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Creating a microservice for the 1st time with go Henrique Vicente

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Go is an open source programming language that makes it easy to build simple, reliable, and efficient software. golang.org Robert Griesemer, Rob Pike and Ken Thompson started sketching the goals for a new language on the white board on September 21, 2007.

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Go is a programming language designed by Google to help solve Google's problems, and Google has big problems. https://talks.golang.org/2012/splash.article

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An attempt to combine the ease of programming of an interpreted, dynamically typed language with the efficiency and safety of a statically typed, compiled language.

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Influenced by • C family (basic syntax) • Pascal / Modula / Oberon family (declarations, packages) • Newsqueak, Limbo (concurrency) • Unix

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Design • Multi-value returns • No exception handling. Pleasant error handling.
 http://blog.golang.org/error-handling-and-go • Gourotines instead of threads • Object-oriented? Yes and no.
 No type hierarchy. Interfaces. • No pointer arithmetic for safety:
 no memory illegal address risk • Garbage collected

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Quality tools • go fmt • go lint • go vet • go test • go tool cover

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go get github.com/henvic/picel • Programming time?

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• Package main: executable program • Others: shared libraries • Imports:
 - don’t use relative internally
 - use the path to where the repo is published • Subpackages = subdirectories

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No official package manager • The designers of the language decided not to do it for a reason. • But what if you want to guarantee a specific package version?
 
 https://code.google.com/p/go-wiki/wiki/ PackageManagementTools

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many alternatives • godeps • gpm: https://github.com/pote/gpm

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Building • go build • You get a single binary by default. • gox tool to build to multiple platforms easily
 or just use https://gobuilder.me/

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The go way • Unused variable? • Unused import? • Unused?
 
 = No compiling :( … :) • Just discovered: fix it automagically :)
 http://godoc.org/golang.org/x/tools/cmd/goimports
 Productivity += 1000 • godoc -http=:6000 to see the docs on your computer or use godoc.org

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$GOPATH • Go likes to have all your src, pkg, bin inside a $GOPATH • But don’t worry. This doesn’t matter for end users of your application, given you’re release compiled binaries.

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Useful packages, methods • fmt.Println(“like console.log”) • fmt.Sprintf(“%+v is %v old”, person, person.Age()) • flag: ./cmd -backend “https://google.com/”
 Flag: backend, value: https://google.com/ • number, err := strcov.Atoi(“2442”)
 number is 2442 (int), err is nil

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OOP: image.Name()
 with multiple return params Code: https://goo.gl/Ma2ITn

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“Dockerifying • Docker is built in go • We’ve a microservice that is designed to work with default options • Why not build a docker container for it?

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Dockerfile FROM golang:onbuild MAINTAINER Henrique Vicente RUN apt-get update RUN apt-get install -y \ imagemagick \ webp EXPOSE 8123

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Docker Hub Registry • Add repo for automatic building on Docker Hub Registry to have your package certified • You can install with
 docker pull henvic/picel • See also Dockerfile.dev

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Some nice go projects srvdir

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Questions?