Make top-level Makefile pretty and DRY

Makefile

@@ -1,4 +1,5 @@
 Q       ?= @
+SHELL   := /bin/bash
 ROOT    := $(abspath .)
 OUT_DIR := $(ROOT)/binaries2
 
@@ -8,36 +9,17 @@ all:
 $(OUT_DIR):
 	$(Q)mkdir -p $@
 
-# TODO:
-#   1. Use $(eval) to reduce duplication
+# Helper rule to run a Docker image to perform a given build.
+define DOCKER_RUN
+.PHONY: $1-$2
+$1-$2: | $$(OUT_DIR)
+	$$(Q)./run-docker.sh $1 $2 $3 $$(OUT_DIR) @
+endef
 
-.PHONY: linux-amd64
-linux-amd64: | $(OUT_DIR)
-	$(Q)docker run \
-		--rm \
-		-v $(ROOT)/make:/make \
-		-v $(OUT_DIR):/output \
-		andrewd/musl-cross \
-		/bin/bash \
-			-c "cd /make && make PLATFORM=linux ARCH=amd64 Q=$(Q) install"
+$(eval $(call DOCKER_RUN,linux,amd64,andrewd/musl-cross))
+$(eval $(call DOCKER_RUN,android,arm,andrewd/musl-cross-arm))
+$(eval $(call DOCKER_RUN,darwin,amd64,andrewd/osxcross))
 
-.PHONY: android
-android: | $(OUT_DIR)
-	$(Q)docker run \
-		--rm \
-		-v $(ROOT)/make:/make \
-		-v $(OUT_DIR):/output \
-		andrewd/musl-cross-arm \
-		/bin/bash \
-			-c "cd /make && make PLATFORM=android Q=$(Q) install"
-
-
-.PHONY: darwin-amd64
-darwin-amd64: | $(OUT_DIR)
-	$(Q)docker run \
-		--rm \
-		-v $(ROOT)/make:/make \
-		-v $(OUT_DIR):/output \
-		andrewd/osxcross \
-		/bin/bash \
-			-c "cd /make && make PLATFORM=darwin ARCH=amd64 Q=$(Q) install"
+.PHONY: clean
+clean:
+	$(Q)$(RM) -r $(OUT_DIR)

run-docker.sh

@@ -0,0 +1,81 @@
+#!/bin/bash
+
+set -e
+set -o pipefail
+#set -x
+
+PLATFORM=$1
+ARCH=$2
+IMAGE=$3
+OUT_DIR=$4
+Q=$5
+
+# Colors
+RED="\x1b[31m"
+GREEN="\x1b[32m"
+YELLOW="\x1b[33m"
+BLUE="\x1b[34m"
+RESET="\x1b[0m"
+ERASE_LINE="\x1b[2K"
+
+# Find our real path of this directory
+REALPATH=
+for bin in realpath grealpath; do
+	##echo "Testing for ${bin}..."
+	if [ -x "`which $bin`" ]; then
+		REALPATH=`which $bin`
+	fi
+done
+
+if [ -z "$REALPATH" ]; then
+	printf "${RED}ERROR:${RESET} Could not find 'realpath' binary\n"
+	exit 1
+fi
+
+ROOT=`$REALPATH .`
+
+if [ -z "$PLATFORM" ]; then
+	printf "${RED}ERROR:${RESET} No platform specified\n"
+	exit 1
+fi
+
+if [ -z "$ARCH" ]; then
+	printf "${RED}ERROR:${RESET} No architecture specified\n"
+	exit 1
+fi
+
+if [ -z "$IMAGE" ]; then
+	printf "${RED}ERROR:${RESET} No container specified\n"
+	exit 1
+fi
+
+if [ ! -d "$OUT_DIR" ]; then
+	printf "${RED}ERROR:${RESET} Output directory not given or not a directory\n"
+	printf "    $$OUT_DIR = $OUT_DIR\n"
+	exit 1
+fi
+
+
+CID=$(docker run \
+	-d \
+	--name=static-build-${PLATFORM}-${ARCH} \
+	-v ${ROOT}/make:/make \
+	-v ${OUT_DIR}:/output \
+	$IMAGE \
+	/bin/bash \
+	-c "cd /make && make PLATFORM=${PLATFORM} ARCH=${ARCH} Q=$Q install"
+)
+
+DESC=$(printf "%s/%s" "$PLATFORM" "$ARCH")
+HEADER=$(printf "  ${GREEN}%-10s${RESET} | ${BLUE}%-15s${RESET} | %s | " "DOCKER" "$DESC" "${CID:0:12}")
+
+printf "${HEADER}${YELLOW}WAIT${RESET}"
+
+EXIT_CODE=$(docker wait $CID)
+
+if [ "$EXIT_CODE" == "0" ]; then
+	docker rm $CID >/dev/null
+	printf "\r${ERASE_LINE}${HEADER}${GREEN}SUCCESS${RESET}\n"
+else
+	printf "\r${ERASE_LINE}${HEADER}${RED}ERROR (code %d)${RESET}\n" "$EXIT_CODE"
+fi