Coodiners Meetup Rosenheim, März 2023, Mario-Leander Reimer (@LeanderReimer, Principal Software Architect bei QAware). == Dokument bitte herunterladen, falls unscharf! Please download slides if blurred! == This talk focused on modern and efficient Inter Process Communication (IPC) for microservices. We start with a REST API, built using JAX-RS and Quarkus to briefly discuss the pros and cons of this approach. We extended the API with an efficient Protobuf payload representation in order to finally transform the API into a fully fledged high-performance gRPC interface definition. But that’s not all! To put some extra icing on the cake, this talk demonstrated how to consume the gRPC service from a JavaScript web client and also how to completely generate a matching REST API from an enhanced gRPC interface definition to ensure full interoperability in a microservice architecture.

1. qaware.de
REST in Peace. Long live gRPC!
Codineers Rosenheim
Mario-Leander Reimer
mario-leander.reimer@qaware.de
@LeanderReimer

2. 2
Mario-Leander Reimer
Managing Director | CTO
@LeanderReimer
#cloudnativenerd #qaware
#gernperDude

3. Agenda
QAware | 3
QAware | 3
QAware | 3
REST Beer
Service
REST Beer
Service
application/json
application/x-protobuf
gRPC Beer
Service
gRPC Beer
Service
gRPC Beer
Web UI
gRPC Beer
Client
gRPC REST
Gateway
application/json
gRPC LB
Nginx
gRPC
gRPC
gRPC
gRPC
gRPC
Web UI
gRPC Web
Envoy
TypeScript

4. Choose your framework and language
ⓘ Start presenting to display the poll results on this slide.

5. qaware/from-rest-to-grpc

6. “One cannot not communicate.”
- Paul Watzlawick

7. A Quick History Lesson on Inter Process Communication (IPC)
QAware | 7
REST
2000
by Roy T.
Fielding
RPC
14.01.1976
RFC 707
RPC
Oct 1983
Birrel und
Nielson
DCOM
18.09.1996
Win95
HTTP/1.0
Mai 1996
RFC 1945
CORBA 1.0
Oct 1991
CORBA 2.0
August 1996
HTTP/1.1
Juni 1999
RFC 2616
CORBA 2.3
Juni 1999
Java RMI
Feb 1997
JDK 1.1
XML-RPC
1998
SOAP 1.2
2003
CORBA 3.0
July 2002
RESTful
Applications
2014 (?)
HTTP/2.0
Mai 2015
RFC 7540
gRPC 1.0
Aug 2016

8. Agenda
QAware | 8
QAware | 8
QAware | 8
REST Beer
Service
REST Beer
Service
application/json
application/x-protobuf
gRPC Beer
Service
gRPC Beer
Service
gRPC Beer
Web UI
gRPC Beer
Client
gRPC REST
Gateway
application/json
gRPC LB
Nginx
gRPC
gRPC
gRPC
gRPC
gRPC
Web UI
gRPC Web
Envoy
TypeScript

9. HTTP/1.1 200 OK
Content-Length: 139
Content-Type: application/json; charset=utf-8
Date: Wed, 10 Nov 2021 10:21:54 GMT
{
"alcohol": 5.6,
"asin": "B01AU6LWNC",
"brand": "Augustiner Brauerei München",
"country": "Germany",
"name": "Edelstoff Exportbier",
"type": "Lager"
}
GET /api/beers/B01AU6LWNC HTTP/1.1
Accept: application/json
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:8080
User-Agent: HTTPie/2.5.0
REST APIs
GET /api/beers
POST /api/beers
GET /api/beers/{asin}
PUT /api/beers/{asin}
DELETE /api/beers/{asin}
„Pretty URLs returning JSON“
— @hhariri
Nouns
Verbs
Request
Response

10. Richardson REST Maturity Model
QAware | 10
https://martinfowler.com/articles/richardsonMaturityModel.html
POST /bookingService HTTP/1.1
[various other headers]
<makeBookingRequest date="2010-01-04" persons="2"/>
POST /bookings HTTP/1.1
[various other headers]
<getBookingRequest id="ID-1234567890" user"lreimer"/>
GET /bookings/1234567890?user=lreimer HTTP/1.1
Accept: application/json
[various other headers]
GET /bookings/1234567890?user=lreimer HTTP/1.1
Accept: application/json
Link: /users/lreimer
[various other headers]

11. QAware | 11
1. The network is reliable
2. Latency is zero
3. Bandwidth is infinite
4. The network is secure
5. Topology doesn’t change
6. There is one administrator
7. Transport cost is zero
8. The network is homogeneous
The 8 Fallacies of Distributed Computing

12. There is no Readability in ISO 25010!
QAware | 12
Software Product
Quality
(ISO 25010)
● Modularity
● Reusability
● Analysability
● Modifiability
● Testability
Maintainability
● Confidentiality
● Integrity
● Non-repudiation
● Authenticity
● Accountability
Security
● Adaptability
● Installability
● Replaceability
Portability
● Co-existence
● Interoperability
Compatibility
● Maturity
● Availability
● Fault Tolerance
● Recoverability
Reliability
● Time Behaviour
● Resource Utilization
● Capacity
Efficiency
● Completeness
● Correctness
● Appropriateness
Functional Suitability
● Operability
● Learnability
● UI Aesthetics
● Accessibility
Usability

13. Protocol Buffers are a language-neutral, platform-neutral extensible
mechanism for serializing structured data.
QAware | 13
■ https://developers.google.com/protocol-buffers
■ Like XML or JSON - just smaller, faster and easier!
■ Google Protobuf uses an efficient binary format to serialize data structures.
■ An Interface Definition Language (IDL) is used to define data structures and message payloads. Many primitive types,
enums, maps, arrays, nested types.
■ Protocol Buffers supports code generation for Java, Python, Objective-C, C++, Kotlin, Dart, Go, Ruby und C#.
■ Protobuf supports evolution as well as extension of schemas. Backwards and forwards compatibility are supported:
– you must not change the tag numbers of any existing fields.
– you may delete fields.
– you may add new fields but you must use fresh tag numbers (i.e. tag numbers that were never used in this
protocol buffer, not even by deleted fields).

