index

Symbols

$PASSWORD variable 171

Numerics

2PC (two-phase commit) 18

A

actors, in hexagonal architecture 48

adapters

implementing 54 – 57

in hexagonal architecture 48 – 49

payment

implementing 71 – 72

overview 69 – 70

using in gRPC 73 – 75

ALTS (Application Layer Transport Security) 6

APIPort interface 53, 74

app:order label 138

app:payment label 138

application core, implementing 51 – 53

application logging 168 – 169

Application struct 53

applications

in hexagonal architecture 48

running 61 – 63

automatic mock generation 111 – 112

automation, for source code generation 40 – 42

average value of numbers 156

B

BackoffExponentialWithJitter option 87

BackoffLinearWithJitter option 87

backward compatibility 43 – 45

adding new fields 43

adding/removing oneof fields 44 – 45

moving fields out of or into oneof fields 45

upgrading client but not server 44

upgrading server but not client 43 – 44

bidirectional streaming 6, 27

blue-green deployment 146 – 147

C

CA (certificate authority) 97

Called() method 109

canary deployment 144, 147

cancellation function 84

CD (continuous deployment) pipeline 127

certificate authority (CA) 97

certificate generation 97 – 98

certificate management 141 – 144

certificate usage in Ingress 143

certificates on client side 144

ClusterIssuer 142 – 143

installation 142

CertificateRequests CRD 142

Certificates CRD 142

Challenges CRD 142

Charge method 72

choreography-based saga 19 – 21

CI/CD pipeline

production-grade use cases 11

circuit breaker pattern 87 – 92

client

certificates on side of 144

configuration for payment stub 72 – 73

handling errors on side of 78 – 79

load balancing on side of 67 – 68

upgrading client but not server 44

upgrading server but not client 43 – 44

client-side load balancing 66

CLIs (command-line interfaces) 48

cluster level logging 158

ClusterIP type 137

ClusterIssuer 142 – 143

ClusterIssuers CRD 142

code generation 5

command channel notation 21

command-line interfaces (CLIs) 48

connecting wires, in interservice communication 27 – 28

container runtime 10 – 11

context function 84

context.Background() parent context 84

continuous deployment (CD) pipeline 127

control plane 130

-cover parameter 111, 123

coverage, test 123 – 124

coverage information 123 – 124

testing in CI pipeline 124

coverage.out report 124

-coverprofile param 111

CRDs (custom resource definitions) 141 – 142

Create endpoint 59 – 60, 74, 76 – 78, 120

Create function 24

Create method 37, 60, 68, 72

CreateOrder request 63

CreateOrderRequest message 32 – 33

CreatePaymentRequest message 24, 35

CreatePaymentResponse message 24

ctx parameter 28

custom resource definitions (CRDs) 141 – 142

D

-d parameter 63

data consistency, handling in microservice architecture 18

database layer, end-to-end tests 117 – 118

db.Get() function verification 114

db.Save() testing 114

dependency injection 61 – 63

deployment 127 – 149

certificate management 141 – 144

certificate usage in Ingress 143

certificates on client side 144

ClusterIssuer 142 – 143

installation 142

Docker 128 – 130

Kubernetes 130 – 141

architecture 130 – 132

deployment 135 – 137

eagle view of microservices deployment 133 – 134

NGINX Ingress controller 140 – 141

resources 132 – 133

Service resource 137 – 139

of monolithic applications 15 – 16

strategies for 144 – 149

blue-green deployment 146 – 147

canary deployment 147

final thoughts on deployment 148 – 149

RollingUpdate 145 – 146

Docker 128 – 130

Docker Compose service definitions 116 – 117

docker login command 130

docker-compose up operation 121

driven actor 48

driver actor 48

E

Elasticsearch, as logging backend 170 – 172

ELK stack (Elasticsearch-Logstash-Kibana) 158

encoding, protocol buffer 33 – 36

end-to-end tests 115 – 123

database layer 117 – 118

Docker Compose service definitions 116 – 117

folder structure for 117

Order service layer 119 – 120

Payment service layer 118 – 119

running tests against stack 120 – 123

specifications 116

error handling

and resilient communication 92 – 95

gRPC error model 93

gRPC error response 93 – 95

in interservice communication 75 – 80

errors with details 77 – 78

handling errors on client side 78 – 79

returning error code and message 76 – 77

running Payment service 80

status codes 75 – 76

error message, gPRC 75

