internal/lsp/cmd: use JSON output for the inspect subcommand

I've been using the inspect command to find data about the daemon and
its various sessions while debugging gopls. In practice, however, I
don't simply want to view the debug information: I want to script it.
This change removes the custom output formatting in favor of indented
JSON, so that we can do things like the following:

  tail -f $(gopls inspect sessions | gq -r .logfile)

Which tails the daemon logs for the current gopls binary version.

Change-Id: I8895644b1493862f027e6c4b06e32612a4f3927d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/233357
Run-TryBot: Robert Findley <[email protected]>
Reviewed-by: Heschi Kreinick <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

Author: findleyr

internal/lsp/cmd/inspect.go

@@ -6,8 +6,11 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
 	"flag"
 	"fmt"
+	"log"
+	"os"
 
 	"golang.org/x/tools/internal/lsp/lsprpc"
 	"golang.org/x/tools/internal/tool"
@@ -89,18 +92,10 @@ func (c *listSessions) Run(ctx context.Context, args ...string) error {
 	if err != nil {
 		return err
 	}
-	fmt.Printf("Server logfile: %s\n", state.Logfile)
-	fmt.Printf("Server debug address: %v\n", state.DebugAddr)
-	for _, c := range state.Clients {
-		if c.ClientID == state.CurrentClientID {
-			// This is the client for the listsessions command itself.
-			continue
-		}
-		fmt.Println()
-		fmt.Printf("Client %s:\n", c.ClientID)
-		fmt.Printf("\tsession: %s:\n", c.SessionID)
-		fmt.Printf("\tlogfile: %s:\n", c.Logfile)
-		fmt.Printf("\tdebug address: %s:\n", c.DebugAddr)
+	v, err := json.MarshalIndent(state, "", "\t")
+	if err != nil {
+		log.Fatal(err)
 	}
+	os.Stdout.Write(v)
 	return nil
 }