Table of Contents
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
1. Why Distributed?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The Single-Threaded Nature of JavaScript
Quick Node.js Overview
The Node.js Event Loop
Event Loop Phases
Code Example
Event Loop Tips
Sample Applications
Service Relationship
Producer Service
Consumer Service
1
6
9
10
11
14
15
16
17
18
2. Protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Request and Response with HTTP
HTTP Payloads
HTTP Semantics
HTTP Compression
HTTPS / TLS
JSON over HTTP
The Dangers of Serializing POJOs
API Facade with GraphQL
GraphQL Schema
Queries and Responses
22
23
25
26
29
34
35
36
37
38
iii
GraphQL Producer
GraphQL Consumer
RPC with gRPC
Protocol Buffers
gRPC Producer
gRPC Consumer
40
43
45
45
48
50
3. Scaling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
The Cluster Module
A Simple Example
Request Dispatching
Cluster Shortcomings
Reverse Proxies with HAProxy
Introduction to HAProxy
Load Balancing and Health Checks
Compression
TLS Termination
Rate Limiting and Back Pressure
SLA and Load Testing
Introduction to Autocannon
Running a Baseline Load Test
Reverse Proxy Concerns
Protocol Concerns
Coming Up with SLOs
53
54
57
58
61
63
64
69
70
72
75
76
76
80
84
87
4. Observability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Environments
Logging with ELK
Running ELK via Docker
Transmitting Logs from Node.js
Creating a Kibana Dashboard
Running Ad-Hoc Queries
Metrics with Graphite, StatsD, and Grafana
Running via Docker
Transmitting Metrics from Node.js
Creating a Grafana Dashboard
Node.js Health Indicators
Distributed Request Tracing with Zipkin
How Does Zipkin Work?
Running Zipkin via Docker
Transmitting Traces from Node.js
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92
93
94
95
98
100
102
103
104
106
108
111
112
115
115
Visualizing a Request Tree
Visualizing Microservice Dependencies
Health Checks
Building a Health Check
Testing the Health Check
Alerting with Cabot
Create a Twilio Trial Account
Running Cabot via Docker
Creating a Health Check
118
119
120
121
124
124
125
126
127
5. Containers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Introduction to Docker
Containerizing a Node.js Service
Dependency Stage
Release Stage
From Image to Container
Rebuilding and Versioning an Image
Basic Orchestration with Docker Compose
Composing Node.js Services
Internal Docker Registry
Running the Docker Registry
Pushing and Pulling to the Registry
Running a Docker Registry UI
133
140
141
143
146
148
151
152
156
157
158
160
6. Deployments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Build Pipeline with Travis CI
Creating a Basic Project
Configuring Travis CI
Testing a Pull Request
Automated Testing
Unit Tests
Integration Tests
Code Coverage Enforcement
Deploying to Heroku
Create a Heroku App
Configure Travis CI
Deploy Your Application
Modules, Packages, and SemVer
Node.js Modules
SemVer (Semantic Versioning)
npm Packages and the npm CLI
165
165
167
168
170
172
174
177
183
184
185
187
190
191
193
197
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Internal npm Registry
Running Verdaccio
Configuring npm to Use Verdaccio
Publishing to Verdaccio
204
205
205
205
7. Container Orchestration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Introduction to Kubernetes
Kubernetes Overview
Kubernetes Concepts
Starting Kubernetes
Getting Started
Deploying an Application
Kubectl Subcommands
Kubectl Configuration Files
Service Discovery
Modifying Deployments
Scaling Application Instances
Deploying New Application Versions
Rolling Back Application Deployments
210
210
211
214
214
219
219
222
226
232
232
233
235
8. Resilience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
The Death of a Node.js Process
Process Exit
Exceptions, Rejections, and Emitted Errors
Signals
Building Stateless Services
Avoiding Memory Leaks
Bounded In-Process Caches
External Caching with Memcached
Introducing Memcached
Running Memcached
Caching Data with Memcached
Data Structure Mutations
Database Connection Resilience
Running PostgreSQL
Automatic Reconnection
Connection Pooling
Schema Migrations with Knex
Configuring Knex
Creating a Schema Migration
Applying a Migration
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239
240
242
247
249
251
252
256
257
258
259
260
262
262
263
269
272
274
275
276
Rolling Back a Migration
Live Migrations
Idempotency and Messaging Resilience
HTTP Retry Logic
Circuit Breaker Pattern
Exponential Backoff
Resilience Testing
Random Crashes
Event Loop Pauses
Random Failed Async Operations
279
280
284
286
289
289
293
294
294
295
9. Distributed Primitives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
The ID Generation Problem
Introduction to Redis
Redis Operations
Strings
Lists
Sets
Hash
Sorted Sets
Generic Commands
Other Types
Seeking Atomicity
Transactions
Lua Scripting
Writing a Lua Script File
Loading the Lua Script
Tying It All Together
298
301
302
304
305
307
308
310
311
312
313
315
317
318
320
322
10. Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Wrangling Repositories
Recognizing Attack Surface
Parameter Checking and Deserialization
Malicious npm Packages
Application Configuration
Environment Variables
Configuration Files
Secrets Management
Upgrading Dependencies
Automatic Upgrades with GitHub Dependabot
Manual Upgrades with npm CLI
326
328
328
331
332
333
334
337
339
340
342
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Unpatched Vulnerabilities
Upgrading Node.js
Node.js LTS Schedule
Upgrade Approach
344
346
346
347
A. Installing HAProxy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
B. Installing Docker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
C. Installing Minikube & Kubectl. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355
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