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.
Directories ¶
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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. |
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