feat: adds flag to install version from a go.mod file (#8)

* feat: install version from go.mod file

* docs: update readme

README.md

@@ -22,6 +22,7 @@
     - [See all versions including release candidates (rc)](#see-all-versions-including-release-candidates-rc)
     - [Install latest version](#install-latest-version)
     - [Install specific version](#install-specific-version)
+    - [Install from mod file](#install-from-mod-file)
     - [Delete unused versions](#delete-unused-versions)
     - [Refresh version list](#refresh-version-list)
     - [Help](#help)
@@ -142,7 +143,7 @@ Use the arrow keys to navigate: ↓ ↑ → ←
 
 ### Install latest version
 
-In order to install the latest stable version, use the `--install-latest`.
+To install the latest stable version, use the `--install-latest`.
 
 ```sh
 $ gvs --install-latest
@@ -155,7 +156,7 @@ Installing version...
 
 ### Install specific version
 
-In order to install a specific version without using the dropdown, use the `--install-version=value`.
+To install a specific version without using the dropdown, use the `--install-version=value`.
 
 ```sh
 $ gvs --install-version=1.21.3
@@ -172,6 +173,18 @@ If the `Patch` version is not specified (`--install-version=1.21`), the latest `
 
 You can also pass Release Candidates, like `1.21rc2`.
 
+### Install from mod file
+
+You can also install a version that is specified in a go.mod file. You can use the flag `--from-mod`. This will look for any `go.mod` file under the same path `gvs` was executed on the terminal.
+
+```sh
+$ gvs --from-mod
+Downloading...
+Compare Checksums...
+Unzipping...
+Installing version...
+1.21.3 version is installed!
+```
 
 ### Delete unused versions
 

cmd/gvs/main.go

@@ -16,13 +16,15 @@ import (
 	"github.com/VassilisPallas/gvs/pkg/unzip"
 	"github.com/VassilisPallas/gvs/version"
 	"github.com/manifoldco/promptui"
+	"golang.org/x/mod/modfile"
 )
 
 var (
 	refreshVersions = false
 	installLatest   = false
 	deleteUnused    = false
 	showAllVersions = false
+	fromModFile     = false
 	specificVersion = ""
 )
 
@@ -33,6 +35,7 @@ func parseFlags() {
 	set.FlagBool(&deleteUnused, "delete-unused", false, "Delete all unused versions that were installed before.")
 	set.FlagBool(&refreshVersions, "refresh-versions", false, "Fetch again go versions in case the cached ones are stale.")
 	set.FlagStr(&specificVersion, "install-version", "", "Pass the version you want to install instead of selecting from the dropdown. If you do not specify the minor or the patch version, the latest one will be selected.")
+	set.FlagBool(&fromModFile, "from-mod", false, "Install the version that will be found on the go.mod file. The go.mod file should be on the same path you run gvs. If the version in the go.mod file do not specify the minor or the patch version, the latest one will be selected.")
 
 	set.Parse()
 }
@@ -77,7 +80,47 @@ func main() {
 	}
 
 	switch {
+	case fromModFile:
+		log.Info("install version from go.mod file option selected")
+
+		buf, err := fs.ReadFile("./go.mod")
+		if err != nil {
+			log.PrintError(err.Error())
+			os.Exit(1)
+			return
+		}
+
+		f, err := modfile.Parse("go.mod", buf, nil)
+		if err != nil {
+			log.PrintError(err.Error())
+			os.Exit(1)
+			return
+		}
+
+		semver := &version.Semver{}
+		err = version.ParseSemver(f.Go.Version, semver)
+		if err != nil {
+			log.PrintError(err.Error())
+			os.Exit(1)
+			return
+		}
+
+		selectedVersion := versioner.FindVersionBasedOnSemverName(versions, semver)
+		if selectedVersion == nil {
+			log.PrintError("%s is not a valid version.", semver.GetVersion())
+			os.Exit(1)
+			return
+		}
+
+		err = versioner.Install(selectedVersion, runtime.GOOS, runtime.GOARCH)
+		if err != nil {
+			log.PrintError(err.Error())
+			os.Exit(1)
+			return
+		}
 	case specificVersion != "":
+		log.Info("install specific version option selected")
+
 		semver := &version.Semver{}
 		err := version.ParseSemver(specificVersion, semver)
 		if err != nil {
@@ -94,7 +137,6 @@ func main() {
 		}
 
 		err = versioner.Install(selectedVersion, runtime.GOOS, runtime.GOARCH)
-
 		if err != nil {
 			log.PrintError(err.Error())
 			os.Exit(1)
@@ -116,7 +158,7 @@ func main() {
 			log.PrintMessage("Nothing to delete")
 		}
 	case installLatest:
-		log.Info("installLatest option selected")
+		log.Info("install latest option selected")
 
 		selectedIndex := versioner.GetLatestVersion(versions)
 		if selectedIndex == -1 {

go.mod

@@ -12,5 +12,6 @@ require (
 	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.17 // indirect
+	golang.org/x/mod v0.13.0
 	golang.org/x/sys v0.6.0 // indirect
 )

go.sum

@@ -15,6 +15,8 @@ github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovk
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
 github.com/mattn/go-isatty v0.0.17 h1:BTarxUcIeDqL27Mc+vyvdWYSL28zpIhv3RoTdsLMPng=
 github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+golang.org/x/mod v0.13.0 h1:I/DsJXRlw/8l/0c24sM9yb0T4z9liZTduXvdAWYiysY=
+golang.org/x/mod v0.13.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=