ErrorDetails section 93

F

fault tolerance 5 – 6

Fibonacci function 106

field numbers 33

fields

adding new to messages 43

moving out of or into oneof fields 45

folders

project 50 – 51

structure for end-to-end tests 117

Format function 168

forward compatibility 43 – 45

adding new fields 43

adding/removing oneof fields 44 – 45

moving fields out of or into oneof fields 45

upgrading client but not server 44

upgrading server but not client 43 – 44

FROM keyword 128

G

Get endpoints 120

Get method 54, 56 – 57

go build command 128

go mod init command 51

Go source code, generating 25 – 27

go test command 106

gorm.DB reference 56

gRPC adapter, implementing 57 – 61

gRPC endpoint, calling 63 – 64

gRPC error model 93

gRPC error response 93 – 95

gRPC microservices 3 – 28

audience for book 8

benefits of 4 – 6

code generation and interoperability 5

fault tolerance 5 – 6

microservice architecture 17 – 22

choreography-based saga 19 – 21

handling data consistency 18

orchestration-based saga 21 – 22

saga pattern 18 – 19

monolithic architecture 15 – 16

deployment 15 – 16

production-grade use cases 8 – 13

CI/CD pipeline 11

container runtime 10 – 11

microservices 9 – 10

monitoring and observability 11 – 12

public access 12 – 13

REST vs. RPC 6 – 7

scale cube 16 – 17

X-axis scaling 16

Y-axis scaling 17

Z-axis scaling 17

service discovery 22

when to use 7 – 8

gRPC service-to-service communication 66 – 68

grpc_retry package 87

grpcurl command 58, 144

H

hexagonal architecture

Order service implementation 49 – 64

calling gRPC endpoint 63 – 64

dependency injection and running application 61 – 63

implementing adapters 54 – 57

implementing application core 51 – 53

implementing gRPC adapter 57 – 61

implementing ports 53 – 54

initializing Go project 51

project folders 50 – 51

overview 47 – 49

-html option 124

I

idempotent operations 6

IDL (Interface Definition Language) 5

images, Docker 128 – 130

-import-path parameter 144

Ingress

certificate usage in 143

NGINX Ingress controller 140 – 141

init() function 168 – 169

initializing Go project 51

installation

cert-manager 142

Jaeger 162 – 163

instrumentation, OpenTelemetry 159

int type 33, 35

integration tests 112 – 115

test suite preparation 112 – 113

working with Testcontainers 113 – 115

internal/adapters/grpc package 73

interoperability 5

interservice communication 31 – 46, 65 – 80

backward and forward compatibility 43 – 45

adding new fields 43

adding/removing oneof fields 44 – 45

moving fields out of or into oneof fields 45

upgrading client but not server 44

upgrading server but not client 43 – 44

depending on module and implementing ports and adapters 68 – 75

client configuration for payment stub 72 – 73

implementing payment adapter 71 – 72

implementing payment port 70

payment adapter overview 69 – 70

payment port overview 69

using payment adapter in gRPC 73 – 75

error handling 75 – 80

errors with details 77 – 78

handling errors on client side 78 – 79

returning error code and message 76 – 77

running Payment service 80

status codes 75 – 76

generating stubs 36 – 38

gRPC service-to-service communication 66 – 68

maintaining .proto files 38 – 42

automation for source code generation 40 – 42

proto project structure 38 – 40

protocol buffers 32 – 36

defining message type 32 – 33

protocol buffer encoding 33 – 36

using gRPC for 23 – 28

connecting wires 27 – 28

generating Go source code 25 – 27

working with protocol buffers 24 – 25

IP:port pair 138

Issuers CRD 142

J

Jaeger All in One 161 – 162

Jaeger installation 162 – 163

jaeger namespace 162

Jaeger SPM (service performance monitoring) component 167

jaeger-prometheus Prometheus service name 162

K

Kibana as logging dashboard 172 – 174

kubectl apply command 136

kubectl command-line tool 132

Kubernetes

deployment 130 – 141

architecture 130 – 132

eagle view of microservices deployment 133 – 134

NGINX Ingress controller 140 – 141

overview 135 – 137

resources 132 – 133

Service resource 137 – 139

observability in 161 – 174

application logging 168 – 169

Elasticsearch as logging backend 170 – 172

Jaeger All in One 161 – 162

Jaeger installation 162 – 163

Kibana as logging dashboard 172 – 174

logs collection 169 – 170

OpenTelemetry Collector 162

OpenTelemetry interceptor for Order service 163 – 165

