Docker build failures¶

COPY failed: file not found in build context¶

This usually happens when trying to build the binary again from source code in the Docker image build process.

The way GoReleaser works, the correct binary for the platform you're building should be already available, so you don't need to build it again and can still reuse the Dockefile.

Another common misconception is trying to copy the binary as if the context is the repository root. It's not. It's always a new temporary build context with the artifacts you can use in its root, so you can just COPY binaryname /bin/binaryname and etc.

Below you can find some don'ts as well as what you should do.

use docker --context=default buildx to switch to context "default"¶

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".

You can switch to the default context using docker context use default.

This change should be persistent.

Don't¶

Build the binary again.

FROM golang AS builder
WORKDIR /app
COPY cmd ./cmd
COPY go.mod ./
COPY *.go ./
RUN GOOS=linux GOARCH=amd64 go build -ldflags="-w -s" -o app .

FROM scratch
COPY --from=builder /app/app /app
ENTRYPOINT ["/app"]

Don't¶

Copy from the dist folder.

FROM scratch
COPY /dist/app_linux_amd64/app /app
ENTRYPOINT ["/app"]

Do¶

Copy the clean file names from the root.

FROM scratch
COPY app /app
ENTRYPOINT ["/app"]