golangRestApiExampleWithDependencyInjection

GO REST API service

Design

• two layered micro service
  • web api controller logic
  • persistence layer
• Data transfer object definition for domain entity data representation
• using dependency injection for each layer for testability
• low ceremony IoC solution for dependency injection karlkfi/inject
• using echo as web api framework
• gomock with mockgen as mocking framework
• test/coverage report (and much more) integrated via build script
• use DATA-DOG/go-sqlmock for persistence tests
• code structure according to thockin/go-build-template

How to Build

set your $GOPATH (applies to unixoid OS', for windows replace all $ENVVARNAME whith %ENVVARNAME% )

get and build project plus build & test dependencies

go get -t -v github.com/ckolumbus/golangRestApiExampleWithDependencyInjection

How to run Tests

go test -v github.com/ckolumbus/golangRestApiExampleWithDependencyInjection/...

How to Run

No special setup needed, database and schema are created automatcially in ./db.sqlite

cd $GOPATH/bin
./golangRestApiExampleWithDependencyInjection

Using MAGE

mage is a go based task runner which implements an internal DSL define tasks and dependencies.

Install mage by running

go get -u -d github.com/magefile/mage
cd $GOPATH/src/github.com/magefile/mage
go run bootstrap.go

After this you can get a list of possbile targets with

cd $GOPATH/src/github.com/ckolumbus/golangRestApiExampleWithDependencyInjection
$GOPATH/bin/mage
$GOPATH/bin/mage -v check
$GOPATH/bin/mage -v install

Output

Targets:
  check               Run tests and linters
  checkVendor         verifies that vendored packages match git HEAD
  fmt                 Run gofmt linter
  install             binary
  lint                Run golint linter
  service             Build binary
  serviceNoGitInfo    Build Service without git info
  serviceRace         Build binary with race detector enabled
  test                Run tests
  test386             Run tests in 32-bit mode
  testCoverHTML       Generate test coverage report
  testRace            Run tests with race detector
  vendor              Install Go Dep and sync vendored dependencies
  vet                 Run go vet linter

Todos

• create build script: use mage
• improve documentation
• integrate mock framework : use gmock
• integrate initial db/schema creation
• investigate possible use of an ORM
• investigate seperation of tests (e.g. controller) into own package and/or directory according to all best practices on the net this seperation should not be done
• add mock generation to build script (example: $GOPATH/bin/mockgen -source pkg/employee/persistence/IPersistEmployee.go -destination controllers/PersistEmployeeMock_test.go -package controllers)
• logging concept
• handling arrays: use elments with or without "*"?
• Vendoring with dep (seems to be the recommenden tool, alternatives are listed in the Go Wiki)
• structured logging support with, possibly with logrus

References

Structure

c.f. code guidlines

Naming conventions

• https://golang.org/doc/effective_go.html#names

Configure Dev Env

• https://github.com/Microsoft/vscode-go/wiki/GOPATH-in-the-VS-Code-Go-extension#gopath-from-goinfergopath-setting

Handling of external Dependency

Install all dependencies, -t includes test dependencies

go get -t ./...

• https://coderwall.com/p/arxtja/install-all-go-project-dependencies-in-one-command

Build

Tests

according to the (test structure][https://golang.org/doc/code.html#Testing] definition the test file are located next to the production code files.

TODO: search for best practices, maybe seperate test from production code

• https://golang.org/pkg/testing/
• https://golang.org/pkg/testing/#hdr-Subtests_and_Sub_benchmarks

Dependency Injection / Inversion of Control

• karlkfi/inject NO change whatsover on existing code when doing ctor injection already
• facebookgo/inject most references one, but IMHO quite some ceremony needed
• magic003/alice somewhat in between the two above

Mocks

• https://github.com/golang/mock
• https://github.com/DATA-DOG/go-sqlmock

Debug

• https://github.com/Microsoft/vscode-go/wiki/Debugging-Go-code-using-VS-Code

other REST examples

• https://github.com/kyawmyintthein/golangRestfulAPISample
• https://github.com/emicklei/go-restful/blob/master/examples

JSON handling

• how to de-/serialze json with correct quoting

Task runner

The goal was to have a go based task runner to stay whitin one technology, my personal preference goes towards internal DSL, i.e. the task description is a go file itself.

There is quite a number of task runners fo go, most are yaml based, some are go based.

YAML

• realize backed by commercial company
• go-task with a nice shell abstraction for cross platform scripting
• godo since 3yrs no update
• myke
• zeus
• tusk

GO

• grift
• mage