Fix vendoring for golang-http

Tested with a private Go module which was vendored, setting
GO111MODULE: off in build_args in stack.yml

I also created a nested package called pkg and referenced it
as "handler/function/pkg" from handler.go which worked as
expected.

Closes: #78

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

template/golang-http/Dockerfile

@@ -22,6 +22,7 @@ ARG GOFLAGS=""
 ARG CGO_ENABLED=0
 ENV CGO_ENABLED=${CGO_ENABLED}
 
+RUN sh modules-cleanup.sh
 
 # Run a gofmt and exclude all vendored code.
 RUN test -z "$(gofmt -l $(find . -type f -name '*.go' -not -path "./vendor/*" -not -path "./function/vendor/*"))" || { echo "Run \"gofmt -s -w\" on your Golang code"; exit 1; }

template/golang-http/function/go.mod

@@ -1,3 +1,5 @@
 module handler/function
 
 go 1.18
+
+require github.com/openfaas/templates-sdk/go-http v0.0.0-20220408082716-5981c545cb03

template/golang-http/function/go.sum

@@ -0,0 +1,2 @@
+github.com/openfaas/templates-sdk/go-http v0.0.0-20220408082716-5981c545cb03 h1:wMIW4ddCuogcuXcFO77BPSMI33s3QTXqLTOHY6mLqFw=
+github.com/openfaas/templates-sdk/go-http v0.0.0-20220408082716-5981c545cb03/go.mod h1:2vlqdjIdqUjZphguuCAjoMz6QRPm2O8UT0TaAjd39S8=

template/golang-http/modules-cleanup.sh

@@ -0,0 +1,149 @@
+#!/usr/bin/env sh
+
+set -e
+
+GO111MODULE=$(go env GO111MODULE)
+
+# move_vendor will copy the function's vendor folder,
+# if it exists.
+move_vendor() {
+    if [ ! -d ./function/vendor ]; then
+        echo "vendor not found"
+        return
+    fi
+
+    echo "moving function vendor"
+    mv -f ./function/vendor .
+}
+
+
+# cleanup_gomod will move the function's go module
+cleanup_gomod() {
+
+    # Nothing to do when modules is explicitly off
+    # the z prefix protects against any SH wonkiness
+    # see https://stackoverflow.com/a/18264223
+    if [ "z$GO111MODULE" = "zoff" ]; then
+        echo "modules disabled, skipping go.mod cleanup"
+        return;
+    fi
+
+    if [ ! -f ./function/go.mod ]; then
+        echo "module not initialized, skipping go.mod cleanup"
+        return;
+    fi
+
+    echo "cleaning up go.mod"
+
+    # Copy the user's go.mod
+    mv -f ./function/go.mod .
+    mv -f ./function/go.sum .
+
+    # Clean up the go.mod
+
+    # Cleanup any sub-module replacements.
+    # This requires modifying any replace that points to "./*",
+    # the user has will use this to reference sub-modules instead
+    # of sub-packages, which we cleanup below.
+    echo "cleanup local replace statements"
+    # 1. Replace references to the local folder with `./function`
+    sed -i 's/=> \.\//=> \.\/function\//' go.mod
+
+
+    # Remove any references to the handler/function module.
+    # It is ok to just remove it because we will replace it later.
+    #
+    # Note that these references may or may not exist. We expect the
+    # go.mod to have a replace statement _if_  developer has subpackages
+    # in their handler. In this case they will need a this replace statement
+    #
+    #    replace handler/function => ./
+    #
+    # `go mod` will then add a line that looks like
+    #
+    #    handler/function v0.0.0-00010101000000-000000000000
+    #
+    # both of these lines need to be replaced, this grep selects everything
+    # _except_ those offending lines.
+    grep -v "\shandler/function" go.mod > gomod2; mv gomod2 go.mod
+
+    # Now update the go.mod
+    #
+    # 1. use replace so that imports of handler/function use the local code
+    # 2. we need to rename the module to handler because our main.go assumes
+    #    this is the package name
+    go mod edit \
+        -replace=handler/function=./function \
+        -module handler
+
+
+
+    if [ "$DEBUG" -eq 1 ]; then
+        cat go.mod
+        echo ""
+    fi
+}
+
+
+# cleanup_vendor_modulestxt will cleanup the modules.txt file in the vendor folder
+# this file is needed when modules are enabled and it must be in sync with the
+# go.mod.  To function correctly we need to modify the references to handler/function,
+# if they exist.
+cleanup_vendor_modulestxt() {
+    if [ ! -d ./vendor ]; then
+        echo "no vendor found, skipping modules.txt cleanup"
+        return
+    fi
+
+    # Nothing to do when modules is explicitly off
+    # the z prefix protects against any SH wonkiness
+    # see https://stackoverflow.com/a/18264223
+    if [ "z$GO111MODULE" = "zoff" ]; then
+        echo "modules disabled, skipping modules.txt cleanup"
+        return;
+    fi
+
+    echo "cleanup vendor/modules.txt"
+
+    # just in case
+    touch "./vendor/modules.txt"
+
+    # when vendored, we need to do similar edits to the vendor/modules.txt
+    # as we did to the go.mod
+
+    # 1. we need to replace any possible copy of the handler code
+    rm -rf vendor/handler && \
+
+    # 2. in modules.txt, we remove existing references to the handler/function
+    #    we reconstruct these in the last step
+    grep -v "\shandler/function" ./vendor/modules.txt> modulestext; mv modulestext ./vendor/modules.txt
+
+    # 3. Handle any other local replacements.
+    # any replace that points to `./**` needs to be udpat    echo "cleanup local replace statements"
+    sed -i 's/=> \.\//=> \.\/function\//' ./vendor/modules.txt
+
+    # 4. To make the modules.txt consistent with the new go.mod,
+    #    we add the mising replace to the vendor/modules.txt
+    echo "## explicit" >> ./vendor/modules.txt
+    echo "# handler/function => ./function" >> ./vendor/modules.txt
+
+    if [ "$DEBUG" -eq 1 ]; then
+        cat ./vendor/modules.txt;
+        echo ""
+    fi
+}
+
+# has_local_replacement checks if the file contains local go module replacement
+has_local_replacement() {
+    return "$(grep -E -c '=> \./\S+' "$1")"
+}
+
+
+################
+#   main
+################
+move_vendor
+
+cleanup_gomod
+
+cleanup_vendor_modulestxt