Add binaries build to Makefile and pipeline

Adding a stage to build prometheus exporter binaries for the
supported platforms: Linux (i386 and amd64)
Adding a clean target to remove all created artifacts if necessary

Author: ismael_serrano

Makefile

@@ -3,11 +3,41 @@ PREFIX = nginx-prometheus-exporter
 TAG = $(VERSION)
 GIT_COMMIT = $(shell git rev-parse --short HEAD)
 
+BUILD_DIR = build_output
+
+nginx-prometheus-exporter: test
+	CGO_ENABLED=0 go build -installsuffix cgo -ldflags "-X main.version=$(VERSION) -X main.gitCommit=$(GIT_COMMIT)" -o nginx-prometheus-exporter 
+
 test:
 	go test ./...
 
 container:
 	docker build --build-arg VERSION=$(VERSION) --build-arg GIT_COMMIT=$(GIT_COMMIT) -t $(PREFIX):$(TAG) . 
 
 push: container
-	docker push $(PREFIX):$(TAG)
+	docker push $(PREFIX):$(TAG)
+
+$(BUILD_DIR)/nginx-prometheus-exporter-linux-amd64:
+	GOARCH=amd64 CGO_ENABLED=0 GOOS=linux go build -installsuffix cgo -ldflags "-X main.version=$(VERSION) -X main.gitCommit=$(GIT_COMMIT)" -o $(BUILD_DIR)/nginx-prometheus-exporter-linux-amd64
+
+$(BUILD_DIR)/nginx-prometheus-exporter-linux-i386:
+	GOARCH=386 CGO_ENABLED=0 GOOS=linux go build -installsuffix cgo -ldflags "-X main.version=$(VERSION) -X main.gitCommit=$(GIT_COMMIT)" -o $(BUILD_DIR)/nginx-prometheus-exporter-linux-i386
+
+release: $(BUILD_DIR)/nginx-prometheus-exporter-linux-amd64 $(BUILD_DIR)/nginx-prometheus-exporter-linux-i386
+	mv $(BUILD_DIR)/nginx-prometheus-exporter-linux-amd64 $(BUILD_DIR)/nginx-prometheus-exporter && \
+	tar czf $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-amd64.tar.gz -C $(BUILD_DIR) nginx-prometheus-exporter && \
+	rm $(BUILD_DIR)/nginx-prometheus-exporter
+
+	mv $(BUILD_DIR)/nginx-prometheus-exporter-linux-i386 $(BUILD_DIR)/nginx-prometheus-exporter && \
+	tar czf $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-i386.tar.gz -C $(BUILD_DIR) nginx-prometheus-exporter && \
+	rm $(BUILD_DIR)/nginx-prometheus-exporter
+    
+	shasum -a 256 $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-amd64.tar.gz $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-i386.tar.gz|sed "s|$(BUILD_DIR)/||" > $(BUILD_DIR)/sha256sums.txt
+
+clean:
+	-rm $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-amd64.tar.gz
+	-rm $(BUILD_DIR)/nginx-prometheus-exporter-$(TAG)-linux-i386.tar.gz
+	-rm $(BUILD_DIR)/sha256sums.txt
+	-rmdir $(BUILD_DIR)
+	-rm nginx-prometheus-exporter
+