We should avoid setting GO env variables

It should be enough to temporarily set GOPATH during docker image build
to install tools in a shared directory and then add that directory to
$PATH.

The defaults on linux are:
GOPATH = ~/go
GOROOT = /usr/local/go
GOMODCACHE = GOPATH[0]/pkg/mod

Author: NickeZ

Dockerfile

@@ -23,12 +23,12 @@ COPY --from=android /opt/android-sdk /opt/android-sdk
 ADD scripts/docker_install.sh /tmp/
 RUN /tmp/docker_install.sh
 
-ENV GOPATH /opt/go
-ENV GOROOT /opt/go_dist/go
-ENV PATH $GOROOT/bin:$GOPATH/bin:$PATH
+# In this path executables will be installed during docker build
+ARG SYS_GOPATH /opt/go
+ENV PATH $SYS_GOPATH/bin:/usr/local/go/bin:$PATH
 
 ADD Makefile /tmp/
-RUN make -C /tmp/ envinit
+RUN GOPATH=$SYS_GOPATH make -C /tmp/ envinit
 
 ENV PATH /opt/qt6/6.8.2/gcc_64/bin:/opt/qt6/6.8.2/gcc_64/libexec:$PATH
 

Makefile

@@ -14,8 +14,6 @@
 
 SHELL    := /bin/bash
 WEBROOT  := frontends/web
-GOPATH   ?= $(HOME)/go
-PATH     := $(PATH):$(GOPATH)/bin
 
 catch:
 	@echo "Choose a make target."

android-env.mk.inc

@@ -1,4 +1,2 @@
 export ANDROID_SDK_ROOT := /opt/android-sdk
 export ANDROID_NDK_HOME := /opt/android-sdk/ndk/21.2.6472646
-# gomodcache location for gomobile build pkgs. Set to tmp folder, because writing access is needed.
-export GOMODCACHE_ROOT := /tmp/gomodcache/pkg/mod

backend/mobileserver/Makefile

@@ -1,10 +1,9 @@
 include ../../android-env.mk.inc
 
-# GOMODCACHE to /tmp directory, because gomobile needs to write pkgs.
-# Also set -glflags to fix the vendor issue with gomobile, see: https://github.com/golang/go/issues/67927#issuecomment-2241523694
+# Set -glflags to fix the vendor issue with gomobile, see: https://github.com/golang/go/issues/67927#issuecomment-2241523694
 build-android:
-	GOMODCACHE=${GOMODCACHE_ROOT} ANDROID_HOME=${ANDROID_SDK_ROOT} gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w" -target android .
+	ANDROID_HOME=${ANDROID_SDK_ROOT} gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w" -target android .
 build-ios:
-	GOMODCACHE=${GOMODCACHE_ROOT} gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w" -target ios,iossimulator .
+	gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w" -target ios,iossimulator .
 clean:
 	rm -f mobileserver.aar mobileserver-sources.jar

scripts/docker_install.sh

@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-
 apt-get update
 apt-get install -y --no-install-recommends curl ca-certificates
 
@@ -83,8 +82,7 @@ aqt install-qt linux desktop 6.8.2 -m qtpositioning qtserialport qtwebchannel qt
 npm install -g npm@10
 npm install -g locize-cli
 
-mkdir -p /opt/go_dist
-curl https://dl.google.com/go/go1.22.5.linux-amd64.tar.gz | tar -xz -C /opt/go_dist
+curl https://dl.google.com/go/go1.22.5.linux-amd64.tar.gz | tar -xz -C /usr/local
 
 # fuse is needed to run the linuxdeployqt appimage.
 apt-get install -y --no-install-recommends fuse