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RoachJS - CockroachDB Driver

Note: RoachJS will only work against old versions of CockroachDB that expose the key-value API.

To interact with newer versions you can use a library that works with Postgres. For more, please see the CockroachDB docs.

NPM

Build Status

Introduction

This client is a port from the original Golang client. Internally it's is more or less the same, but this driver provides a friendlier javascript interface.

Installation

$ npm install roachjs

Documentation

Examples

Initiating a client

var Roach = require('roachjs')

var client = new Roach({
    uri: 'https://localhost:8080'
})

module.exports = client

Basic client usage I

client.get("sample_key", function(err, value, res) {
    if(err) throw err

    client.put("other_key", value, function(err, res) {
        if(err) {
            // Failed
        }
        else {
            // Sucess
        }
    })
})

Advanced client usage I (Prepare & Flush)

// You should prepare your queries and send them in a single batch
// For optimal performance
var c = client.prepare()

// This callback will be the first to be executed
c.get("sample_key", function(err, value, res) {
    if(err) throw err

    // Do something...
})

c.get("sample_key2", function(err, value, res) {
    if(err) throw err

    // Do something...
})

c.put("some_key", "some_value", function(err) {
    if(err) throw err

    // Do something
})

// The flush callback is the last one to be called
c.flush(function(err, res) {
    if(err) throw err

    console.log('Sucessfuly flushed %d queries.', res.responses.length)
})

Advanced client usage II (Transactions)

var opts = {
    name: "transaction example",
}

var errNoApples = new Error('Insufficient apples!')

var transaction = function(txn, commit, abort) {
    txn.get("applesInStock", function(err, value, res) {
        if(err || applesInStock.err) {
                return abort(err)
            }

            var dispatch = 5
            var inStock = parseInt(applesInStock.value)

            if(inStock < dispatch) {
                return abort(errNoApples)
        }

        // Upgrade for a prepared client
        txn = txn.prepare()

        txn.increment("applesInStock", -dispatch)
        txn.increment("applesInRoute", +dispatch)

        // Commit automatically flushes
        commit()
    })
}

client.runTransaction(opts, transaction, function(err, res) {
    if(err === errNoApples) {
        // Alert user there are no more apples...
    }
    else if(err) {
        // Transaction failed...
    }
    else {
        // Transaction commited...
    }
})

Interface

new Client(opts)

Returns a new roachjs client with options.

Parameters
name type description
opts object see
Client options
opt description default
uri uri to the cockroach http endpoint https://localhost:8080/
host host or ip to the cockroach http endpoint localhost
port port to the cockroach http endpoint 8080
ssl connect throught https true
user user to run the requests with root
retry retry requests when cockroach responds with a busy signal true
http http module to use require('https')
agent http agent to use on the requests (read more) new http.Agent()
clock clock module to use (read more) internal clock module
Methods
method
get
put
conditionalPut
contains
increment
scan
delete
deleteRange
prepare
runTransaction

client.get(key, callback)

Gets a single entry from the datastore, specified by key.

Parameters
name type description
key string
callback callback function(err, value, res) {}
Callback
name type description
err Error()
value Buffer
res object see
Example
client.get("key", function(err, value, res) {})

client.put(key, value, callback)

Puts a value in the datastore in the specified key. Ideally you should send in buffers, but you can pass a string, preferably an utf-8 encoded string.

Parameters
name type description
key string
value Buffer, string
callback callback function(err, res) {}
Callback
name type description
err Error()
res object see
Example
client.put("key", "value", function(err, res) {})

client.conditionalPut(key, value, ifValue, callback)

ConditionalPut sets the value for a key if the existing value matches the ifValue. Specifying an empty or null ifValue means the entry must not yet exist.

Parameters
name type description
key string
value Buffer, string
ifValue Buffer, string, null use null to put if entry doens't exists
callback callback function(err, res) {}
Callback
name type description
err Error()
actualValue Buffer If conditional put fails this value is set
res object see
Example
client.conditionalPut("status", "running", "stopped", function(err, actualValue, res) {})
client.conditionalPut("status", "new", null, function(err, actualValue, res) {})

client.contains(key, callback)

Contains determines if a key exists in the datastore.

Parameters
name type description
key string
callback callback function(err, exists, res) {}
Callback
name type description
err Error()
exists boolean
res object see
Example
client.contains("john", function(err, exists, res) {
    if(exists === true) {
        // john exists in the datastore
    }
})

client.increment(key, increment, callback)

Increment increments the value at the specified key by some increment value. Once called for a key, Put & Get will return errors; only Increment will continue to be a valid command. The value must be deleted before it can be reset using Put.