14. syntax = "proto3";
option java_package = "hands.on.grpc";
option java_outer_classname = "BeerProtos";
package beer;
message Beer {
string asin = 1;
string name = 2;
string brand = 3;
string country = 4;
float alcohol = 5;
enum BeerType{
IndianPaleAle = 0;
SessionIpa = 1;
Lager = 2;
}
BeerType type = 6;
}
// Protobuf marshalling
protoBeer = BeerProtos.Beer.newBuilder()
.setAsin("B079V9ZDNY")
.setName("Drunken Sailor")
.build();
byte[] bytes = protoBeer.toByteArray();
// Protobuf unmarshalling
protoBeer = BeerProtos.Beer.parseFrom(bytes);
$ ./gradlew generateProto
$ protoc -I=$SRC_DIR --java_out=$DST_DIR $SRC_DIR/beer.proto

15. JSON vs Protobuf Performance
QAware | 15
■ Protobuf on a non-compressed environment, the requests took 78% less time than the JSON requests.
The binary format performed almost 5 times faster than the text format.
■ Protobuf requests on a compressed environment, the difference was even bigger. Protobuf performed 6 times faster, taking
only 25ms to handle requests that took 150ms on a JSON format.
https://auth0.com/blog/beating-json-performance-with-protobuf/
https://blog.qaware.de/posts/binary-data-format-comparison/
Disclaimer: please perform your own benchmarks for your specific use case!

16. Agenda
QAware | 16
QAware | 16
QAware | 16
REST Beer
Service
REST Beer
Service
application/json
application/x-protobuf
gRPC Beer
Service
gRPC Beer
Service
gRPC Beer
Web UI
gRPC Beer
Client
gRPC REST
Gateway
application/json
gRPC LB
Nginx
gRPC
gRPC
gRPC
gRPC
gRPC
Web UI
gRPC Web
Envoy
TypeScript

17. gRPC in a Nutshell.
■ A modern, high performance, open source and universal RPC framework.
■ Uses HTTP/2 as modern Web-friendly transport protocol (Multiplexing, TLS, compression, …)
■ Supports several types of communication: classic request-response as well as streaming from Client-side, Server-
side, Uni- and Bi-Directional
■ Uses Protocol Buffers as efficient binary payload format
■ Support various load balancing options: proxy, client-side and look-aside balancing
■ Flexible support for tracing, health checks and authentication
■ Client and server code can be generated from the IDL easily for several languages
– https://github.com/grpc/grpc-go
– https://buf.build
■ gRPC is a CNCF incubating project
QAware | 17

18. syntax = "proto3";
option java_package = "hands.on.grpc";
option java_outer_classname = "BeerProtos";
import "google/protobuf/empty.proto";
package beer;
service BeerService {
rpc AllBeers (google.protobuf.Empty) returns (GetBeersResponse) {}
rpc GetBeer (GetBeerRequest) returns (GetBeerResponse) {}
rpc CreateBeer (CreateBeerRequest) returns (google.protobuf.Empty) {}
rpc UpdateBeer (UpdateBeerRequest) returns (google.protobuf.Empty) {}
rpc DeleteBeer (DeleteBeerRequest) returns (google.protobuf.Empty) {}
}
// more Protobuf message definitions ...

19. Agenda
QAware | 19
QAware | 19
QAware | 19
REST Beer
Service
REST Beer
Service
application/json
application/x-protobuf
gRPC Beer
Service
gRPC Beer
Service
gRPC Beer
Web UI
gRPC Beer
Client
gRPC REST
Gateway
application/json
gRPC LB
Nginx
gRPC
gRPC
gRPC
gRPC
gRPC
Web UI
gRPC Web
Envoy
TypeScript

20. The gRPC ecosystem in a Nutshell.
■ Different projects from the gRPC ecosystem enable good interoperability
– gRPC Gateway
https://grpc-ecosystem.github.io/grpc-gateway/
– gRPC Web
https://grpc.io/docs/platforms/web/quickstart/
■ Support various load balancing options: proxy, client-side and look-aside balancing
– Nginx
https://nginx.org/en/docs/http/ngx_http_grpc_module.html
– Envoy https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/other_protocols/grpc
QAware | 20

21. import "google/protobuf/empty.proto";
import "google/api/annotations.proto";
service BeerService {
rpc AllBeers (google.protobuf.Empty) returns (GetBeersResponse) {
option (google.api.http) = { get: "/api/beers" };
}
rpc GetBeer (GetBeerRequest) returns (GetBeerResponse) {
option (google.api.http) = {
get: "/api/beers/{asin}"
response_body: "beer"
};
}
rpc CreateBeer (CreateBeerRequest) returns (google.protobuf.Empty) {
option (google.api.http) = {
post: "/api/beers"
body: "*"
};
}
// more definitions …
}
Map gRPC call to GET request path
Map {asin} path param to request
Use beer field as response body
Map POST body to request

22. North-South
communication
with REST
East-West
communication
with gRPC
N
S
E
W
Ingress
Egress

23. We did it again!
1. Platz der besten Arbeitgeber in
der Branche IKT
(101-250 Mitarbeitende)

24. qaware.de
QAware GmbH
Aschauer Straße 32
81549 München
Tel. +49 89 232315-0
info@qaware.de
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