# gnatsd

[![License][License-Image]][License-Url] [![Build][Build-Status-Image]][Build-Status-Url] [![Release][Release-Image]][Release-Url] [![Coverage][Coverage-Image]][Coverage-Url]

A High Performance [NATS](https://nats.io) Server written in [Go.](http://golang.org)

## Usage

gnatsd accepts command line arguments to control its behavior. An example  configuration file is listed below. Note that
command line arguments will override those items in the configuration file.


```
Server Options:
    -a, --addr HOST                  Bind to HOST address (default: 0.0.0.0)
    -p, --port PORT                  Use PORT for clients (default: 4222)
    -P, --pid FILE                   File to store PID
    -m, --http_port PORT             Use HTTP PORT for monitoring
    -c, --config FILE                Configuration File

Logging Options:
    -l, --log FILE                   File to redirect log output
    -T, --logtime                    Timestamp log entries (default: true)
    -s, --syslog                     Enable syslog as log method.
    -r, --remote_syslog              Syslog server addr (udp://localhost:514).
    -D, --debug                      Enable debugging output
    -V, --trace                      Trace the raw protocol
    -DV                              Debug and Trace

Authorization Options:
        --user user                  User required for connections
        --pass password              Password required for connections

Cluster Options:
        --routes [rurl-1, rurl-2]    Routes to solicit and connect

Common Options:
    -h, --help                       Show this message
    -v, --version                    Show version
```

## Sample Configuration

```

port: 4242      # port to listen for client connections
net: apcera.me  # net interface to listen

http_port: 8222 # HTTP monitoring port

# Authorization for client connections
authorization {
  user:     derek
  password: T0pS3cr3t
  timeout:  1
}

# Cluster definition

cluster {

  host: '127.0.0.1'  # host/net interface
  port: 4244         # port for inbound route connections

  # Authorization for route connections
  authorization {
    user: route_user
    password: T0pS3cr3tT00!
    timeout: 0.5
  }

  # Routes are actively solicited and connected to from this server.
  # Other servers can connect to us if they supply the correct credentials
  # in their routes definitions from above.

  routes = [
    nats-route://user1:pass1@127.0.0.1:4245
    nats-route://user2:pass2@127.0.0.1:4246
  ]
}

# logging options
debug:   false
trace:   true
logtime: false
log_file: "/tmp/gnatsd.log"

# pid file
pid_file: "/tmp/gnatsd.pid"

# Some system overides

# max_connections
max_connections: 100

# maximum protocol control line
max_control_line: 512

# maximum payload
max_payload: 65536

# slow consumer threshold
max_pending_size: 10000000

```

## Monitoring

If the monitoring port is enabled, the server will run a lightweight http server on that port that has several endpoints [/varz, /connz, /routez, /subscriptionsz]. All endpoints return a JSON object.

To test, run '``go run gnatsd.go -m 8222``'

<a href="http://localhost:8222/varz" target="_blank">http://localhost:8222/varz</a> reports various general statistics.

```json
{
  "server_id": "ec933edcd2bd86bcf71d555fc8b4fb2c",
  "version": "0.6.6",
  "go": "go1.5.0",
  "host": "0.0.0.0",
  "port": 4222,
  "auth_required": false,
  "ssl_required": false,
  "max_payload": 1048576,
  "max_connections": 65536,
  "ping_interval": 120000000000,
  "ping_max": 2,
  "http_port": 8222,
  "ssl_timeout": 0.5,
  "max_control_line": 1024,
  "max_pending_size": 10485760,
  "max_payload": 1048576,
  "start": "2015-07-14T13:29:26.426805508-07:00",
  "now": "2015-07-14T13:30:59.349179963-07:00",
  "uptime": "1m33s",
  "mem": 8445952,
  "cores": 4,
  "cpu": 0,
  "connections": 39,
  "routes": 0,
  "remotes": 0,
  "in_msgs": 100000,
  "out_msgs": 100000,
  "in_bytes": 1600000,
  "out_bytes": 1600000,
  "slow_consumers": 0
}
```

