postgres-grpc-example

Install

Dependencies are managed with Glide. Therefore, make sure it is installed and run this to pull the dependencies.

$ glide install

In addition, the following commands make sure global dependencies are installed.

$ go get -u github.com/golang/protobuf/protoc-gen-go
$ go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway
$ go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger
$ go get -u github.com/mwitkow/go-proto-validators/protoc-gen-govalidators

Build the project with GNU Make.

$ make

Start Postgres

This demo uses PostgreSQL to store user data. As a prerequisite, the database needs to be started in a Docker container.

$ docker run --name postgres -p 5432:5432 -e POSTGRES_PASSWORD=password --rm -d postgres

To connect to the database, the program uses go-pg.

Start server

In one terminal, run this to start the GRPC server. It listens to http://localhost:9090 through GRPC protocol, and it also exposes a Rest API at http://localhost:8080.

$ pg_server

Make Rest requests

Get client access token

The following command obtains an OAuth2 token. This token authorizes a client with id "client".

$ curl -X POST -H 'Content-Type: application/json' -d '{"client_id": "client", "client_secret": "password", "grant_type": "client_credentials"}' 'localhost:8080/oauth/tokens'

One can save the access token into the CLIENT_TOKEN environment variable.

$ CLIENT_TOKEN=$(curl -s -X POST -H 'Content-Type: application/json' -d '{"client_id": "client", "client_secret": "password", "grant_type": "client_credentials"}' 'localhost:8080/oauth/tokens' | jq -r '.access_token')

Create a user

The following command uses the client OAuth2 token to create a user.

$ curl -X POST -H 'Content-Type: application/json' -H "authorization: bearer $CLIENT_TOKEN" -d '{"username": "tfeng", "password": "password"}' localhost:8080/v1/users/create

Authenticate

The following command uses the client OAuth2 token and the username and password to obtain another OAuth2 token that authorizes operations on a specific user.

$ USER_TOKEN=$(curl -s -X POST -H "Authorization: Bearer $CLIENT_TOKEN" -H 'Content-Type: application/json' -d '{"username": "tfeng", "password": "password", "grant_type": "password"}' 'localhost:8080/oauth/tokens' | jq -r '.access_token')

The returned JSON is an OAuth2 token token.

Get the current user

The following command fetches the profile information of the user.

$ curl -H 'Content-Type: application/json' -H "authorization: bearer $USER_TOKEN" localhost:8080/v1/users/get

Make GRPC requests

A GRPC client can directly make requests to the server, without going through the gateway.

$ pg_client

This will execute the same steps as above, i.e., creating a user, logging in as that user, and getting that user's information.