cs733

This is a key-value store written in GOlang. It listens on port 9000.

Features

• Keys can be strings and values can be any binary data.
• The key value pair can be assigned an expiry time after which it may not be available.
• It uses a priority queue internally to keep track of key value pairs to be deleted after expiry.

Instructions: How to run

1.Obtain a copy of the project using: go get github.com/swapniel99/keyvalstore

2.Change directory to keyvalstore : cd $GOPATH/src/github.com/swapniel99/keyvalstore

3.Run the test script using following commands: go test

Protocol specification

This specification describes the on-the-wire protocol, the exchange of commands and their results on a TCP connection. The client opens up a TCP connection Each command is a line in this format.The options are explained in the next section. The actual value data is on the next line.

1. Set: create the key-value pair, or update the value if it already exists.

   set [noreply]\r\n \r\n

   The server responds with:

   OK \r\n

   where version is a unique 64-bit number (in decimal format) assosciated with the key.

2. Get: Given a key, retrieve the corresponding key-value pair

   get \r\n

   The server responds with the following format (or one of the errors described later)

   VALUE \r\n \r\n

3. Get Meta: Retrieve value, version number and expiry time left

   getm \r\n

   The server responds with the following format (or one of the errors described below)

   VALUE \r\n \r\n

4. Compare and swap. This replaces the old value (corresponding to key) with the new value only if the version is still the same.

   cas [noreply]\r\n \r\n

   The server responds with the new version if successful (or one of the errors described late)

   OK \r\n

5. Delete key-value pair

   delete \r\n

   Server response (if successful)

   DELETED\r\n

Options:

key : an ascii text string (max 250 bytes) without spaces
numbytes: size of the value block, not including the trailing \r\n. It is in an ascii text format.
version: A 64-bit number generated by the server, in ascii text format.
exptime: An offset in seconds after which the value may not be available. 0 indicates no expiry at all.

Errors that can be returned.

“ERR_VERSION \r\n” (the value was not changed because of a version mismatch)
“ERRNOTFOUND\r\n” (the key doesn’t exist)
“ERRCMDERR\r\n” (the command line is not formatted correctly)
“ERR_INTERNAL\r\n

Thank you!