Azure Pipelines Unhandled: No Dockerfile matching "/home/vsts/work/1/s/..." Error

Question

I want to build the dockerfile of the .net service in my repo using Azure Pipeline. The folder structure is as follows:

|-- ProjectA  
|-- |-- RepoB  
|       | -- .gitignore  
|       | -- Example.sln  
|       | -- Readme.md  
|       | -- Services  
|                 | -- ServiceC  
|                      | -- ServiceC.API  
|                           | -- Program.cs   
|                           | --     .  
|                           | --     .  
|                           | -- Dockerfile  
|                 | -- ServiceD  
|                      | -- ServiceD.API  
|                           | -- Program.cs   
|                           | --     .  
|                           | --     .  
|                           | -- Dockerfile    

When I try to build the above dockerfiles with Azure pipeline, I get the following error::

[error]Unhandled: No Dockerfile matching /home/vsts/work/1/s/Dockerfile was found.

azure-pipelines.yml content as follows:

# Docker
# Build a Docker image
# https://docs.microsoft.com/azure/devops/pipelines/languages/docker

trigger:
- test

resources:
- repo: self

variables:
  tag: '$(Build.BuildId)'

stages:
- stage: Build
  displayName: Build image
  jobs:
  - job: Build
    displayName: Build
    pool:
      vmImage: ubuntu-latest
    steps:
    - task: Docker@2
      displayName: Build an image for Lesson Service
      inputs:
        command: build
        buildContext: 'Services/ServiceC/ServiceC.API/**'
        dockerfile: 'Dockerfile'
        tags: |
          $(tag)

Can you help me solve the error? Thanks for your help.

Yaml file can be run and find the Dockerfile

Answer 1

I can reproduce the same with the folder structure and yaml:

To fix the error, you need to remove buildContext parameter, and define file path for dockerfile.

    steps:
    - bash: cat Services/ServiceC/ServiceC.API/Dockerfile
    - task: Docker@2
      displayName: Build an image for Lesson Service
      inputs:
        command: build
        dockerfile: 'Services/ServiceC/ServiceC.API/Dockerfile'
        tags: |
          $(tag)

The pipeline works then:

The buildContext is useful when you have containerRegistry defined.