From df4866b4d47b850897e25c81f41e48dfe0c99dcf Mon Sep 17 00:00:00 2001
From: Sung Won Cho <sung@monomax.sh>
Date: Wed, 11 Sep 2019 23:45:06 +1000
Subject: [PATCH] Allow to build for a specific platform (#250)

---
 CONTRIBUTING.md          |  7 +++++-
 Makefile                 |  8 +++---
 pkg/cli/scripts/build.sh | 54 +++++++++++++++++++++++++++++-----------
 3 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6bdbd118..cfed335c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -32,8 +32,13 @@ You can build either a development version or a production version:
 # Build a development version for your platform and place it in your `PATH`.
 make debug=true build-cli
 
-# Build a production version
+# Build a production version for all platforms
 make version=v0.1.0 build-cli
+
+# Build a production version for a specific platform
+# Note: You cannot cross-compile using this method because Dnote uses CGO
+# and requires the OS specific headers.
+GOOS=[insert OS] GOARCH=[insert arch] make version=v0.1.0 build-cli
 ```
 
 ### Test
diff --git a/Makefile b/Makefile
index ede091a4..5a19a1af 100644
--- a/Makefile
+++ b/Makefile
@@ -79,7 +79,7 @@ build-web:
 
 build-server: build-web
 ifndef version
-	$(error version is required. Usage: make version=v0.1.0 build-server)
+	$(error version is required. Usage: make version=0.1.0 build-server)
 endif
 
 	@echo "==> building server"
@@ -93,7 +93,7 @@ ifeq ($(debug), true)
 else
 
 ifndef version
-	$(error version is required. Usage: make version=v0.1.0 build-cli)
+	$(error version is required. Usage: make version=0.1.0 build-cli)
 endif
 
 	@echo "==> building cli"
@@ -104,7 +104,7 @@ endif
 ## release
 release-cli: build-cli
 ifndef version
-	$(error version is required. Usage: make version=v0.1.0 release-cli)
+	$(error version is required. Usage: make version=0.1.0 release-cli)
 endif
 ifndef HUB
 	$(error please install hub)
@@ -128,7 +128,7 @@ endif
 
 release-server: build-server
 ifndef version
-	$(error version is required. Usage: make version=v0.1.0 release-server)
+	$(error version is required. Usage: make version=0.1.0 release-server)
 endif
 ifndef HUB
 	$(error please install hub)
diff --git a/pkg/cli/scripts/build.sh b/pkg/cli/scripts/build.sh
index f2946d6d..2d276d31 100755
--- a/pkg/cli/scripts/build.sh
+++ b/pkg/cli/scripts/build.sh
@@ -2,9 +2,16 @@
 #
 # build.sh compiles dnote binary for target platforms. It is resonsible for creating
 # distributable files that can be released by a human or a script.
-# use: ./scripts/build.sh 0.4.8
+#
+# It can either cross-compile for different platforms using xgo, simply target a specific
+# platform. Set GOOS and GOARCH environment variables to disable xgo and instead
+# compile for a specific platform.
+#
+# use:
+# ./scripts/build.sh 0.4.8
+# GOOS=linux GOARCH=amd64 ./scripts/build.sh 0.4.8
 
-set -eux
+set -ex
 
 version=$1
 projectDir="$GOPATH/src/github.com/dnote/dnote"
@@ -43,18 +50,33 @@ get_binary_name() {
 build() {
   platform=$1
   arch=$2
+  # native indicates if the compilation is to take place natively on the host platform
+  # if not true, use xgo with Docker to cross-compile
+  native=$3
 
   # build binary
   destDir="$outputDir/$platform-$arch"
+  ldflags="-X main.apiEndpoint=https://api.dnote.io -X main.versionTag=$version"
+  tags="fts5"
 
   mkdir -p "$destDir"
-  xgo \
-    -go "$goVersion" \
-    -ldflags "-X main.apiEndpoint=https://api.dnote.io -X main.versionTag=$version" \
-    --targets="$platform/$arch" \
-    --tags "fts5" \
-    --dest="$destDir" \
-    "$basedir"
+
+  if [ "$native" == true ]; then
+    GOOS="$platform" GOARCH="$arch" \
+      go build \
+        -ldflags "$ldflags" \
+        --tags "$tags" \
+        -o="$destDir/cli-$platform-$arch" \
+        "$basedir"
+  else
+    xgo \
+      -go "$goVersion" \
+      --targets="$platform/$arch" \
+      -ldflags "$ldflags" \
+      --tags "$tags" \
+      --dest="$destDir" \
+      "$basedir"
+  fi
 
   binaryName=$(get_binary_name "$platform")
   mv "$destDir/cli-${platform}-"* "$destDir/$binaryName"
@@ -74,9 +96,13 @@ build() {
   popd
 }
 
-# fetch tool
-go get -u github.com/karalabe/xgo
+if [ -z "$GOOS" ] && [ -z "$GOARCH" ]; then
+  # fetch tool
+  go get -u github.com/karalabe/xgo
 
-build linux amd64
-build darwin amd64
-build windows amd64
+  build linux amd64
+  build darwin amd64
+  build windows amd64
+else
+  build "$GOOS" "$GOARCH" true
+fi