Internet of Things - Reactive and Asynchronous with Vert.x

I have to admit … be­fore join­ing Red Hat I didn’t know about the Eclipse Vert.x project but it took me few days to fall in love with it!

For the other de­vel­op­ers who don’t know what Vert.x is, the best de­f­i­n­i­tion is …

… a toolkit to build dis­trib­uted and re­ac­tive sys­tems on top of the JVM using an asyn­chro­nous non block­ing de­vel­op­ment model

The first big thing is re­lated to de­velop a re­ac­tive sys­tem using Vert.x which means :

• Re­spon­sive : the sys­tem re­sponds in an ac­cept­able time;
• Elas­tic : the sys­tem can scale up and scale down;
• Re­silient : the sys­tem is de­signed to han­dle fail­ures grace­fully;
• Asyn­chro­nous : the in­ter­ac­tion with the sys­tem is achieved using asyn­chro­nous mes­sages;

The other big thing is re­lated to use an asyn­chro­nous non block­ing de­vel­op­ment model which doesn’t mean to be multi-​threading but thanks to the non block­ing I/O (i.e. for han­dling net­work, file sys­tem, …) and call­backs sys­tem, it’s pos­si­ble to han­dle a huge num­bers of events per sec­ond using a sin­gle thread (aka “event loop”).

You can find a lot of ma­te­r­ial on the of­fi­cial web site in order to bet­ter un­der­stand what Vert.x is and all its main fea­tures; it’s not my ob­jec­tive to ex­plain it in this very short ar­ti­cle that is mostly … you guess … mes­sag­ing and IoT ori­ented :-)

In my opin­ion, all the above fea­tures make Vert.x a great toolkit for build­ing In­ter­net of Things ap­pli­ca­tions where being re­ac­tive and asyn­chro­nous is a “must” in order to han­dle mil­lions of con­nec­tions from de­vices and all the mes­sages in­gested from them.

Vert.x and the Internet of Things

As a toolkit, so made of dif­fer­ent com­po­nents, what are the ones pro­vided by Vert.x and use­ful to IoT?

Start­ing from the Vert.x Core com­po­nent, there is sup­port for both ver­sions of HTTP pro­to­col so 1.1 and 2.0 in order to de­velop an HTTP server which can ex­pose a REST­ful API to the de­vices. Today , a lot of web and mo­bile de­vel­op­ers pre­fer to use this pro­to­col for build­ing their IoT so­lu­tion lever­ag­ing on the deep knowl­edge they have about the HTTP pro­to­col.

Re­gard­ing more IoT ori­ented pro­to­cols, there is the Vert.x MQTT server com­po­nent which doesn’t pro­vide a full bro­ker but ex­poses an API that a de­vel­oper can use in order to han­dle in­com­ing con­nec­tions and mes­sages from re­mote MQTT clients and then build­ing the busi­ness logic on top of it, so for ex­am­ple de­vel­op­ing a real bro­ker or ex­e­cut­ing pro­to­col trans­la­tion (i.e. to/from plain TCP,to/from the Vert.x Event Bus,to/from HTTP,to/from AMQP and so on). The API raises all events re­lated to the con­nec­tion re­quest from a re­mote MQTT client and all sub­se­quent in­com­ing mes­sages; at same time, the API pro­vides the way to reply to the re­mote end­point. The de­vel­oper doesn’t need to know how MQTT works on the wire in terms of en­cod­ing/de­cod­ing mes­sages.

Re­lated to the AMQP 1.0 pro­to­col there are the Vert.x Pro­ton and the AMQP bridge com­po­nents. The first one pro­vides a thin wrap­per around the Apache Qpid Pro­ton en­gine and can be used for in­ter­act­ing with AMQP based mes­sag­ing sys­tems as clients (sender and re­ceiver) but even de­vel­op­ing a server. The last one pro­vides a bridge be­tween the pro­to­col and the Vert.x Event Bus mostly used for com­mu­ni­ca­tion be­tween de­ployed Vert.x ver­ti­cles. Thanks to this bridge, ver­ti­cles can in­ter­act with AMQP com­po­nents in a sim­ple way.

Last but not least, the Vert.x Kafka client com­po­nent which pro­vides ac­cess to Apache Kafka for send­ing and con­sum­ing mes­sages from top­ics and re­lated par­ti­tions. A lot of IoT sce­nar­ios lever­age on Apache Kafka in order to have an in­ges­tion sys­tem ca­pa­ble of han­dling mil­lion mes­sages per sec­ond.

Conclusion

The cur­rent Vert.x code base pro­vides quite in­ter­est­ing com­po­nents for de­vel­op­ing IoT so­lu­tions which are al­ready avail­able in the cur­rent 3.3.3 ver­sion (see Vert.x Pro­ton and AMQP bridge) and that will be avail­able soon in the fu­ture 3.4.0 ver­sion (see MQTT server and Kafka client). Of course, you don’t need to wait for their of­fi­cial re­lease be­cause, even if under de­vel­op­ment, you can al­ready adopt these com­po­nents and pro­vide your feed­back to the com­mu­nity.

This ecosys­tem will grow in the fu­ture and Vert.x will be a lead­ing actor in the IoT ap­pli­ca­tions world based on a mi­croser­vices ar­chi­tec­ture!