<a href="http://localhost:8222/connz" target="_blank">http://localhost:8222/connz</a> reports more detailed information on current connections. It uses a paging mechanism which defaults to 1024 connections.
You can control these via url arguments (limit and offset), e.g. <a href="http://localhost:8222/connz?limit=1&offset=1" target="_blank">http://localhost:8222/connz?limit=1&offset=1</a>.
You can also report detailed subscription information on a per connection basis using subs=1, e.g. <a href="http://localhost:8222/connz?limit=1&offset=1&subs=1" target="_blank">http://localhost:8222/connz?limit=1&offset=1&subs=1</a>.

```json
{
  "now": "2015-07-14T13:30:59.349179963-07:00",
  "num_connections": 2,
  "offset": 0,
  "limit": 1024,
  "connections": [
    {
      "cid": 571,
      "ip": "127.0.0.1",
      "port": 61572,
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "lang": "go",
      "version": "1.0.9",
      "subscriptions_list": [
        "hello.world"
      ]
    },
    {
      "cid": 574,
      "ip": "127.0.0.1",
      "port": 61577,
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "lang": "ruby",
      "version": "0.5.0",
      "subscriptions_list": [
        "hello.world"
      ]
    }
  ]
}
```


<a href="http://localhost:8222/routez" target="_blank">http://localhost:8222/routez</a> reports information on active routes for a cluster. Routes are expected to be low, so there is no paging mechanism currently with this endpoint. It does support the subs arg line /connz, e.g. <a href="http://localhost:8222/routez?subs=1" target="_blank">http://localhost:8222/routez?subs=1</a>

```json
{
  "now": "2015-07-14T13:30:59.349179963-07:00",
  "num_routes": 1,
  "routes": [
    {
      "rid": 1,
      "remote_id": "de475c0041418afc799bccf0fdd61b47",
      "did_solicit": true,
      "ip": "127.0.0.1",
      "port": 61791,
      "pending_size": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 0
    }
  ]
}
```

<a href="http://localhost:8222/subscriptionsz" target="_blank">http://localhost:8222/subscriptionsz</a> reports detailed information about the current subscriptions and the routing data structure.

```json
{
  "num_subscriptions": 3,
  "num_cache": 0,
  "num_inserts": 572,
  "num_removes": 569,
  "num_matches": 200000,
  "cache_hit_rate": 0.99999,
  "max_fanout": 0,
  "avg_fanout": 0,
  "stats_time": "2015-07-14T12:55:25.564818051-07:00"
}
```

Monitoring endpoints support JSONP for CORS so you can easily create single page
web applications for monitoring. Simply pass `callback` query parameter to any
endpoint. For example; `http://localhost:8222/connz?callback=cb`

```javascript
// JQuery example

$.getJSON('http://localhost:8222/connz?callback=?', function(data) {
  console.log(data);
});

```

## Building

This code currently requires at _least_ version 1.1 of Go, but we encourage
the use of the latest stable release.  We will be moving to requiring at _least_ 1.4
in the near future. Go is still young and improving
rapidly, new releases provide performance improvements and fixes.  Information
on installation, including pre-built binaries, is available at
<http://golang.org/doc/install>.  Stable branches of operating system
packagers provided by your OS vendor may not be sufficient.

Run `go version` to see the version of Go which you have installed.

Run `go build` inside the directory to build.

Run `go test ./...` to run the unit regression tests.

A successful build run produces no messages and creates an executable called
`gnatsd` in this directory.  You can invoke that binary, with no options and
no configuration file, to start a server with acceptable standalone defaults
(no authentication, no clustering).

Run `go help` for more guidance, and visit <http://golang.org/> for tutorials,
presentations, references and more.


## Client libraries

There are several client language bindings for NATS. For a complete and updated list, please visit <https://nats.io>.
- [Go](https://github.com/nats-io/nats)
- [Java](https://github.com/tyagihas/java_nats)
- [Java - Spring](https://github.com/mheath/jnats)
- [Node.js](https://github.com/nats-io/node-nats)
- [Ruby](https://github.com/nats-io/ruby-nats)
- [Lua](https://github.com/DawnAngel/lua-nats)
- [PHP](https://github.com/repejota/phpnats)
- [Python](https://github.com/mcuadros/pynats)
- [Scala](https://github.com/tyagihas/scala_nats/)
- [Haskell](https://github.com/ondrap/nats-queue)


## License

(The MIT License)

Copyright (c) 2012-2015 Apcera Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
IN THE SOFTWARE.

[License-Url]: http://opensource.org/licenses/MIT
[License-Image]: https://img.shields.io/npm/l/express.svg
[Build-Status-Url]: http://travis-ci.org/nats-io/gnatsd
[Build-Status-Image]: https://travis-ci.org/nats-io/gnatsd.svg?branch=master
[Release-Url]: https://github.com/nats-io/gnatsd/releases/tag/v0.6.8
[Release-image]: http://img.shields.io/badge/release-v0.6.8-1eb0fc.svg
[Coverage-Url]: https://coveralls.io/r/nats-io/gnatsd?branch=master
[Coverage-image]: https://img.shields.io/coveralls/nats-io/gnatsd.svg