Improve Makefile / build process

Author: mikesimons

.gitignore

@@ -1,5 +1,6 @@
 cmd/envelope/envelope
 cmd/envelope/keyring.yaml
 cmd/envelope/test.*
+build/*
 .envrc
 vendor

.travis.yml

@@ -4,10 +4,8 @@ go:
 deploy:
   provider: releases
   api_key: "$GITHUB_AUTH"
-  file:
-  - cmd/envelope/envelope-${TRAVIS_TAG}-linux-amd64
-  - cmd/envelope/envelope-${TRAVIS_TAG}-darwin-amd64
-  - cmd/envelope/envelope-${TRAVIS_TAG}-windows-amd64
+  file_glob: true
+  file: "build/envelope-*"
   skip_cleanup: true
   on:
     tags: true

Makefile

@@ -1,17 +1,24 @@
-version=$(shell git describe --all | sed -e's/.*\///g')
+repo=github.com/mikesimons/envelope
+version=$(shell git describe --all --dirty --long | awk -F"-|/" '/^heads/ {print $$2 "@" substr($$4, 2) "!" $$5}; /^tags/ { print $$2 }')
+build_args=-ldflags "-X main.envelope_version_string=$(version)" $(repo)/cmd/envelope
 
 .PHONY: test dev-deps
 
-all: test cmd/envelope/envelope-$(version)-linux-amd64 cmd/envelope/envelope-$(version)-darwin-amd64 cmd/envelope/envelope-$(version)-windows-amd64
+all: test build
 
-cmd/envelope/envelope-$(version)-linux-amd64:
-	GOARCH=amd64 GOOS=linux cd cmd/envelope && go build -o $@
+build: build-linux build-darwin build-windows 
 
-cmd/envelope/envelope-$(version)-darwin-amd64:
-	GOARCH=amd64 GOOS=darwin cd cmd/envelope && go build -o $@
+build-linux: build/envelope-$(version)-linux-amd64
+build/envelope-$(version)-linux-amd64:
+	GOARCH=amd64 GOOS=linux go build -o $@ $(build_args)
 
-cmd/envelope/envelope-$(version)-windows-amd64:
-	GOARCH=amd64 GOOS=windows cd cmd/envelope && go build -o $@
+build-darwin: build/envelope-$(version)-darwin-amd64
+build/envelope-$(version)-darwin-amd64:
+	GOARCH=amd64 GOOS=darwin go build -o $@ $(build_args)
+
+build-windows: build/envelope-$(version)-windows-amd64
+build/envelope-$(version)-windows-amd64:
+	GOARCH=amd64 GOOS=windows go build -o $@ $(build_args)
 
 dev-deps:
 	go get github.com/Masterminds/glide

cmd/envelope/main.go

@@ -8,12 +8,13 @@ import (
 )
 
 var COLLECT_DEBUG = true
+var envelope_version_string = "dev"
 
 func main() {
 	app := cli.NewApp()
 	app.Name = "envelope"
 	app.Usage = "Envelope secrets encryption"
-	app.Version = "0.0.1"
+	app.Version = envelope_version_string
 
 	app.Flags = []cli.Flag{
 		cli.StringFlag{