github.com/goreleaser/goreleaser@v1.25.1/www/docs/errors/docker-build.md (about)

     1  # Docker build failures
     2  
     3  ## `COPY failed: file not found in build context`
     4  
     5  This usually happens when trying to build the binary again from source code in
     6  the Docker image build process.
     7  
     8  The way GoReleaser works, the correct binary for the platform you're building
     9  should be already available, so you don't need to build it again and can still
    10  reuse the `Dockefile`.
    11  
    12  Another common misconception is trying to copy the binary as if the context is
    13  the repository root.
    14  It's not.
    15  It's always a new temporary build context with the artifacts you can use in
    16  its root, so you can just `COPY binaryname /bin/binaryname` and etc.
    17  
    18  Below you can find some **don'ts** as well as what you should **do**.
    19  
    20  ## `expected to find X artifacts for ids [id1 id2], found Y`
    21  
    22  The `ids` property in the Dockers configuration tells GoReleaser which build IDs
    23  to include.
    24  You need to remove IDs that don't exist and/or don't build for the architecture
    25  of the image being built.
    26  Leaving it empty is also fine if you don't need any binaries.
    27  
    28  ## `use docker --context=default buildx to switch to context "default"`
    29  
    30  The "default" context is a built-in context in "docker buildx", and it is automatically created. This context typically points to the local Docker environment and is used by default for building images. It has to be active for `goreleaser` to build images with "buildx".
    31  
    32  You can switch to the default context using `docker context use default`.
    33  
    34  This change should be persistent.
    35  
    36  ### Don't
    37  
    38  Build the binary again.
    39  
    40  ```dockerfile
    41  FROM golang AS builder
    42  WORKDIR /app
    43  COPY cmd ./cmd
    44  COPY go.mod ./
    45  COPY *.go ./
    46  RUN GOOS=linux GOARCH=amd64 go build -ldflags="-w -s" -o app .
    47  
    48  FROM scratch
    49  COPY --from=builder /app/app /app
    50  ENTRYPOINT ["/app"]
    51  ```
    52  
    53  ### Don't
    54  
    55  Copy from the `dist` directory.
    56  
    57  ```dockerfile
    58  FROM scratch
    59  COPY /dist/app_linux_amd64/app /app
    60  ENTRYPOINT ["/app"]
    61  ```
    62  
    63  ### Do
    64  
    65  Copy the clean file names from the root.
    66  
    67  ```dockerfile
    68  FROM scratch
    69  COPY app /app
    70  ENTRYPOINT ["/app"]
    71  ```
    72  
    73  !!! tip
    74  
    75      If you still want your users to be able to `docker build` without an extra
    76      step, you can have a `Dockerfile` just for GoReleaser, for example, a
    77      `goreleaser.dockerfile`.