但对于应用(部署(阶段，我希望将参数的默认值设置为类似于$(build.PreviousStage(的值，以使其更优雅。

# azure-pipelines.yml
# LINES REMOVED #
stages:
# Terraform Plan (DevTest)
- template: templates/plan.yml
parameters:
az_service_connection: DevTest-Terraform
environment: DevTest
# Terraform Plan (Stage)
- template: templates/plan.yml
parameters:
az_service_connection: Stage-Terraform
environment: Stage
# Terraform Plan (Prod)
- template: templates/plan.yml
parameters:
az_service_connection: Prod-Terraform
environment: Prod
# Terraform Deploy (DevTest)
- template: templates/deploy.yml
parameters:
az_service_connection: DevTest-Terraform
depends_on:
- DevTest_Plan
- Stage_Plan
- Prod_Plan
environment: DevTest
# Terraform Deploy (Stage)
- template: templates/deploy.yml
parameters:
az_service_connection: Stage-Terraform
depends_on:
- DevTest_Deploy
environment: Stage
# Terraform Deploy (Prod)
- template: templates/deploy.yml
parameters:
az_service_connection: Prod-Terraform
depends_on:
- Stage_Deploy
environment: Prod

# ./templates/deploy.yml
parameters:
- name: az_service_connection
type: string
- name: depends_on
type: object
- name: environment
type: string
stages:
# Terraform Deploy
- stage: ${{ parameters.environment }}_Deploy
displayName: Terraform Deploy (${{ parameters.environment }})
condition: and(succeeded(), in(variables['Build.Reason'], 'IndividualCI', 'BatchedCI', 'Manual'))
dependsOn:
${{ parameters.depends_on }}
# LINES REMOVED #

Answer 1

一个if条件，用于检查depends_on参数是否为空，同时还将参数默认设置为"quot；允许我解决这个问题，允许我为第一个DEV部署阶段设置depends_on参数，而不为其他阶段设置。

正如@Krzysztof Madej在他的回答/评论中所说，不存在这样的变量来设置dependsOn的前一阶段，但如果不设置，则会自动依赖于前一阶段。

# azure-pipelines.yml
# LINES REMOVED #
stages:
# Terraform Plan (DevTest)
- template: templates/plan.yml
parameters:
az_service_connection: DevTest-Terraform
environment: DevTest
# Terraform Plan (Stage)
- template: templates/plan.yml
parameters:
az_service_connection: Stage-Terraform
environment: Stage
# Terraform Plan (Prod)
- template: templates/plan.yml
parameters:
az_service_connection: Prod-Terraform
environment: Prod
# Terraform Deploy (DevTest)
- template: templates/deploy.yml
parameters:
az_service_connection: DevTest-Terraform
depends_on:
- DevTest_Plan
- Stage_Plan
- Prod_Plan
environment: DevTest
# Terraform Deploy (Stage)
- template: templates/deploy.yml
parameters:
az_service_connection: Stage-Terraform
environment: Stage
# Terraform Deploy (Prod)
- template: templates/deploy.yml
parameters:
az_service_connection: Prod-Terraform
environment: Prod

# templates/deploy.yml
parameters:
- name: az_service_connection
type: string
- name: depends_on
type: object
default:
- name: environment
type: string
stages:
# Terraform Deploy
- stage: ${{ parameters.environment }}_Deploy
displayName: Terraform Deploy (${{ parameters.environment }})
condition: and(succeeded(), in(variables['Build.Reason'], 'IndividualCI', 'BatchedCI', 'Manual'))
${{ if ne(length(parameters.depends_on), 0) }}:
dependsOn:
${{ parameters.depends_on }}

Answer 2

没有像您提到的那样的变量，但

当您在管道中定义多个阶段时，默认情况下，它们按照您在YAML文件中定义它们的顺序一个接一个地运行。管道必须至少包含一个没有依赖关系的阶段。

和

# if you do not use a dependsOn keyword, stages run in the order they are defined
stages:
- stage: QA
jobs:
- job:
...
- stage: Prod
jobs:
- job:
...

正如这里所写的。所以，如果您不定义dependensOn阶段应该隐式地依赖于前一阶段。