understanding metrics of Order service 165 – 167

L

labels section 136

load balancing

client-side 67 – 68

LoadBalancer Service type 137 – 140, 144

.local domain name 143

logging

application 168 – 169

Elasticsearch as backend for 170 – 172

in observability 157 – 158

Kibana as dashboard for 172 – 174

log collections 169 – 170

M

message fields 43

metrics

and OpenTelemetry 159 – 160

in observability 155 – 157

of Order service, understanding 165 – 167

microservice architecture 17 – 22

choreography-based saga 19 – 21

handling data consistency 18

orchestration-based saga 21 – 22

production-grade use cases 9 – 10

saga pattern 18 – 19

microservice project setup 47 – 64

hexagonal architecture 47 – 49

Order service implementation 49 – 64

calling gRPC endpoint 63 – 64

dependency injection and running application 61 – 63

implementing adapters 54 – 57

implementing application core 51 – 53

implementing gRPC adapter 57 – 61

implementing ports 53 – 54

initializing Go project 51

project folders 50 – 51

minikube tunnel command 143 – 144

mocks

automatic generation of 111 – 112

implementing 108 – 111

working with 107 – 108

modules, depending on 68 – 75

client configuration for payment stub 72 – 73

implementing payment adapter 71 – 72

implementing payment port 70

payment adapter overview 69 – 70

payment port overview 69

using payment adapter in gRPC 73 – 75

monitoring 11 – 12

monolithic architecture 15 – 16

deployment 15 – 16

mTLS (mutual TLS) 96

multistage builds 118, 128

N

New<Service_Name>Client naming convention 28

New<ServiceName>Client function 37

NewAdapter function 56

NewApplication method 53

NewOrder method 52

NewOrderClient(...) function 37

NGINX Ingress controller 140 – 141

nginx instance 134, 141

nginx-ingress chart 141

nginx.conf. NGINX configurations 141

node-level logging 157 – 158

NodePort option 141

NodePort service type 137 – 139

numbers, average value of 156

O

observability 153 – 174

in Kubernetes 161 – 174

application logging 168 – 169

Elasticsearch as logging backend 170 – 172

Jaeger All in One 161 – 162

Jaeger installation 162 – 163

Kibana as logging dashboard 172 – 174

logs collection 169 – 170

OpenTelemetry Collector 162

OpenTelemetry interceptor for Order service 163 – 165

understanding metrics of Order service 165 – 167

logs 157 – 158

metrics 155 – 157

OpenTelemetry 158 – 161

instrumentation 159

instrumentation locations 159

metric backend 159 – 160

service performance monitoring 160 – 161

production-grade use cases 11 – 12

traces 154 – 155

oneof fields

adding/removing 44 – 45

moving fields out of or into 45

OpenTelemetry 158 – 161

instrumentation 159

instrumentation locations 159

metric backend 159 – 160

service performance monitoring 160 – 161

OpenTelemetry Collector 162

OpenTelemetry interceptor for Order service 163 – 165

orchestration-based saga 21 – 22

Order data 19, 52

Order model 54 – 56, 60, 69

order operation 84

Order service 39 – 40, 42

end-to-end tests 119 – 120

implementation 49 – 64

calling gRPC endpoint 63 – 64

dependency injection and running application 61 – 63

implementing adapters 54 – 57

implementing application core 51 – 53

implementing gRPC adapter 57 – 61

implementing ports 53 – 54

initializing Go project 51

project folders 50 – 51

OpenTelemetry interceptor for 163 – 165

understanding metrics of 165 – 167

order_created event 20

order-service, deployment 135

Order:create() method 18

OrderClient interface 37

OrderDatabaseTestSuite type 113 – 114

OrderId struct 55

OrderItem model 54

orders database 118

ORM (Object Relational Mapping) library 54

otelgrpc package 164

outputs section 171

P

payment adapter

implementing 71 – 72

overview 69 – 70

using in gRPC 73 – 75

Payment Create operation 166

Payment operation 18

payment port

implementing 70

Payment service 39 – 40, 42

end-to-end tests 118 – 119

payment stub, client configuration for 72 – 73

payment_created event 20

payment_failed event 20

payment-related calls 108

payment.Charge() call 110

payments database 118

PENDING state 20, 74

performance benefits of gRPC microservices 4

PlaceOrder 52 – 53, 59, 74, 78, 107 – 109, 154, 161

-plaintext parameter 63

pods, Kubernetes 134

ports

implementing 53 – 54

in hexagonal architecture 48

payment

implementing 70

