Merge pull request #2 from envato/andrewjhumphrey-jacobsiamyversion

Merge in 99designs/iamy#63 (jacob's .iamy-version thingy)

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc // indirect
 	github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf // indirect
 	github.com/aws/aws-sdk-go v1.16.23
+	github.com/blang/semver/v4 v4.0.0
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fatih/color v1.7.0
 	github.com/ghodss/yaml v1.0.0

go.sum

@@ -4,6 +4,8 @@ github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf h1:qet1QNfXsQxTZq
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/aws/aws-sdk-go v1.16.23 h1:MwBOBeez0XEFVh6DCc888X+nHVBCjUDLnnWXSGGWUgM=
 github.com/aws/aws-sdk-go v1.16.23/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
+github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
+github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=

iamy.go

@@ -1,18 +1,29 @@
 package main
 
 import (
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
+	"reflect"
+	"regexp"
+	"strings"
 
+	"github.com/blang/semver/v4"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
+const versionTooOldError = `Your version of IAMy (%s) is out of date compared to what the local
+project expects. You should upgrade to %s to use this project.`
+const buildVersionMismatch = `Your version of IAMy (%s) does not match have the build tag the
+local project expects. You should upgrade to %s to use this project.`
+
 var (
-	Version    string = "dev"
-	defaultDir string
-	dryRun     *bool
+	Version         string = "dev"
+	defaultDir      string
+	dryRun          *bool
+	versionFileName string = ".iamy-version"
 )
 
 type logWriter struct{ *log.Logger }
@@ -61,6 +72,8 @@ func main() {
 		log.SetOutput(ioutil.Discard)
 	}
 
+	performVersionChecks()
+
 	switch cmd {
 	case push.FullCommand():
 		PushCommand(ui, PushCommandInput{
@@ -87,3 +100,36 @@ func init() {
 	}
 	defaultDir = filepath.Clean(dir)
 }
+
+func performVersionChecks() {
+	currentIAMyVersion, _ := semver.Make(strings.TrimPrefix(Version, "v"))
+	log.Printf("current versions is %s\n", currentIAMyVersion)
+
+	if _, err := os.Stat(versionFileName); !os.IsNotExist(err) {
+		log.Printf("%s found", versionFileName)
+		fileBytes, _ := ioutil.ReadFile(versionFileName)
+		fileContents := string(fileBytes)
+
+		if fileContents != "" {
+			re := regexp.MustCompile(`\d\.\d+\.\d\+?\w*`)
+			match := re.FindStringSubmatch(fileContents)
+			localDesiredVersion, _ := semver.Make(match[0])
+			log.Printf("local project wants version %s\n", localDesiredVersion)
+
+			// We don't want to notify users if the `Version` is "dev" as it's not
+			// actually too old. It could be that they are running non-released
+			// versions.
+			if Version != "dev" {
+				if currentIAMyVersion.LT(localDesiredVersion) {
+					fmt.Printf(versionTooOldError, currentIAMyVersion, localDesiredVersion)
+					os.Exit(1)
+				}
+				// Pay attention to build tags as well
+				if !reflect.DeepEqual(localDesiredVersion.Build, currentIAMyVersion.Build) {
+					fmt.Printf(buildVersionMismatch, currentIAMyVersion, localDesiredVersion)
+					os.Exit(1)
+				}
+			}
+		}
+	}
+}