From d8e22f1804fcb99fc70dfbb4f54b9de28a92ebc2 Mon Sep 17 00:00:00 2001
From: Katy Moe <katy@katy.moe>
Date: Mon, 15 Jun 2020 18:54:49 +0100
Subject: [PATCH] add terraform version -json

---
 command/version.go | 80 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 65 insertions(+), 15 deletions(-)

diff --git a/command/version.go b/command/version.go
index 2a3c1056a..321340b21 100644
--- a/command/version.go
+++ b/command/version.go
@@ -2,6 +2,7 @@ package command
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"sort"
 )
@@ -16,6 +17,13 @@ type VersionCommand struct {
 	CheckFunc         VersionCheckFunc
 }
 
+type VersionOutput struct {
+	Version            string            `json:"terraform_version"`
+	Revision           string            `json:"terraform_revision"`
+	ProviderSelections map[string]string `json:"provider_selections"`
+	Outdated           bool              `json:"terraform_outdated"`
+}
+
 // VersionCheckFunc is the callback called by the Version command to
 // check if there is a new version of Terraform.
 type VersionCheckFunc func() (VersionCheckInfo, error)
@@ -34,8 +42,17 @@ func (c *VersionCommand) Help() string {
 }
 
 func (c *VersionCommand) Run(args []string) int {
+	var outdated bool
 	var versionString bytes.Buffer
 	args = c.Meta.process(args)
+	var jsonOutput bool
+	cmdFlags := c.Meta.defaultFlagSet("version")
+	cmdFlags.BoolVar(&jsonOutput, "json", false, "json")
+	if err := cmdFlags.Parse(args); err != nil {
+		c.Ui.Error(fmt.Sprintf("Error parsing command-line flags: %s\n", err.Error()))
+		return 1
+	}
+
 	fmt.Fprintf(&versionString, "Terraform v%s", c.Version)
 	if c.VersionPrerelease != "" {
 		fmt.Fprintf(&versionString, "-%s", c.VersionPrerelease)
@@ -45,8 +62,6 @@ func (c *VersionCommand) Run(args []string) int {
 		}
 	}
 
-	c.Ui.Output(versionString.String())
-
 	// We'll also attempt to print out the selected plugin versions. We can
 	// do this only if "terraform init" was already run and thus we've committed
 	// to a specific set of plugins. If not, the plugins lock will be empty
@@ -70,31 +85,66 @@ func (c *VersionCommand) Run(args []string) int {
 			pluginVersions = append(pluginVersions, fmt.Sprintf("+ provider %s v%s", providerAddr, version))
 		}
 	}
-	if len(pluginVersions) != 0 {
-		sort.Strings(pluginVersions)
-		for _, str := range pluginVersions {
-			c.Ui.Output(str)
-		}
-	}
-
 	// If we have a version check function, then let's check for
 	// the latest version as well.
 	if c.CheckFunc != nil {
-
 		// Check the latest version
 		info, err := c.CheckFunc()
-		if err != nil {
+		if err != nil && !jsonOutput {
 			c.Ui.Error(fmt.Sprintf(
 				"\nError checking latest version: %s", err))
 		}
 		if info.Outdated {
-			c.Ui.Output(fmt.Sprintf(
-				"\nYour version of Terraform is out of date! The latest version\n"+
-					"is %s. You can update by downloading from https://www.terraform.io/downloads.html",
-				info.Latest))
+			outdated = true
+			if !jsonOutput {
+				c.Ui.Output(fmt.Sprintf(
+					"\nYour version of Terraform is out of date! The latest version\n"+
+						"is %s. You can update by downloading from https://www.terraform.io/downloads.html",
+					info.Latest))
+			}
+
 		}
 	}
 
+	if jsonOutput {
+		selectionsOutput := make(map[string]string)
+		for providerAddr, cached := range providerSelections {
+			version := cached.Version.String()
+			selectionsOutput[providerAddr.String()] = version
+		}
+
+		var versionOutput string
+		if c.VersionPrerelease != "" {
+			versionOutput = c.Version + "-" + c.VersionPrerelease
+		} else {
+			versionOutput = c.Version
+		}
+
+		output := VersionOutput{
+			Version:            versionOutput,
+			Revision:           c.Revision,
+			ProviderSelections: selectionsOutput,
+			Outdated:           outdated,
+		}
+
+		jsonOutput, err := json.MarshalIndent(output, "", "  ")
+		if err != nil {
+			c.Ui.Error(fmt.Sprintf("\nError marshalling JSON: %s", err))
+			return 1
+		}
+		c.Ui.Output(string(jsonOutput))
+		return 0
+	} else {
+		c.Ui.Output(versionString.String())
+		if len(pluginVersions) != 0 {
+			sort.Strings(pluginVersions)
+			for _, str := range pluginVersions {
+				c.Ui.Output(str)
+			}
+		}
+
+	}
+
 	return 0
 }