From 8de69573f8efe11945c97060359ffc6ea4bbc4bf Mon Sep 17 00:00:00 2001
From: William Johansson <william.johansson@einride.tech>
Date: Mon, 1 Aug 2022 16:00:17 +0200
Subject: [PATCH] feat: format JSON output to stabilize its output

protojson doesn't guarantee stable JSON output, and deliberately
introduce minor differences in output to prevent the illusion of this,
see [1].

As this tool generates code, we'd like to keep the output as stable as
possible, use the advice in [1] and [2] (at the end) and run the
generated JSON through a formatter before including it in the generated
code. This also changes from using the error ignoring Format() function
to Marshal().

[1]: https://developers.google.com/protocol-buffers/docs/reference/go/faq#unstable-json
[2]: https://github.com/golang/protobuf/issues/1121#issuecomment-627554847
---
 cmd/protoc-gen-go-grpc-service-config/main.go | 19 +++++++++++++++----
 .../v1/example_grpc_service_config.pb.go      | 18 +++++++++---------
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/cmd/protoc-gen-go-grpc-service-config/main.go b/cmd/protoc-gen-go-grpc-service-config/main.go
index 288bd8d..829ae53 100644
--- a/cmd/protoc-gen-go-grpc-service-config/main.go
+++ b/cmd/protoc-gen-go-grpc-service-config/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -80,6 +81,19 @@ func (p *plugin) generateFromProto() error {
 		if generatedPackages[file.Desc.Package()] {
 			return fmt.Errorf("package %s has multiple default_service_config annotations", file.Desc.Package())
 		}
+
+		jsonServiceConfig, err := protojson.MarshalOptions{
+			Multiline: true,
+		}.Marshal(defaultServiceConfig)
+		if err != nil {
+			return err
+		}
+
+		var formattedServiceConfig bytes.Buffer
+		if err := json.Indent(&formattedServiceConfig, jsonServiceConfig, "", "  "); err != nil {
+			return err
+		}
+
 		generatedPackages[file.Desc.Package()] = true
 		g := p.gen.NewGeneratedFile(
 			filepath.Dir(file.GeneratedFilenamePrefix)+
@@ -92,10 +106,7 @@ func (p *plugin) generateFromProto() error {
 		g.P()
 		g.P("// DefaultServiceConfig is the default service config for all services in the package.")
 		g.P("// Source: ", file.Desc.Path(), ".")
-		g.P("const DefaultServiceConfig = `", protojson.MarshalOptions{
-			Multiline: true,
-			Indent:    "  ",
-		}.Format(defaultServiceConfig), "`")
+		g.P("const DefaultServiceConfig = `", formattedServiceConfig.String(), "`")
 	}
 	return nil
 }
diff --git a/internal/gen/proto/einride/serviceconfig/example/v1/example_grpc_service_config.pb.go b/internal/gen/proto/einride/serviceconfig/example/v1/example_grpc_service_config.pb.go
index 7421ee5..b997944 100644
--- a/internal/gen/proto/einride/serviceconfig/example/v1/example_grpc_service_config.pb.go
+++ b/internal/gen/proto/einride/serviceconfig/example/v1/example_grpc_service_config.pb.go
@@ -4,18 +4,18 @@ package examplev1
 // DefaultServiceConfig is the default service config for all services in the package.
 // Source: einride/serviceconfig/example/v1/default_service_config.proto.
 const DefaultServiceConfig = `{
-  "methodConfig":  [
+  "methodConfig": [
     {
-      "name":  [
+      "name": [
         {}
       ],
-      "timeout":  "10s",
-      "retryPolicy":  {
-        "maxAttempts":  5,
-        "initialBackoff":  "0.200s",
-        "maxBackoff":  "60s",
-        "backoffMultiplier":  2,
-        "retryableStatusCodes":  [
+      "timeout": "10s",
+      "retryPolicy": {
+        "maxAttempts": 5,
+        "initialBackoff": "0.200s",
+        "maxBackoff": "60s",
+        "backoffMultiplier": 2,
+        "retryableStatusCodes": [
           "UNAVAILABLE",
           "UNKNOWN"
         ]