PoC .NET ETCD

A proof of concept demonstrating how to integrate etcd — a strongly consistent, distributed key-value store — with .NET (C#).

This PoC evaluates the feasibility of using etcd in .NET-based infrastructure and services, covering basic CRUD operations, change watching, and atomic transactions.

Why etcd?

Unlike Redis, etcd is strongly consistent (via the Raft consensus algorithm), making it a better choice for storing critical distributed-system data such as configuration, service discovery state, and distributed locks.

Prerequisites

Running Locally

1. Start etcd via Docker Compose

docker compose up -d

This starts a single etcd node on port 2379 with no authentication and a persistent volume.

2. Run the .NET PoC

dotnet run --project Src/POCTemplate

Expected output

=== etcd PoC with .NET ===

--- Basic CRUD ---
PUT name = Guilherme
GET name = Guilherme
GET name (after update) = Updated
GET name (after delete) = "" (empty string means key not found)

--- Watch ---
  Watch event: dog -> "sits" (Put)
  Watch event: dog -> "runs" (Put)
  Watch event: dog -> "" (Delete)

--- Transaction (atomic multi-key write) ---
  Watch received 2 event(s) in one response:
    animals/cow -> "moo" (Put)
    animals/chicken -> "cluck" (Put)
GET animals/cow     = moo
GET animals/chicken = cluck

Done.

3. Stop etcd

docker compose down

To also remove the persistent volume:

docker compose down -v

etcd CLI Quick Reference

If you have etcdctl installed (or via the container), you can interact with the store directly:

# Set a key
etcdctl put mykey "myvalue"

# Get a key
etcdctl get mykey

# Delete a key
etcdctl del mykey

# Watch a key for changes
etcdctl watch mykey

# List all keys with a prefix
etcdctl get animals/ --prefix

# Run via the Docker container
docker exec -it <container-name> etcdctl put foo bar

Project Structure

Src/
  POCTemplate/
    Program.cs          # etcd demo: CRUD, Watch, Transaction
    POCTemplate.csproj
Tests/
  POCTemplate.Tests/    # Placeholder test project
compose.yml             # Docker Compose for local etcd

Key Concepts Demonstrated

Feature Description
Basic CRUD Put, Get, Delete a key-value pair
Watch Subscribe to changes on a key or key prefix
Transaction Atomically write multiple keys in a single request
Range watch Watch all keys under a “folder” prefix (e.g. animals/)

References