Kommander SimpleDB

A small replicated string key/value database built with .NET 10, Kommander 0.17.1, gRPC, and SQLite.

Each key is mapped by Kommander to one of eight Raft partitions. Every partition elects its own leader, so different keys may have different leaders. A node that receives a REST request for a partition it does not lead responds with 307 Temporary Redirect to that leader's REST endpoint. The 307 status preserves the method and body of PUT requests.

Writes are serialized as simpledb.put commands and committed through IRaft.ReplicateLogs. Every node applies committed and restored commands to its local SQLite values.db. Kommander's own durable log also uses SqliteWAL. Raft node-to-node traffic uses cleartext HTTP/2 gRPC on the local development ports.

Prerequisites

• .NET SDK 10
• curl for the examples

Run the cluster

./scripts/run-cluster.sh

The script publishes once, starts three nodes, labels each node's logs, and waits in the foreground. Press Ctrl+C to gracefully stop all three processes; any process that does not exit within five seconds is killed. Data persists under /tmp/simpledb-cluster by default.

Node	REST API	Raft gRPC
1	http://127.0.0.1:7001	127.0.0.1:7101
2	http://127.0.0.1:7002	127.0.0.1:7102
3	http://127.0.0.1:7003	127.0.0.1:7103

Override storage locations with SIMPLEDB_DATA_DIR and the publish directory with SIMPLEDB_PUBLISH_DIR. Remove the data directory for a clean cluster.

API

Use curl -L so requests follow leader redirects:

curl -L -X PUT http://127.0.0.1:7001/keys/name \
  -H 'Content-Type: application/json' \
  -d '{"value":"Ada"}'

curl -L http://127.0.0.1:7002/keys/name

PUT /keys/{key} accepts { "value": "a string" }. GET /keys/{key} returns the value or 404. /health reports whether that node has initialized its Kommander partitions.

For production, replace cleartext gRPC with TLS and node authentication, use externally reachable advertised addresses, and add snapshot/state-transfer handling before enabling elastic partition splits.