Provide an updated Dockerfile where Gogs is build with Go 1.8 (#4151)

In order to have an up to date Docker image based on alpine 3.5
  and having Gogs built with Go 1.8

Refs: [ #4145 ]

Dockerfile

@@ -1,5 +1,4 @@
-FROM alpine:3.3
-MAINTAINER jp@roemer.im
+FROM alpine:3.5
 
 # Install system utils & Gogs runtime dependencies
 ADD https://github.com/tianon/gosu/releases/download/1.9/gosu-amd64 /usr/sbin/gosu
@@ -8,9 +7,12 @@ RUN chmod +x /usr/sbin/gosu \
 
 ENV GOGS_CUSTOM /data/gogs
 
-COPY . /app/gogs/
-WORKDIR /app/gogs/
-RUN ./docker/build.sh
+COPY . /app/gogs/build
+WORKDIR /app/gogs/build
+
+RUN    ./docker/build-go.sh \
+    && ./docker/build.sh \
+    && ./docker/finalize.sh
 
 # Configure LibC Name Service
 COPY docker/nsswitch.conf /etc/nsswitch.conf
@@ -18,5 +20,5 @@ COPY docker/nsswitch.conf /etc/nsswitch.conf
 # Configure Docker Container
 VOLUME ["/data"]
 EXPOSE 22 3000
-ENTRYPOINT ["docker/start.sh"]
+ENTRYPOINT ["/app/gogs/docker/start.sh"]
 CMD ["/bin/s6-svscan", "/app/gogs/docker/s6/"]

docker/build-go.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+# Build GO version as specified in Dockerfile
+
+set -x
+set -e
+
+# Components versions
+export GOLANG_VERSION="1.8"
+export GOLANG_SRC_URL="https://golang.org/dl/go$GOLANG_VERSION.src.tar.gz"
+export GOLANG_SRC_SHA256="406865f587b44be7092f206d73fc1de252600b79b3cacc587b74b5ef5c623596"
+
+
+# Install build tools
+apk add --no-cache --no-progress --virtual build-deps-go gcc musl-dev openssl go
+
+export GOROOT_BOOTSTRAP="$(go env GOROOT)"
+
+# Download Go
+wget -q "$GOLANG_SRC_URL" -O golang.tar.gz
+echo "$GOLANG_SRC_SHA256  golang.tar.gz" | sha256sum -c -
+tar -C /usr/local -xzf golang.tar.gz
+rm golang.tar.gz
+
+# Build
+cd /usr/local/go/src
+# see https://golang.org/issue/14851
+patch -p2 -i /app/gogs/build/docker/no-pic.patch
+./make.bash
+
+# Clean
+rm /app/gogs/build/docker/*.patch
+apk del build-deps-go

docker/build.sh

@@ -4,16 +4,18 @@ set -e
 
 # Set temp environment vars
 export GOPATH=/tmp/go
-export PATH=${PATH}:${GOPATH}/bin
+export PATH=/usr/local/go/bin:${PATH}:${GOPATH}/bin
 export GO15VENDOREXPERIMENT=1
 
 # Install build deps
-apk --no-cache --no-progress add --virtual build-deps build-base linux-pam-dev go
+apk --no-cache --no-progress add --virtual build-deps build-base linux-pam-dev
 
 # Build Gogs
 mkdir -p ${GOPATH}/src/github.com/gogits/
-ln -s /app/gogs/ ${GOPATH}/src/github.com/gogits/gogs
+ln -s /app/gogs/build ${GOPATH}/src/github.com/gogits/gogs
 cd ${GOPATH}/src/github.com/gogits/gogs
+# Needed since git 2.9.3 or 2.9.4
+git config --global http.https://gopkg.in.followRedirects true
 go get -v -tags "sqlite cert pam" ./...
 make build TAGS="sqlite cert pam"
 

docker/finalize.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+# Finalize the build
+
+set -x
+set -e
+
+# Move to final place
+mv /app/gogs/build/gogs /app/gogs/
+mv /app/gogs/build/templates /app/gogs/
+mv /app/gogs/build/public /app/gogs/
+mv /app/gogs/build/docker /app/gogs/
+
+# Final cleaning
+rm -rf /app/gogs/build
+rm /app/gogs/docker/build.sh
+rm /app/gogs/docker/build-go.sh
+rm /app/gogs/docker/finalize.sh
+rm /app/gogs/docker/nsswitch.conf
+rm /app/gogs/docker/README.md
+
+rm -rf /tmp/go
+rm -rf /usr/local/go

docker/no-pic.patch

@@ -0,0 +1,16 @@
+diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
+index 14f4fa9..5599307 100644
+--- a/src/cmd/link/internal/ld/lib.go
++++ b/src/cmd/link/internal/ld/lib.go
+@@ -1272,6 +1272,11 @@ func hostlink() {
+ 		argv = append(argv, peimporteddlls()...)
+ 	}
+ 
++	// The Go linker does not currently support building PIE
++	// executables when using the external linker. See:
++	// https://github.com/golang/go/issues/6940
++	argv = append(argv, "-fno-PIC")
++
+ 	if l.Debugvlog != 0 {
+ 		l.Logf("%5.2f host link:", obj.Cputime())
+ 		for _, v := range argv {