Add cross-compilation Makefile targets and tar-based releases.

Revamp the build system to be more inline with other Prometheus exporters.
Notably add Darwin and Windows build targets, and add support for releases
using tar files.

.gitignore

@@ -9,5 +9,7 @@ postgres_exporter_integration_test
 cover.out
 cover.*.out
 .coverage
+bin
+release
 *.prom
 .metrics.*.*.prom

.travis.yml

@@ -18,6 +18,7 @@ script:
 - make docker
 - make test-integration
 - make cover.out
+- make release
 - $HOME/gopath/bin/goveralls -coverprofile=cover.out -service=travis-ci
 after_success:
 - docker login -e $DOCKER_EMAIL -u $DOCKER_USER -p $DOCKER_PASS
@@ -38,7 +39,8 @@ deploy:
   provider: releases
   api_key:
     secure: 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
-  file: postgres_exporter
+  file_glob: true
+  file: release/*
   on:
     tags: true
     branch: master

Dockerfile

 FROM scratch
-COPY postgres_exporter /postgres_exporter
+ARG binary
+
+COPY $binary /postgres_exporter
 EXPOSE 9187

Makefile

 COVERDIR = .coverage
 TOOLDIR = tools
-GO_SRC := $(shell find . -name '*.go' ! -path '*/vendor/*' ! -path 'tools/*' )
-GO_DIRS := $(shell find . -type d -name '*.go' ! -path '*/vendor/*' ! -path 'tools/*' )
+BINDIR = bin
+RELEASEDIR = release
+DIRS = $(BINDIR) $(RELEASEDIR)
+
+GO_SRC := $(shell find . -name '*.go' ! -path '*/vendor/*' ! -path 'tools/*' ! -path 'bin/*' ! -path 'release/*' )
+GO_DIRS := $(shell find . -type d -name '*.go' ! -path '*/vendor/*' ! -path 'tools/*' ! -path 'bin/*' ! -path 'release/*' )
 GO_PKGS := $(shell go list ./... | grep -v '/vendor/')
 CONTAINER_NAME ?= wrouesnel/postgres_exporter:latest
-VERSION ?= $(shell git describe --dirty)
+BINARY := $(shell basename $(shell pwd))
+VERSION ?= $(shell git describe --dirty 2>/dev/null)
+VERSION_SHORT ?= $(shell git describe --abbrev=0 2>/dev/null)
+
+ifeq ($(VERSION),)
+VERSION := v0.0.0
+endif
+
+ifeq ($(VERSION_SHORT),)
+VERSION_SHORT := v0.0.0
+endif
+
+# By default this list is filtered down to some common platforms.
+platforms := $(subst /,-,$(shell go tool dist list | grep -e linux -e windows -e darwin | grep -e 386 -e amd64))
+PLATFORM_BINS := $(patsubst %,$(BINDIR)/%/$(BINARY),$(platforms))
+PLATFORM_DIRS := $(patsubst %,$(BINDIR)/$(BINARY)_$(VERSION_SHORT)_%,$(platforms))
+PLATFORM_TARS := $(patsubst %,$(RELEASEDIR)/$(BINARY)_$(VERSION_SHORT)_%.tar.gz,$(platforms))
+
+# These are evaluated on use, and so will have the correct values in the build
+# rule (https://vic.demuzere.be/articles/golang-makefile-crosscompile/)
+PLATFORMS_TEMP = $(subst -, ,$(subst /, ,$@))
+GOOS = $(word 2, $(PLATFORMS_TEMP))
+GOARCH = $(word 3, $(PLATFORMS_TEMP))
+
+CURRENT_PLATFORM := $(BINDIR)/$(BINARY)_$(VERSION_SHORT)_$(shell go env GOOS)-$(shell go env GOARCH)/$(BINARY)
 CONCURRENT_LINTERS ?= $(shell cat /proc/cpuinfo | grep processor | wc -l)
 LINTER_DEADLINE ?= 30s
+$(shell mkdir -p $(DIRS))
+
 export PATH := $(TOOLDIR)/bin:$(PATH)
 SHELL := env PATH=$(PATH) /bin/bash
-all: style lint test postgres_exporter
-# Cross compilation (e.g. if you are on a Mac)
-cross: docker-build docker
-# Simple go build
-postgres_exporter: $(GO_SRC)
-	CGO_ENABLED=0 go build -a -ldflags "-extldflags '-static' -X main.Version=$(VERSION)" -o postgres_exporter .
-postgres_exporter_integration_test: $(GO_SRC)
-	CGO_ENABLED=0 go test -c -tags integration \
