I am in the process of trying out go modules in a package oriented design fashion as described here so that multiple executable services can be 'dockerized' but I am struggling to get things wired up properly in a single repo. I am unable to get successful docker image built using this approach. Most of the examples online are geared towards single module approach where main.go is and dockerfile are in the root folder.
My directory structure looks like this project1 - api - build - service1 - dockerfile - service2 - dockerfile - cmd - service1 - main.go - service2 - main.go - deployments - docs - internal - third_party - go.mod - go.sum - Makefile - vendor
# Accept the Go version for the image to be set as a build argument.
# Default to Go 1.11
ARG GO_VERSION=1.11
# First stage: build the executable.
FROM golang:${GO_VERSION}-alpine AS builder
# Create the user and group files that will be used in the running container to
# run the process as an unprivileged user.
RUN mkdir /user && \
echo 'nobody:x:65534:65534:nobody:/:' > /user/passwd && \
echo 'nobody:x:65534:' > /user/group
# Install the Certificate-Authority certificates for the service1 to be able to make
# calls to HTTPS endpoints.
RUN apk add --no-cache ca-certificates
# Set the environment variables for the go command:
# * CGO_ENABLED=0 to build a statically-linked executable
# * GOFLAGS=-mod=vendor to force `go build` to look into the `/vendor` folder.
ENV CGO_ENABLED=0 GOFLAGS=-mod=vendor
# Set the working directory outside $GOPATH to enable the support for modules.
WORKDIR /src
# Import the code from the context.
COPY ./ ./
# Build the executable to `/service1`. Mark the build as statically linked.
RUN go build \
-installsuffix 'static' \
-o /service1 .
# Final stage: the running container.
FROM scratch AS final
# Import the user and group files from the first stage.
COPY --from=builder /user/group /user/passwd /etc/
# Import the Certificate-Authority certificates for enabling HTTPS.
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
# Import the compiled executable from the second stage.
COPY --from=builder /service1 /service1
EXPOSE 8080
# # Run the compiled binary.
ENTRYPOINT ["/service1"]
When I run a docker build -t service1:v0.0.1 . I get this error for all my dependencies
/go/src/github.com/.../project1/internal/pkg/common (from $GOPATH)
main.go:15:2: cannot find package "github.com/.../project1/internal/pkg/delegates" in any of:
/usr/local/go/src/github.com/.../project1/internal/pkg/delegates (from $GOROOT)
/go/src/github.com/.../project1/internal/pkg/delegates (from $GOPATH)
main.go:16:2: cannot find package "github.com/.../project1/internal/pkg/secure" in any of:
/usr/local/go/src/github.com/.../project1/internal/pkg/secure (from $GOROOT)
/go/src/github.com/.../project1/internal/pkg/secure (from $GOPATH)
main.go:17:2: cannot find package "github.com/.../project1/statik" in any of:
/usr/local/go/src/github.com/.../project1/statik (from $GOROOT)
/go/src/github.com/.../project1/statik (from $GOPATH)
main.go:18:2: cannot find package "github.com/grpc-ecosystem/grpc-gateway/runtime" in any of:
/usr/local/go/src/github.com/grpc-ecosystem/grpc-gateway/runtime (from $GOROOT)
/go/src/github.com/grpc-ecosystem/grpc-gateway/runtime (from $GOPATH)
main.go:19:2: cannot find package "github.com/heptiolabs/healthcheck" in any of:
/usr/local/go/src/github.com/heptiolabs/healthcheck (from $GOROOT)
/go/src/github.com/heptiolabs/healthcheck (from $GOPATH)
main.go:21:2: cannot find package "github.com/rakyll/statik/fs" in any of:
/usr/local/go/src/github.com/rakyll/statik/fs (from $GOROOT)
/go/src/github.com/rakyll/statik/fs (from $GOPATH)
main.go:22:2: cannot find package "github.com/sirupsen/logrus" in any of:
/usr/local/go/src/github.com/sirupsen/logrus (from $GOROOT)
/go/src/github.com/sirupsen/logrus (from $GOPATH)
main.go:23:2: cannot find package "google.golang.org/grpc" in any of:
/usr/local/go/src/google.golang.org/grpc (from $GOROOT)
/go/src/google.golang.org/grpc (from $GOPATH)
Basically it cannot find all dependencies ...
This looks like you are building the project without experimental modules enabled while out of GOPATH.
Try copying your sources into /go/src/github.com/your-name/project1 and build the project there.
The fact that the error message refers to GOPATH indicates that the go command is not running in module mode.
The most likely causes of that are a missing go.mod file or a working directory inside $GOPATH/src. (I notice that you're explicitly changing the working directory to /src, but if $GOPATH is equal to / that's still not going to activate module mode.)
Try adding GO111MODULE=on to the environment. (That should at least resolve the immediate problem, but may expose some new ones.)