fossabot/charon

Charon

Backend services for caching and displaying geospatial data

Getting Started

These instructions will get you a copy of the project up and running on your system. This is intended to run on an ubuntu machine but can be run anywhere you have docker installed.

Dependencies

• make
• unzip (to unzip terraform)
• docker

Make is most likely already installed on your system. To install docker follow the instructions here or use the install script:

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Deployment

There are a couple of steps to run the services.

0. Clone the repository to your machine.

   git clone https://github.com/chronark/charon.git
   cd charon

1. Build all necessary docker images if you don't have them alrady.

   make build

2. Get and initialize Terraform, a infrastructure management and provisioning tool.

   make init

3. Create a terraform plan

   make plan

4. Apply the plan

   make apply

Visit http://localhost to see the map.

Services

Filecache

Discovery name: charon.srv.filecache

Filecache is a basic cache that writes or reads bytes to and from the disk. The cache is mounted on the host as ./volumes/filecache and can be backed up or modified by removing or adding files on the host machine.

Gateway

The HTTP API gateway to interact with all microservices. Exposes various routes to fetch data. Listens on port 52000 Routes:

• /geocoding/forward?query=XYZ calls the geocoding service.
• /geocoding/reverse?lat=1.0&lon=1.0 calls the geocoding service.
• /tile?x=0&y=0&z=0calls the tiles service.

Geocoding

Discovery name: charon.srv.geocoding.nominatim or charon.srv.geocoding.mapbox

Geocoding has two handlers: Nominatim and Mapbox They both receive a forward or reverse geocoding search and search the cache. In case of a miss they will query their respective 3rd party APIs, write to cache and return the result. The cache is mounted on the host as ./volumes/geocoding and can be backed up or modified by removing or adding files on the host machine.

Tiles

Discovery name: charon.srv.tiles.osm or charon.srv.geocoding.mapbox

Tiles has two handlers: osm and Mapbox They both receive a tile request and search the cache. In case of a miss they will query their respective 3rd party APIs, write to cache and return the result.

Built With

• go
• docker
• gRPC - Internal communication
• terraform - Infrastructure management
• go-micro - Microservice framework

Development

To get up and running as fast as possible you can use Vagrant to start and provision a local ubuntu:18.04 machine

vagrant up

Charon makes use of protobuf for the internal communication. In order to compile the protobuf definition you need to install:

go get google.golang.org/grpc
go get github.com/golang/protobuf/protoc-gen-go
go get github.com/micro/protoc-gen-micro

Then run make proto to compile all protobuf definitions at once.

License