为什么 docker build 在我的复制路径前面加上临时目录？

Question

Here is the DockerFile.

FROM microsoft/aspnet:4.7
ARG source
WORKDIR /inetpub/wwwroot
COPY ${source:-obj/Docker/publish} .

And here is the error.

Error
Building a.enterpriseextservices
Service 'a.enterpriseextservices' failed to build: COPY failed: 
GetFileAttributesEx \\?\C:\Users\jesmiller-AM\AppData\Local\Temp\docker-
builder587295999\obj\Docker\publish: The system cannot find the file specified..

For more troubleshooting information, go to 
http://aka.ms/DockerToolsTroubleshooting    docker-compose  C:\Program Files 
(x86)\Microsoft Visual Studio\2017\Community\MSBuild\Sdks\Microsoft.Docker.Sdk\build\Microsoft.VisualStudio.Docker.Compose.targets  349 

I have published the project to the obj/Docker/publish folder. Here is my docker-compose file. I used the docker-compose up command from the folder where the docker-compose.yml file is located.

version: '3'

services:
  a.web.familyconnection:
    image: a.web.familyconnection
    build:
      context: .\FamilyConnection
      dockerfile: Dockerfile
  b.enterpriseextservices:
    image: b.enterpriseextservices
    build:
      context: .\Framework\b.EnterpriseExtServices
      dockerfile: Dockerfile

Answer 1

I had the same issue. Turned out I made a silly mistake. I added the following to my .dockerignore file, just out of habit when setting up a new project:

bin
obj
.vs
.git

Then I tried running this in my Dockerfile

COPY ./bin/publish/ .

Docker gave the strange tmp path error, because it was falling back to that path since I told it to ignore my /bin folder. Once I copied to a different publish path (not bin), the problem went away.

Answer 2

It looks like your path to the folders, or where you've published your code at may be incorrect. The project should be published in the obj/Docker/publish folder inside of the respective folders defined by context

Using an example docker-compose.yml :

version: "3"

services:
  foo:
    build: ./foo
  bar:
    build: ./bar

And Dockerfile :

FROM jaydorsey/ruby-2.4.1

COPY ${source:-obj/Docker/publish} .

And a tree structure like this:

.
├── Dockerfile
├── bar
│   └── Dockerfile
├── docker-compose.yml
├── foo
│   └── Dockerfile
└── obj
    └── Docker
        └── publish

When I run docker-compose build I get the following error

Building foo
Step 1/2 : FROM jaydorsey/ruby-2.4.1
 ---> b79899b232f6
Step 2/2 : COPY ${source:-obj/Docker/publish} .
ERROR: Service 'foo' failed to build: COPY failed: stat /var/lib/docker/tmp/docker-builder186649811/obj/Docker/publish: no such file or directory

This isn't identical to yours, since I'm running macOS, but very similar. You'll note the temporary file location (which is an internal Docker artifact of how it's copying files around) and the similarity in the docker-build<randomstring> path

However, if I create the obj/Docker/publish folders underneath each respective subfolder ( context ), the docker-compose build command works fine.

.
├── Dockerfile
├── bar
│   ├── Dockerfile
│   └── obj
│       └── Docker
│           └── publish
├── docker-compose.yml
├── foo
│   ├── Dockerfile
│   └── obj
│       └── Docker
│           └── publish
└── obj
    └── Docker
        └── publish

Please check that the folder you've published exists under the contexts as noted, and not in the root.

I still believe this is a path issue as noted in the error message. I hope this provides some context that helps you debug the root cause.

Can you please confirm your file & folder layout? I'm fairly certain it's path related because of the error message. I haven't done any Docker for Windows work either but I'd also double-check your default path using the correct slash (forward vs backward)