nats-server

README

gnatsd

A High Performance NATS Server written in Go.

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'

http://localhost:8222/varz reports various general statistics.

{
  "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
}

http://localhost:8222/connz 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. http://localhost:8222/connz?limit=1&offset=1. You can also report detailed subscription information on a per connection basis using subs=1, e.g. http://localhost:8222/connz?limit=1&offset=1&subs=1.

{
  "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_size": 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_size": 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"
      ]
    }
  ]
}

http://localhost:8222/routez 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. http://localhost:8222/routez?subs=1

{
  "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
    }
  ]
}

http://localhost:8222/subscriptionsz reports detailed information about the current subscriptions and the routing data structure.

{
  "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

// 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
• Java
• Java - Spring
• Node.js
• Ruby
• Lua
• PHP
• Python
• Scala
• Haskell

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.