This project implements distributed grep functionality which enables querying of distributed log files on multiple machines, from any one of those machines.

A simple Client-server architecture has been used. All the machines from which log files have to be queried must have the server (called grep-server) running. A client (called grep-client) takes grep queries from user and displays back matching lines. The client additionally requires a configuration file which stipulates the addresses of the servers and local logfile path in the machines.

The processing paradigm is as follows. The client takes the grep query from user and spawns multiple threads (each talking to one server). Each thread relays the query to its server. In the server, the grep query is executed locally and the matching lines are relayed back to the client thread. The client thread then prints this matching line.

Multithreaded client and multithreaded server not only ensure faster execution due to paralellization, but also add fault tolerance. The fault tolerance guarantee of the system is that it fetches answers from all machines that have not failed.

• Java 7
• Maven

grep-server has to be run in all machines containing required log files. The following are the steps to run server in one machine :

1. ssh into the vm machine : Eg - ssh <NETID>@fa15-cs425-gNN-XX.cs.illinois.edu
2. Type git clone https://gitlab-beta.engr.illinois.edu/cs425-agupta80-pmazmdr2/mp1-distributed-logging.git
3. cd into the project root directory
4. run mvn -DskipTests package. You should see build success.
5. Type cd ./scripts/ && ./run_server <PORT_NUMBER_XX>

The configuration file has 3 lines : serverAddress, serverPort and logFilePath. This file stores the server address (fa15-cs425-gNN-XX.cs.illinois.edu), server port (same as <PORT_NUMBER_XX> in step 1.5) and filepath of the log file for all the machines. Refer to ./src/main/resources/config.properties for format details.

Once the grep-servers are all running and configuration file is properly set, validation can be done by running unittest. This can be done by running mvn test in project root directory.

grep-client takes grep query and grep matching control options from user. The configuration file path (populated in step 2) and the grep query string are required arguments, other switches are optional. The help switch shows usage instructions.

1. cd ./scripts/
2. run_client -help