Cannot build with go modules

[lapwat]

My actions before raising this issue

• Followed the troubleshooting guide
• Read/searched the docs
• Searched past issues

I would like to use go modules in my openfaas function.

Expected Behaviour

I whould be able to build my function by enabling GO111MODULE.

Current Behaviour

Building fail with this error:

handler.go:8:2: no required module provides package golang.org/x/example/stringutil; to add it:
        go get golang.org/x/example/stringutil

Steps to Reproduce (for bugs)

We are going to build a function with "golang.org/x/example/stringutil" module

1. faas new --lang=golang-middleware test-module
2. Edit test-module/handler.go

package function

import (
	"fmt"
	"io/ioutil"
	"net/http"

	"golang.org/x/example/stringutil"
)

func Handle(w http.ResponseWriter, r *http.Request) {
	var input []byte

	if r.Body != nil {
		defer r.Body.Close()

		body, _ := ioutil.ReadAll(r.Body)

		input = body
	}

	w.WriteHeader(http.StatusOK)
	w.Write([]byte(stringutil.Reverse("!selpmaxe oG ,olleH")))
}

4. faas-cli build -f test-module.yml

Step 21/36 : RUN GOOS=${TARGETOS} GOARCH=${TARGETARCH} go test ./... -cover
 ---> Running in e673616d5614
handler.go:8:2: no required module provides package golang.org/x/example/stringutil; to add it:
        go get golang.org/x/example/stringutil
The command '/bin/sh -c GOOS=${TARGETOS} GOARCH=${TARGETARCH} go test ./... -cover' returned a non-zero code: 1

Context

Pulled latest golang-middleware template.

GO111MODULE is now enabled by default.

I tried with build-args option on the cli and in test-module.yml without success.

Your Environment

• FaaS-CLI version ( Full output from: faas-cli version ):

CLI:
commit: 72816d486cf76c3089b915dfb0b66b85cf096634
version: 0.13.13

• Docker version docker version (e.g. Docker 17.0.05 ): 20.10.12

• Are you using Docker Swarm or Kubernetes (FaaS-netes)? Irrelevant

• Operating System and version (e.g. Linux, Windows, MacOS): Linux

• Code example or link to GitHub repo or gist to reproduce problem: Irrelevant

• Other diagnostic information / logs from troubleshooting guide

Next steps

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[alexellis]

@lapwat my guess is that you haven't read the docs for this, you should be setting --build-arg GO111MODULE=on

https://docs.openfaas.com/cli/templates/

We also cover this extensively in my eBook on OpenFaaS and Go -> https://gumroad.com/l/everyday-golang

[alexellis]

/add label: support,question

[lapwat]

I guess that this option is now enabled by default: #63

I also said in the context that I have tried both options:

• faas-cli build -f test-module.yml --build-arg GO111MODULE=on
• setting GO111MODULE=on in the yml file

What did I miss ?

[lapwat]

Can we reopen the issue ?

[welteki]

Judging by the error you get, your function is not a go module.

As mentioned in the docs you should run go mod init function to initialize your function and than use go get to manage your dependencies.

[lapwat]

I think that this process of 'go getting' packages is handled by the Dockerfile.

Note that I don't have this error when using the original go template.

[lapwat]

I have succeeded to build the image in this issue. I had to go mod init function and go get inside the handler folder like you advised.

I do not have to type those commands when working with the go template which was misleading.