Documentation ¶
Overview ¶
Package volantmq is a high performance MQTT broker and client library that aims to be fully compliant with MQTT 3.1 and 3.1.1 specs.
The primary package that's of interest is package service. It provides the MQTT Server and Client services in a library form.
MQTT is a Client Server publish/subscribe messaging transport protocol. It is light weight, open, simple, and designed so as to be easy to implement. These characteristics make it ideal for use in many situations, including constrained environments such as for communication in Machine to Machine (M2M) and Internet of Things (IoT) contexts where a small code footprint is required and/or network bandwidth is at a premium. The protocol runs over TCP/IP, or over other network protocols that provide ordered, lossless, bi-directional connections. Its features include: - Use of the publish/subscribe message pattern which provides one-to-many message distribution and decoupling of applications. - A messaging transport that is agnostic to the content of the payload. - Three qualities of service for message delivery: - "At most once", where messages are delivered according to the best efforts of the operating environment. Message loss can occur. This level could be used, for example, with ambient sensor data where it does not matter if an individual reading is lost as the next one will be published soon after. - "At least once", where messages are assured to arrive but duplicates can occur. - "Exactly once", where message are assured to arrive exactly once. This level could be used, for example, with billing systems where duplicate or lost messages could lead to incorrect charges being applied. - A small transport overhead and protocol exchanges minimized to reduce network traffic. - A mechanism to notify interested parties when an abnormal disconnection occurs.
Current performance benchmark of VolantMQ, running all publishers, subscribers and broker on a single 4-core (2.8Ghz i7) MacBook Pro, is able to achieve:
- over 400,000 MPS in a 1:1 single publisher and single producer configuration
- over 450,000 MPS in a 20:1 fan-in configuration
- over 750,000 MPS in a 1:20 fan-out configuration
- over 700,000 MPS in a full mesh configuration with 20 clients
In addition, VolantMQ has been tested with the following client libraries and it _seems_ to work:
- libmosquitto 1.3.5 (C)
- Tested with the bundled test programs msgsps_pub and msgsps_sub
- Paho MQTT Conformance/Interoperability Testing Suite (Python)
- Tested with all 10 test cases.
- Paho Go Client Library (Go)
- Tested with one of the tests in the library, in fact, that tests is now part of the tests for VolantMQ
- Paho C Client library (C)
- Tested with most of the test cases and failed the same ones as the conformance test because the features are not yet implemented.
- Actually I think there's a bug in the test suite as it calls the PUBLISH handler function for non-PUBLISH messages.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrInvalidNodeName node name does not follow requirements ErrInvalidNodeName = errors.New("node name is invalid") )
Functions ¶
This section is empty.
Types ¶
type Server ¶
type Server interface { // ListenAndServe configures transport according to provided config // This is non blocking function. It returns nil if listener started // or error if any happened during configuration. // Transport status reported over TransportStatus callback in server configuration ListenAndServe(interface{}) error // Close terminates the server by shutting down all the client connections and closing // configured listeners. It does full clean up of the resources and Close() error }
Server server API
func NewServer ¶
func NewServer(config *ServerConfig) (Server, error)
NewServer allocate server object
type ServerConfig ¶
type ServerConfig struct { // Configuration of persistence provider Persistence persistence.Provider // OnDuplicate notify if there is attempt connect client with id that already exists and active // If not not set than defaults to mock function OnDuplicate func(string, bool) // TransportStatus user provided callback to track transport status // If not set than defaults to mock function TransportStatus func(id string, status string) // ConnectTimeout The number of seconds to wait for the CONNACK message before disconnecting. // If not set then default to 2 seconds. ConnectTimeout int // KeepAlive The number of seconds to keep the connection live if there's no data. // If not set then defaults to 5 minutes. KeepAlive int // SystreeUpdateInterval SystreeUpdateInterval time.Duration // NodeName NodeName string // Authenticator is the authenticator used to check username and password sent // in the CONNECT message. If not set then defaults to "mockSuccess". Authenticators string // AllowedVersions what protocol version server will handle // If not set than defaults to 0x3 and 0x04 AllowedVersions map[packet.ProtocolVersion]bool // MaxPacketSize MaxPacketSize uint32 // AllowOverlappingSubscriptions tells server how to handle overlapping subscriptions from within one client // if true server will send only one publish with max subscribed QoS even there are n subscriptions // if false server will send as many publishes as amount of subscriptions matching publish topic exists // If not set than default is false AllowOverlappingSubscriptions bool // RewriteNodeName RewriteNodeName bool // OfflineQoS0 tell server to either persist (true) or not persist (false) QoS 0 messages for non-clean sessions // If not set than default is false OfflineQoS0 bool // AllowDuplicates Either allow or deny replacing of existing session if there new client with same clientID // If not set than default is false AllowDuplicates bool // WithSystree WithSystree bool // ForceKeepAlive ForceKeepAlive bool }
ServerConfig configuration of the MQTT server
func NewServerConfig ¶
func NewServerConfig() *ServerConfig
NewServerConfig with default values. It's highly recommended to use that function to allocate config rather than directly ServerConfig structure
Directories ¶
Path | Synopsis |
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examples
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Package topics deals with MQTT topic names, topic filters and subscriptions.
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Package topics deals with MQTT topic names, topic filters and subscriptions. |