Clean up build stuff

1. Uses modern go in Dockerfile
2. Fix `make build` pre-reqs
3. Remove interim BUILDFLAGS handling

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

.github/workflows/test.yml

@@ -1,4 +1,4 @@
-name: Go
+name: CI
 
 on:
   push:
@@ -11,7 +11,7 @@ jobs:
     name: Build
     strategy:
       matrix:
-        go-version: [1.13.x, 1.15.x, 1.16.x, 1.17.x, 1.18.x]
+        go-version: [1.18.x, 1.19.x, 1.20.x, 1.21.x]
         platform: [ubuntu-20.04]
     runs-on: ${{ matrix.platform }}
     steps:
@@ -24,15 +24,15 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Build
-        run: go build -v ./...
+        run: make build
 
       - name: Test
-        run: go test -v ./...
+        run: make test
 
   lint:
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v4
       - uses: golangci/golangci-lint-action@v3.7.0
         with:
-          version: v1.51
+          version: v1.55

Dockerfile

@@ -1,20 +1,13 @@
-ARG GO_VERSION=1.18
-ARG GO_IMAGE=golang:${GO_VERSION}
+ARG GO_VERSION=1.21
 
-FROM --platform=$BUILDPLATFORM $GO_IMAGE AS build
+FROM golang:${GO_VERSION} AS build
 COPY . /go/src/github.com/cpuguy83/go-md2man
 WORKDIR /go/src/github.com/cpuguy83/go-md2man
-ARG TARGETOS
-ARG TARGETARCH
-ARG TARGETVARIANT
 RUN \
-    export GOOS="${TARGETOS}"; \
-    export GOARCH="${TARGETARCH}"; \
-    if [ "${TARGETARCH}" = "arm" ] && [ "${TARGETVARIANT}" ]; then \
-    export GOARM="${TARGETVARIANT#v}"; \
-    fi; \
-    CGO_ENABLED=0 go build
+    --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=cache,target=/root/.cache/go-build \
+    make build
 
 FROM scratch
-COPY --from=build /go/src/github.com/cpuguy83/go-md2man/go-md2man /go-md2man
+COPY --from=build /go/src/github.com/cpuguy83/go-md2man/bin/go-md2man /go-md2man
 ENTRYPOINT ["/go-md2man"]

Makefile

@@ -3,6 +3,36 @@ LINTER_BIN ?= golangci-lint
 
 export GO111MODULE
 
+GOOS ?= $(if $(TARGETOS),$(TARGETOS),)
+GOARCH ?= $(if $(TARGETARCH),$(TARGETARCH),)
+
+ifeq ($(TARGETARCH),amd64)
+GOAMD64 ?= $(TARGETVARIANT)
+endif
+
+ifeq ($(TARGETARCH),arm)
+GOARM ?= $(TARGETVARIANT:v%=%)
+endif
+
+ifneq ($(GOOS),)
+export GOOS
+endif
+
+ifneq ($(GOARCH),)
+export GOARCH
+endif
+
+ifneq ($(GOAMD64),)
+export GOAMD64
+endif
+
+ifneq ($(GOARM),)
+export GOARM
+endif
+
+vars:
+	@go env
+
 .PHONY:
 build: bin/go-md2man
 
@@ -14,12 +44,9 @@ clean:
 test:
 	@go test $(TEST_FLAGS) ./...
 
-bin/go-md2man: actual_build_flags := $(BUILD_FLAGS) -o bin/go-md2man
-bin/go-md2man: bin
-	@CGO_ENABLED=0 go build $(actual_build_flags)
-
-bin:
-	@mkdir ./bin
+bin/go-md2man: go.mod go.sum md2man/* *.go
+	@mkdir -p bin
+	CGO_ENABLED=0 go build $(BUILD_FLAGS) -o $@
 
 .PHONY: mod
 mod: