Added autodetect of terrafrom project version constrains

Author: dm3ch

cmd/flora/flora.go

@@ -46,23 +46,32 @@ func main() {
 			ArgsUsage:    "TERRAFORM_VERSION",
 			BashComplete: flora.VersionsCompletion,
 			Action: func(c *cli.Context) error {
-				if c.NArg() == 0 {
-					cli.ShowSubcommandHelp(c)
+				versionConstraint := c.Args().First()
 
-					return nil
+				if versionConstraint == "" {
+					versionConstraint = flora.GetVersionConstraint()
+					
+					if versionConstraint == "" {
+						cli.ShowSubcommandHelp(c)
+						return nil
+					}
 				}
 
-				version := c.Args().First()
+				versionStr := flora.GetLatestVersionMatchingConstraint(versionConstraint)
+				if versionStr == "" {
+					log.Printf("Can't find version matching constraint %s\n", versionConstraint)
+					return nil
+				}
 
-				upgrader := flora.TerraformUpgrader{version}
+				upgrader := flora.TerraformUpgrader{versionStr}
 
-				log.Print("Downloading Terraform " + version)
+				log.Print("Downloading Terraform " + versionStr)
 
 				if err := upgrader.DownloadTerraform(); err != nil {
 					log.Fatal(err)
 				}
 
-				log.Print("Terraform " + version + " was succesfully downloaded")
+				log.Print("Terraform " + versionStr + " was succesfully downloaded")
 
 				return nil
 			},
@@ -73,15 +82,24 @@ func main() {
 			ArgsUsage:    "TERRAFORM_VERSION",
 			BashComplete: flora.VersionsCompletion,
 			Action: func(c *cli.Context) error {
-				version := c.Args().First()
+				versionConstraint := c.Args().First()
 
-				if version == "" {
-					cli.ShowCommandHelp(c, c.Command.Name)
-					return nil
+				if versionConstraint == "" {
+					versionConstraint = flora.GetVersionConstraint()
+					
+					if versionConstraint == "" {
+						cli.ShowCommandHelp(c, c.Command.Name)
+						return nil
+					}
 				}
 
-				upgrader := flora.TerraformUpgrader{version}
+				versionStr := flora.GetLatestVersionMatchingConstraint(versionConstraint)
+				if versionStr == "" {
+					log.Printf("Can't find version matching constarint %s\n", versionConstraint)
+					return nil
+				}
 
+				upgrader := flora.TerraformUpgrader{versionStr}
 				upgrader.Run()
 
 				return nil

go.mod

@@ -1,10 +1,9 @@
-module github.com/ketchup/flora
+module github.com/ketchoop/flora
 
 go 1.12
 
 require (
-	github.com/hashicorp/go-version v0.0.0-20171129150820-4fe82ae3040f
-	github.com/ketchoop/flora v0.0.0-20180403072033-15eef771532a
-	github.com/mitchellh/go-homedir v0.0.0-20161203194507-b8bc1bf76747
+	github.com/hashicorp/go-version v1.2.0
+	github.com/mitchellh/go-homedir v1.1.0
 	github.com/urfave/cli v1.20.0
 )

go.sum

@@ -1,8 +1,6 @@
-github.com/hashicorp/go-version v0.0.0-20171129150820-4fe82ae3040f h1:QnRipjW3Mm+sgD+vyO87cb+1RLzoM0mGVTYClil7mQg=
-github.com/hashicorp/go-version v0.0.0-20171129150820-4fe82ae3040f/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
-github.com/ketchoop/flora v0.0.0-20180403072033-15eef771532a h1:AUFDbm3xjeE0/oFTecZS/mHREcMp8FDnJ16YbtwtpME=
-github.com/ketchoop/flora v0.0.0-20180403072033-15eef771532a/go.mod h1:ke1QoAHYMr6+WOlnHQ2YrAWGLLVMIY1J3AexVrkwFz4=
-github.com/mitchellh/go-homedir v0.0.0-20161203194507-b8bc1bf76747 h1:eQox4Rh4ewJF+mqYPxCkmBAirRnPaHEB26UkNuPyjlk=
-github.com/mitchellh/go-homedir v0.0.0-20161203194507-b8bc1bf76747/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
+github.com/hashicorp/go-version v1.2.0 h1:3vNe/fWF5CBgRIguda1meWhsZHy3m8gCJ5wx+dIzX/E=
+github.com/hashicorp/go-version v1.2.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
+github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
+github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/urfave/cli v1.20.0 h1:fDqGv3UG/4jbVl/QkFwEdddtEDjh/5Ov6X+0B/3bPaw=
 github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=

versions.go

@@ -8,6 +8,8 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"regexp"
+	"bufio"
 
 	version "github.com/hashicorp/go-version"
 )
@@ -107,3 +109,58 @@ func ListRemoteVersions() ([]*version.Version, error) {
 
 	return versions, nil
 }
+
+func getVersionConstraintFromFile(file string) string {
+	f, err := os.Open(file)
+
+	if err != nil {
+		return ""
+	}
+	defer f.Close()
+	
+	re := regexp.MustCompile(`required_version[ \t]*=[ \t]*"(.*)"`)
+
+	scanner := bufio.NewScanner(f)
+	
+	for scanner.Scan() {
+		str := scanner.Text()
+		result := re.FindStringSubmatch(str)
+		if len(result) >= 2 && result[1] != "" {
+			return result[1]
+		}
+	}
+	
+	return ""
+}
+
+func GetVersionConstraint() string {
+	tfFiles, _ := filepath.Glob("*.tf")
+	for _, file := range tfFiles {
+		versionConstrains := getVersionConstraintFromFile(file)
+		if versionConstrains != "" {
+			return versionConstrains
+		}
+	}
+
+	return ""
+}
+
+func getVersionMatchingConstraint(constraintString string, versions []*version.Version) (*version.Version) {
+	constraint, _ := version.NewConstraint(constraintString)
+	for i := len(versions) - 1; i >= 0; i-- {
+		if constraint.Check(versions[i]) {
+			return versions[i]
+		}
+	}
+	return nil
+}
+
+func GetLatestVersionMatchingConstraint(versionConstraint string) string {
+	versions, _ := ListRemoteVersions()
+	version := getVersionMatchingConstraint(versionConstraint, versions)
+	if version == nil {
+		return ""
+	}
+
+	return version.String()
+}