feat: implement example-go service with Docker support

- Add a new Makefile with build, docker-build, test, and clean targets, including cross-compilation support for Linux AMD64 and ARM64.
- Introduce a new Go executable `example-go` with a basic HTTP server setup.
- Create a new Dockerfile for an Alpine-based container including the `example-go` binary, with metadata labels and an entrypoint.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Makefile

@@ -0,0 +1,87 @@
+EXECUTABLE ?= example-go
+SOURCES ?= $(shell find . -name "*.go" -type f)
+DIST := dist
+DIST_DIRS := $(DIST)/binaries $(DIST)/release
+GO ?= go
+TAGS ?=
+HAS_GO = $(shell hash $(GO) > /dev/null 2>&1 && echo "GO" || echo "NOGO" )
+
+ifneq ($(shell uname), Darwin)
+	EXTLDFLAGS = -extldflags "-static" $(null)
+else
+	EXTLDFLAGS =
+endif
+
+ifeq ($(HAS_GO), GO)
+	GOPATH ?= $(shell $(GO) env GOPATH)
+	export PATH := $(GOPATH)/bin:$(PATH)
+
+	CGO_EXTRA_CFLAGS := -DSQLITE_MAX_VARIABLE_NUMBER=32766
+	CGO_CFLAGS ?= $(shell $(GO) env CGO_CFLAGS) $(CGO_EXTRA_CFLAGS)
+endif
+
+ifeq ($(OS), Windows_NT)
+	GOFLAGS := -v -buildmode=exe
+	EXECUTABLE ?= $(EXECUTABLE).exe
+else ifeq ($(OS), Windows)
+	GOFLAGS := -v -buildmode=exe
+	EXECUTABLE ?= $(EXECUTABLE).exe
+else
+	GOFLAGS := -v
+	EXECUTABLE ?= $(EXECUTABLE)
+endif
+
+STORED_VERSION_FILE := VERSION
+
+ifneq ($(DRONE_TAG),)
+	VERSION ?= $(subst v,,$(DRONE_TAG))
+	RELASE_VERSION ?= $(VERSION)
+else
+	ifneq ($(DRONE_BRANCH),)
+		VERSION ?= $(subst release/v,,$(DRONE_BRANCH))
+	else
+		VERSION ?= main
+	endif
+
+	STORED_VERSION=$(shell cat $(STORED_VERSION_FILE) 2>/dev/null)
+	ifneq ($(STORED_VERSION),)
+		RELASE_VERSION ?= $(STORED_VERSION)
+	else
+		RELASE_VERSION ?= $(shell git describe --tags --always | sed 's/-/+/' | sed 's/^v//')
+	endif
+endif
+
+LDFLAGS ?= -X 'main.Version=$(RELASE_VERSION)'
+
+build: $(EXECUTABLE)
+
+$(EXECUTABLE): $(SOURCES)
+	$(GO) build -v -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o bin/$@ ./cmd/$(EXECUTABLE)
+
+docker-build: docker-build-linux-amd64 docker-build-linux-arm64
+
+docker-build-linux-amd64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 $(GO) build -v -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/amd64/$(EXECUTABLE) ./cmd/$(EXECUTABLE)
+docker-build-linux-arm64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 $(GO) build -v -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/arm64/$(EXECUTABLE) ./cmd/$(EXECUTABLE)
+
+test:
+	@$(GO) test -cover -tags '$(TAGS)' ./... && echo "\n==>\033[32m Ok\033[m\n" || exit 1
+
+# install air command
+.PHONY: air
+air:
+	@hash air > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
+		$(GO) install github.com/cosmtrek/air@latest; \
+	fi
+
+# run air
+.PHONY: dev
+dev: air
+	air --build.cmd "make build" --build.bin bin/$(EXECUTABLE)
+
+.PHONY: release-clean
+release-clean:
+	rm -rf $(DIST)
+
+clean: release-clean

cmd/example-go/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"gitea.com/action-examples/go/router"
+)
+
+func main() {
+	r := router.New()
+	// listen and serve on 0.0.0.0:8080 (for windows "localhost:8080")
+	if err := r.Run(); err != nil {
+		panic(err)
+	}
+}

docker/Dockerfile

@@ -0,0 +1,21 @@
+FROM alpine:3.19
+
+ARG TARGETOS
+ARG TARGETARCH
+
+LABEL maintainer="Bo-Yi Wu <appleboy.tw@gmail.com>" \
+  org.label-schema.name="api" \
+  org.label-schema.vendor="Bo-Yi Wu" \
+  org.label-schema.schema-version="1.0" \
+  com.centurylinklabs.watchtower.stop-signal="SIGINT" \
+  io.containers.autoupdate="registry"
+
+RUN apk update && apk add --no-cache ca-certificates
+
+EXPOSE 8080
+
+ENV GODEBUG netdns=go
+
+COPY release/${TARGETOS}/${TARGETARCH}/example-go /bin/example-go
+
+ENTRYPOINT ["/bin/example-go"]