Parameters
name type description
key string
increment integer
callback callback function(err, newValue, res) {}
Callback
name type description
err Error()
newValue integer the new value for this counter, after the increment operation
res object see
Example
client.increment("counter", 5, function(err, newValue, res) {
    console.log('counter current value is', newValue)
})

client.scan(start_key, end_key, limit, callback)

Scan the datastore for keys in the range of the start_key and end_key, limiting the result by limit.

Parameters
name type description
key string
start_key string
end_key string
limit integer
callback callback function(err, rows, res) {}
Callback
name type description
err Error()
rows array
res object see
Example
client.scan("a", "Z", 100, function(err, rows, res) {
    for(row as rows) {
        console.log(row)
    }
})

client.delete(key, callback)

Delete an entry from the datastore specified by key.

Parameters
name type description
key string
callback callback function(err, res) {}
Callback
name type description
err Error()
res object see
Example
client.delete("key", function(err, res) {})

client.deleteRange(start_key, end_key, limit, callback)

Delete all keys found in a range, from start_key to end_key, limited by limit.

Parameters
name type description
key string
start_key string
end_key string
limit integer
callback callback function(err, deleted, res) {}
Callback
name type description
err Error()
deleted integer number of entries deleted
res object see
Example
client.deleteRange("a", "Z", 100, function(err, deleted, res) {
    console.log('deleted %d entries', deleted)
})

client.prepare()

Return you a new prepared client. It has all the methods from the original client. Read Advanced client usage II to understand how to use this client. You should always use this client when sending in multiple queries, this will batch them together in a single request.

Methods
method description
flush Flush the prepared queries
Example
var c = client.prepare()

c.get("key", function(err, value, res) {
    // Do something...
})

c.get("key2", function(err, value, res) {
    // Do something...
})

c.put("key3", "value", function(err, res) {
    // Do something...
})

c.flush()

client.flush(callback)

Flush the prepared queries buffer, and send it as a batch request.

Parameters
name type description
callback callback optional
Callback
name type description
err Error() batch request failed
res object see
Example
client.flush(function(err, res) {
    if(err) {
        // Flush failed..
    }
    else {
        console.log('flushed %d queries.', res.responses.length)
    }
})
Returns

Returns an response object.

property type description
err Error() is null if no error was returned
value string, number, boolean general response value
res object see

client.runTransaction(opts, transaction, callback)

RunTransaction executes a retryable transaction function in the context of a distributed transaction. The transaction is automatically aborted if retryable function returns any error aside from recoverable internal errors, and is automatically committed otherwise. retryable should have no side effects which could cause problems in the event it must be run more than once. The opts contains transaction settings.

Parameters
name type description
opts object options
transacation retryable function function(txn, commit, abort) {}
callback callback function(err, res) {}
Transaction options
opt description default
name transaction name for debugging ""
isolation 0
Callback
name type description
err Error() if transaction fails
res object see

Extra

Response properties

The res argument contains the full database response, each database command can contain a different set of properties. This document will try to state some of the possible properties.

Properties
property type description
timestamp integer timestamp of the returned entry
wall_time integer timestamp of when the read or write operation was performed

Transaction function

The transaction function is an retryable function, it may be executed more than once. This function should never forget to call commit or abort. Throwing an error inside this function also aborts the transaction.

Arguments
name type description
txn Prepared client this client is the same as client.prepare(), you can flush yourself if you don't wan't to commit yet.
commit callback to try to commit transaction
abort callback to abort transaction
  • abort() accepts an optional Error. This error will be passed to the .runTransaction callback.
Example
var transaction = function(txn, commit, abort) {
    txn = txn.prepare()

    for(var i = 0; i < 100; i++) {
        var key = i.toString()

        txn.put(key, "hello")
    }

    // Commit automatically flushes
    // the prepared transaction.
    commit()
}

Compiling .proto files

Cockroachdb's protocol buffer files are mantained at a repository called cockroachdb/cockroach-proto, this is maintained as a subtree in this library, in case you need to manually update or change them, follow this steps.

If you want to sync them with the latest proto files

You will need to update the folder cockroach-proto with the latest content of the cockroachdb/cockroach-proto repository, you could do this with:

$ git subtree pull -P cockroach-proto [email protected]:cockroachdb/cockroach-proto.git master --squash
  • Notice: I'm not sure if this is a good pattern, just be sure to update the folder contents.
Recompile the .proto files

Run the following npm script to compile the .proto files to javascript, it will automatically place the files in the lib folder.

$ npm run build-proto

Custom clock module

You may wan't to use a custom clock module in some cases, you can pass it through the clock option, when instantiating a new Client. Your clock module should have a now method, and this method should return the current timestamp in nanoseconds, here is an example:

var clockModule = module.exports = {
    now: function TimestampNanoseconds() {
        // Should return the current timestamp in nanoseconds
        return ...;
    }
}

var client = new Client({
    clock: clockModule
})

Maintainers