Shared-Lock – Go-based implementation of distributed lock service

Published at

Mar 12, 2025

Main Article

https://github.com/tentens-tech/shared-lock

Shared Lock

This repository contains a Go-based implementation of a shared lock service using etcd. The service provides endpoints for creating and maintaining leases, ensuring distributed coordination and synchronization.

How to build this project

To build it:

go build -o shared-lock main.go

To build docker image:

docker build -t shared-lock:latest -f deployment/Dockerfile .

How to run this project

To run this project, use:

./shared-lock serve

Service configuration

Possible configuration via env params:

Environment Variable	Default Value	Description
SHARED_LOCK_SERVER_PORT	8080	Port on which the server will run
SHARED_LOCK_SERVER_READ_TIMEOUT	10s	Server read timeout duration
SHARED_LOCK_SERVER_WRITE_TIMEOUT	10s	Server write timeout duration
SHARED_LOCK_SERVER_IDLE_TIMEOUT	120s	Server idle timeout duration
SHARED_LOCK_SERVER_SHUTDOWN_TIMEOUT	10s	Server shutdown timeout duration
SHARED_LOCK_ETCD_ADDR_LIST	localhost:2379	Comma-separated list of etcd endpoints
SHARED_LOCK_ETCD_TLS	false	Enable TLS for etcd connections
SHARED_LOCK_CA_CERT_PATH	/etc/etcd/ca.crt	Path to the CA certificate for etcd
SHARED_LOCK_CLIENT_CERT_PATH	/etc/etcd/client.crt	Path to the client certificate for etcd
SHARED_LOCK_CLIENT_KEY_PATH	/etc/etcd/client.key	Path to the client key for etcd
SHARED_LOCK_DEBUG	false	Toggle for debug mode

How to deploy this project

For this tool to work, you'll need live etcd installation.

As long as etcd mostly used as a part of Kubernetes cluster, we provide examplar installation manifest for the shared lock in deployment/kubernetes-example.yaml.

How to use shared-lock server

Example

Exampler app that demonstrates shared-lock usage in case of need to guarantee that some app will run only in one instance can be found at the example dir.

Endpoints

Create Lease
- URL: /lease
- Method: POST
- Headers:
  - x-lease-ttl: (Optional) The TTL (Time To Live) for the lease.
- Request Body:
  - JSON object representing the lease details.
- Responses:
  - 202 Accepted: Lease request accepted.
  - 201 Created: Lease successfully created.
  - 500 Internal Server Error: Failed to create lease.
- Example:
```
curl -X POST http://localhost:8080/lease \
     -H "Content-Type: application/json" \
     -H "x-lease-ttl: 60s" \
     -d '{"key": "value"}'
```
Keep Alive Lease
- URL: /keepalive
- Method: POST
- Request Body:
  - JSON object representing the lease details.
- Responses:
  - 204 No Content: Lease successfully prolonged.
  - 400 Bad Request: Failed to unmarshal request body.
  - 500 Internal Server Error: Failed to parse lease ID or prolong lease.
- Example:
```
curl -X POST http://localhost:8080/keepalive \
     -H "Content-Type: application/json" \
     -d "12345"
```
Health Check
- URL: /health
- Method: GET
- Responses:
  - 200 OK: Server is healthy.
- Example:
```
curl -X GET http://localhost:8080/health
```

Error Handling

The server will respond with appropriate HTTP status codes and error messages in case of failures.
Common error responses include:
- 400 Bad Request: Invalid request body.
- 500 Internal Server Error: Internal server error.

Example Usage

Create a Lease:

curl -X POST http://localhost:8080/lease \
     -H "Content-Type: application/json" \
     -H "x-lease-ttl: 60s" \
     -d '{"key": "value"}'

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