Consensus

Simple web application that stores String key/value pairs and can be distributed to multiple servers.

Uses Two-phase commit protocol for replicating data.

Examples

Run

./gradlew clean build uberjar

to build project.

Start instance java -jar pathToProject/build/libs/consensus.jar 7000 7001 7002 where 7000 is port for this instance and ports 7001 7002 of other instances. The number of instances is not limited.

GET curl localhost:7000/example where example is key of key/pair entry.

PUT curl -XPUT -H "Content-Type: application/json" -d '{"value":"newvalue"}' localhost:8080/bolobolo where bolobolo is the key and newvalue the value of new entry.

Todo

Delete functionality.

Test cases

Commit

Run

./scripts/start_cluster.sh

that starts three instances that are configured to have each others as neighbors. Run

curl -XPUT -H "Content-Type: application/json" -d '{"value":"value"}' localhost:8080/key

and new entry will be replicated to other nodes. Check with curl or go to http://localhost:8082/key.

Abort

Run

./scripts/aborting_cluster.sh

that starts two instances that are configured to have third, non existant neighbor. Run

curl -XPUT -H "Content-Type: application/json" -d '{"value":"value"}' localhost:8080/key