ports.DBPort interface 52

PR (pull request) 124

production-grade use cases 8 – 13

CI/CD pipeline 11

container runtime 10 – 11

microservices 9 – 10

monitoring and observability 11 – 12

public access 12 – 13

project folders 50 – 51

project structure, proto 38 – 40

promo_code option 45

-proto file 144

.proto files, maintaining 38 – 42

automation for source code generation 40 – 42

proto project structure 38

protocol buffer compiler 25

installation 36

using 36 – 38

protocol buffers 32 – 36

defining message type 32 – 33

encoding 33 – 36

in interservice communication 24 – 25

public access 12 – 13

R

replicas definition 136

replyTo channel 21

replyToChannel parameter 20

reserved keyword 33

resilient communication 81 – 102

error handling 92 – 95

gRPC error model 93

gRPC error response 93 – 95

resiliency patterns 82 – 92

circuit breaker pattern 87 – 92

retry pattern 85 – 87

timeout pattern 82 – 85

securing gRPC communication 95 – 101

certificate generation 97 – 98

gRPC TLS credentials 99 – 101

TLS handshake 95 – 96

ResourceExhausted response code 86 – 87

REST (Representational State Transfer) 6 – 7

retry pattern 85 – 87

RollingUpdate deployment 145 – 146

round-robin algorithm 67

route operation 141

RPC (Remote Procedure Call) 6 – 7

running application 61 – 63

S

saga pattern

choreography-based saga 19 – 21

orchestration-based saga 21 – 22

overview 18 – 19

Save method 54, 56 – 57

scale cube 16 – 17

X-axis scaling 16

Y-axis scaling 17

Z-axis scaling 17

scaling monolithic applications 16

SDKs (software development kits) 79

server

load balancing on side of 66

upgrading client but not server 44

upgrading, but not client 43 – 44

service discovery 22

service performance monitoring 160 – 161

Service resource, Kubernetes 137 – 139

Service types 137

Service YAML definition 137

service-level agreement (SLA) 155

service-level indicator (SLI) 155

service-level objective (SLO) 155 – 157

service-to-service communication 66 – 68

Service, LoadBalancer Type 137

<ServiceName>Client function 37

Service – pod relationship 147

SetupSuite section 120

Shipping operation 18

Shipping service 39 – 40, 42

Shipping stub 24

SLA (service-level agreement) 155

SLI (service-level indicator) 155

SLO (service-level objective) 155 – 157

software development kits (SDKs) 79

source code generation automation 40 – 42

spec section 136

stack, running tests against 120 – 123

status codes, in error handling 75 – 76

stubs

client and server 4

generating 36 – 38

Payment and Shipping 24

payment, client configuration for 72 – 73

-subj parameter 97

SUT (system under test) 105

svc.cluster.local suffix 162

T

TearDownSuite 120, 122

test suite preparation 112 – 113

Testcontainers 113 – 115

testing microservices 103 – 126

end-to-end tests 115 – 123

database layer 117 – 118

Docker Compose service definitions 116 – 117

folder structure for 117

Order service layer 119 – 120

Payment service layer 118 – 119

running tests against stack 120 – 123

specifications 116

integration tests 112 – 115

test suite preparation 112 – 113

working with Testcontainers 113 – 115

test coverage 123 – 124

coverage information 123 – 124

testing in CI pipeline 124

testing pyramid 104 – 105

unit tests 105 – 112

automatic mock generation 111 – 112

implementing mock 108 – 111

system under test 105

test workflow 106 – 107

working with mocks 107 – 108

testing pyramid 104 – 105

TestSetupSuite function 113

TestSetupTest method 112

TestTearDownSuite method 112

timeout pattern 82 – 85

TLS (Transport Layer Security) 4

gRPC credentials 99 – 101

handshake 95 – 96

traces, in observability 154 – 155

two-phase commit (2PC) 18

U

UAT (user acceptance testing) 11

Unavailable response code 86 – 87

unit tests 105 – 112

automatic mock generation 111 – 112

implementing mock 108 – 111

system under test 105

test workflow 106 – 107

working with mocks 107 – 108

upgrading

client, but not server 44

server, but not client 43 – 44

V

VCS (Version Control System) 11

W

wires, connecting in interservice communication 27 – 28

WithBackoff configuration 87

WithCodes configuration 87

WithMax configuration 87

WithStreamingInterceptor interceptor usage 87

WithUnaryInterceptor interceptor usage 87

worker nodes 130

X

X-axis scaling 16

Y

Y-axis scaling 17

Z

Z-axis scaling 17