URL Shortener service

Dependencies

Deployment

Podman utility was used to deploy the service. It has better integration with Kubernetes than the mainstream container tool – Docker, but still uses compliant container formats.

Code generation

protobuf used for gRPC wrappers and swagger file code generation.

To install it on rhel-like linux distributions use this command:

# enterprise linux 9
sudo dnf install protobuf-devel

The following version of the utility was used:

$ protoc --version
libprotoc 25.0

protoc dependencies:

gRPC wrappers and swagger file were generated this way:

protoc -I proto --go_out=./internal/pb --go_opt paths=source_relative --go-grpc_out=./internal/pb --go-grpc_opt paths=source_relative --grpc-gateway_out=./internal/pb --grpc-gateway_opt paths=source_relative --openapiv2_out=./api proto/url-shortener.proto

Mocks was generated from contract.go files with mockgen utility to write unit tests, the result is two files:

$ find . -name contract.go
./internal/service/contract.go
./internal/controller/contract.go
$ # they both have go-generate-related command at the top of the file
$ head -n1 ./internal/service/contract.go
//go:generate mockgen -source ${GOFILE} -destination mocks_test.go -package ${GOPACKAGE}_test
$ go generate ./...
$ find . -name mocks_test.go
./internal/service/mocks_test.go
./internal/controller/mocks_test.go

Build

Example of service building command:

go build -o bin/service-url-shortener ./cmd

But to simplify future deployment better build container images:

podman build . -f build/db/Containerfile -t service-url-shortener-db
podman build . -f build/app/Containerfile -t service-url-shortener-app

Deploy

The service looks up for an required non-empty environment variable STORAGE_TYPE to select the corresponding one storage type.

Practically it is configured by selecting the corresponding k8s pod configuration. Both of them are in /deploy directory.

To deploy service with postgres-like storage run the following command:

podman kube play --configmap deploy/app-configmap.yml deploy/postgres-pod.yml

For the in-memory-like storage:

podman kube play --configmap deploy/app-configmap.yml deploy/in-memory-pod.yml

The following command will stop and remove all related containers. Use --force flag for postgres-like deployment to prune related to database persistent volume.

podman kube down deploy/STORAGE-TYPE-pod.yml

Connect

There is generated swagger file describing how to send requests to service. Some examples:

POST

curl --location 'localhost:8081/reduce' --header 'Accept: application/json' --header 'Content-Type: text/plain' --data '{"originUrl": "https://www.ozon.ru/"}'

GET:

curl --location 'localhost:8081/get/tUaVM2YjHq' --header 'Accept: application/json'

Test

There are 3 modules that have been covered by unit-tests, to run them run:

go test ./internal/controller
go test ./internal/entity
go test ./internal/service