-	    -a -ldflags "-extldflags '-static' -X main.Version=$(VERSION)" -o postgres_exporter_integration_test -cover -covermode count .
+all: style lint test binary
+
+binary: $(CURRENT_PLATFORM) $(BINARY)
+
+$(BINARY):
+	ln -sf $(BINDIR)/$(BINARY)_$(VERSION_SHORT)_$(shell go env GOOS)-$(shell go env GOARCH)/$(BINARY) $@
+$(PLATFORM_BINS): $(GO_SRC)
+	CGO_ENABLED=0 GOOS=$(GOOS) GOARCH=$(GOARCH) go build -a \
+		-ldflags "-extldflags '-static' -X main.Version=$(VERSION)" \
+		-o $(BINDIR)/$(BINARY)_$(VERSION_SHORT)_$(GOOS)-$(GOARCH)/$(BINARY) .
+$(PLATFORM_DIRS): $(PLATFORM_BINS)
+$(PLATFORM_TARS): $(RELEASEDIR)/%.tar.gz : $(BINDIR)/%
+	tar -czf $@ -C $(BINDIR) $$(basename $<)
+	
+release-bin: $(PLATFORM_BINS)
+
+release: $(PLATFORM_TARS)
 # Take a go build and turn it into a minimal container
-docker: postgres_exporter
-	docker build -t $(CONTAINER_NAME) .
+docker: $(CURRENT_PLATFORM)
+	docker build --build-arg=binary=$(CURRENT_PLATFORM) -t $(CONTAINER_NAME) .
 style: tools
 	gometalinter --disable-all --enable=gofmt --vendor
@@ -42,14 +80,12 @@ lint: tools
 fmt: tools
 	gofmt -s -w $(GO_SRC)
-run-tests: tools
-	mkdir -p $(COVERDIR)
-	rm -f $(COVERDIR)/*
+test: tools
+	@mkdir -p $(COVERDIR)
+	@rm -f $(COVERDIR)/*
 	for pkg in $(GO_PKGS) ; do \
 		go test -v -covermode count -coverprofile=$(COVERDIR)/$$(echo $$pkg | tr '/' '-').out $$pkg || exit 1 ; \
 	done
-
-test: run-tests
 	gocovmerge $(shell find $(COVERDIR) -name '*.out') > cover.test.out
 test-integration: postgres_exporter postgres_exporter_integration_test
@@ -58,24 +94,13 @@ test-integration: postgres_exporter postgres_exporter_integration_test
 cover.out: tools
 	gocovmerge cover.*.out > cover.out
-# Do a self-contained docker build - we pull the official upstream container
-# and do a self-contained build.
-docker-build:
-	docker run -v $(shell pwd):/go/src/github.com/wrouesnel/postgres_exporter \
-	    -v $(shell pwd):/real_src \
-	    -e SHELL_UID=$(shell id -u) -e SHELL_GID=$(shell id -g) \
-	    -w /go/src/github.com/wrouesnel/postgres_exporter \
-		golang:1.9-wheezy \
-		/bin/bash -c "make >&2 && chown $$SHELL_UID:$$SHELL_GID ./postgres_exporter"
-	docker build -t $(CONTAINER_NAME) .
-
-push:
-	docker push $(CONTAINER_NAME)
-
+clean:
+	[ ! -z $(BINDIR) ] && [ -e $(BINDIR) ] && find $(BINDIR) -print -delete || /bin/true
+	[ ! -z $(COVERDIR) ] && [ -e $(COVERDIR) ] && find $(COVERDIR) -print -delete || /bin/true
+	[ ! -z $(RELEASEDIR) ] && [ -e $(RELEASEDIR) ] && find $(RELEASEDIR) -print -delete || /bin/true
+	rm -f postgres_exporter postgres_exporter_integration_test
+	
 tools:
 	$(MAKE) -C $(TOOLDIR)
-
-clean:
-	rm -rf postgres_exporter postgres_exporter_integration_test $(COVERDIR)
-
-.PHONY: tools docker-build docker lint fmt test vet push cross clean
+	
+.PHONY: tools style fmt test all release binary clean

README.md

@@ -126,3 +126,11 @@ GRANT SELECT ON postgres_exporter.pg_stat_replication TO postgres_exporter;
 > ```
 > DATA_SOURCE_NAME=postgresql://postgres_exporter:password@localhost:5432/postgres?sslmode=disable
 > ```
+
+# Hacking
+
+* The build system is currently only supported for Linux-like platforms. It
+  depends on GNU Make.
+* To build a copy for your current architecture run `make binary` or just `make`
+  This will create a symlink to the just built binary in the root directory.
+* To build release tar balls run `make release`.