Community Hangouts
29th March 2018
Dara Hayes
dara.hayes@redhat.com
@darahayess
@darahayes
I think Node is not the best system to build a massive web server. I would use Go for that. And honestly, that’s the reason why I left Node. It was the realization that: oh, actually, this is not the best server-side system ever.
Ryan Dahl - Creator of Node.js
HTTP Frameworks/Libraries
The built in net/http library is really good
But routing is hard
Gorilla Mux is our friend
net/http + gorilla/mux = $$$
Dependency Management
also known as 'vendoring'
Dependency Management (vendoring)
dep is the official experiment, but not yet the official tool
Deps are defined in Gopkg.toml and Gopkg.lock
$ dep init $ dep ensure -add github.com/user/library
Project Structure
.
├── Gopkg.lock
├── Gopkg.toml
├── README.md
├── cmd # Entry Points or executables in here
│ └── my-app
│ └── my-app.go
├── pkg # App modules/business logic stuff in here
│ ├── business
│ ├── config
│ ├── db
│ └── web
└── vendor # Dependencies are in here
Dependency Injection & Interfaces
HTTP Handlers
Business Logic
Database
App Configuration
Use environment variables and fallback to sensible defaults
The app should start (in local dev) with zero config
Testing
Testing Framework is built in!
Excellent HTTP Testing capabilities
Dependency Injection allows us to easily test components in isolation
Test files are normally kept in the same directory
Good Practice to separate integration tests and unit tests
Code Coverage
Code Coverage reporting built in!
Not easy to aggregate coverage across multiple packages
(example shown later)
go test -cover -coverprofile=coverage.out
Upload to coveralls.io as part of CI using goveralls
Build & Test Commands
Use Make for common build and test commands
$ make test
$ make test_integration
$ make build
$ make build_linux
$ make docker_build
$ make docker_release
...
Docker
FROM centos
ARG BINARY=./go-hello-server
EXPOSE 4000
COPY ${BINARY} /opt/go-hello-server
CMD "/opt/go-hello-server"
Build the binary first, then pass into the image
The CI environment is guaranteed to be clean.
Why?
ONE super simple, low maintenance Dockerfile
Simplest developer workflow
Works in dev and in prod
Easiest way to build any version of the project, anytime.
Aim for simplicity, only complicate things if you really need to
Keeps custom build tooling to a minimum
Continuous Integration & Release
poorly documented black magic rituals
unnecessary amounts of setup & coordination
Controversial Opinion
If your release / deploy process can't be described in a few short bullet points, you've got problems.
Let's make it ridiculously easy
CI/CD Recipe for Success
Use the concept of jobs
- build - test - push - deploy
Define sequences of jobs and execute things based on conditions.
Small tasks with one purpose
smaller == Lower probability of failure
single purpose == Modular and reusable
Always look for off the shelf tooling first
Pro Tip
Release process should have one entrypoint
less parameters == less room for error
git tags are fantastic
demo
end 🍕
Aerogear Community Hangout 29 March 2018
By Dara Hayes
Aerogear Community Hangout 29 March 2018
This presentation is the Golang Hello World Server on Steroids. In addition to 'Hello World' This presentation demonstrates approaches for unit tests, parsing and sending JSON, handling environment variables, using interfaces and dependency injection, Building Docker Images and Setting up automated releases in a CI/CD environment.
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