linkshortener

go-link-shortener-backend

Back-end of the service for shorting links.

Features

• RESTful API:
  • link model:
    • creating by an URL;
    • getting by a code;
  • representing in a JSON:
    • payloads:
      • of requests;
      • of responses;
    • errors;
• generating link codes:
  • using sequential counters:
    • formatting:
      • formatting a counter as an integer number in the 62 base;
    • storing:
      • storing in a database only counters chunks;
      • storing counters themselves in memory;
    • sharding:
      • sharding counters chunks;
      • selecting a shard of a counter chunk at random;
• sharding links across multiple servers (optionally):
  • supporting individual data storages for each server:
    • Redis database;
    • MongoDB database;
  • supporting specifying of the source server in a link:
    • returning the server ID on link generating;
    • ignoring the server ID:
      • on link getting;
      • on redirecting to a link;
• server:
  • additional routing:
    • redirecting to the link URL by its code;
    • serving static files;
  • storing settings in environment variables;
  • supporting graceful shutdown;
  • logging:
    • logging requests;
    • logging errors;
  • panics:
    • recovering on panics;
    • logging of panics;
• databases:
  • storing links in the MongoDB database;
  • storing counters chunks in the etcd database:
    • using a record version as a counter chunk;
  • caching links in the Redis database;
• distributing:
  • Docker image;
  • Docker Compose configuration.

Installation

Prepare the directory:

$ mkdir --parents "$(go env GOPATH)/src/github.com/thewizardplusplus/"
$ cd "$(go env GOPATH)/src/github.com/thewizardplusplus/"

Clone this repository:

$ git clone https://github.com/thewizardplusplus/go-link-shortener-backend.git
$ cd go-link-shortener-backend

Install dependencies with the dep tool:

$ dep ensure -vendor-only

Build the project:

$ go install ./...

Usage

$ go-link-shortener

Environment variables:

• SERVER_ID — server ID;
• SERVER_STATIC_PATH — path to the project's front-end (default: ./static);
• addresses:
  • SERVER_ADDRESS — server URI (default: :8080);
  • CACHE_ADDRESS — Redis connection URI (default: localhost:6379);
  • STORAGE_ADDRESS — MongoDB connection URI (default: mongodb://localhost:27017);
  • COUNTER_ADDRESS — etcd connection URI (default: localhost:2379);
• time to live of links in Redis:
  • CACHE_TTL_CODE — time to live of links in Redis, stored by their code (e.g. 72h3m0.5s; default: 1h);
  • CACHE_TTL_URL — time to live of links in Redis, stored by their URL (e.g. 72h3m0.5s; default: 1h);
• settings of distributed counters:
  • COUNTER_COUNT — count of distributed counters (default: 2);
  • COUNTER_CHUNK — step of a distributed counter (default: 1000);
  • COUNTER_RANGE — range of a distributed counter (default: 1000000000).

API Description

API description:

• in the Swagger format: docs/swagger.yaml;
• in the format of a Postman collection: docs/postman_collection.json.

Bibliography

1. URL Shortener System Design.
2. Generating Globally Unique Identifiers for Use with MongoDB.

License

The MIT License (MIT)

Copyright © 2019-2021 thewizardplusplus