I was previously working with Kafka as my data source and found it very powerful but had a rather steep learning curve managed to get it partially working but had a few hitches here and there and don't feel comfortable maintaining it in production.
So decided to switch over to Rabbitmq since I am more familiar with it however I have run into a slight problem.
I am unable to find a Clojure Library for Apache Storm Spouting from Rabbitmq. Should I extend BaseRichSpout or can someone point me to a useful library.
There was no clear cut library to assist with this so I extended the
"BaseRichSpout" in java code, compiled to a jar file and imported it to clojure code.
There was quite a bit of diddling around because my Storm cluster was running backtype version i.e. older version of storm.
However this was the sample code I used.
Related
Today I tried to find an OrientDB binding for Clojure. I have found 2 libs: https://github.com/eduardoejp/clj-orient and https://github.com/eduardoejp/orientdb.clj .
I have tried to connect using clj-orient first, but it just throws an Exception
OIOException Cannot connect to any configured remote nodes: 127.0.0.1:2424 com.orientechnologies.orient.client.remote.OStorageRemote.createNetworkConnection (OStorageRemote.java:1413)
I have tried to connect through console, using the same credentials and connection was OK. It seems, that due to the fact of this lib is rather outdated, it tries to connect over outdated protocol. And it fails.
I did not tried orientdb.clj, cause it has no documentation at all. Maybe it is an option?
How clojure folks are connecting to the OrientDB nowadays?
Thanks for your help in advance!
If one of those libraries looks good to you in the terms of features implemented but a little bit out dated, then it makes sense to fork the library, upgrade what is missing and push it back to the open source community! :)
If you don't want to do that, then you can use OrientDB Java client in your Clojure code without problems.
I'm NOT the author of any of these libraries.
Doing a search of Clojars leads me to believe in 2021 your best option is whoneedszzz/orientdb-client
Orient probably needs to update their official docs on this, which still recommend the old eduardoejp version.
(It looks like someone else picked up support in 2017, but then dropped it again in 2019.)
I have been learning Clojure a bit recently. Is there such a thing in Clojure world as Scala-like worksheets, into which I can put any code and get it evaluated as soon as I save it? Or maybe there's a similar solution for Clojure?
I am now working with lein repl and, sadly, can't say it's the most usable tool ever.
In Lisp development in general (and Clojure in particular) the preferred programming style is what's usually dubbed interactive programming - the developer keeps an image of the app loaded at all times and interacts with it via a REPL. You can easily modify the loaded code on the fly and test changes immediately in the REPL (that's not easy at all with Scala - one has to resort to something like JRebel to do it). I find the Scala worksheets a pretty primitive solution in comparison...
The workflow that I follow in Clojure is:
I open nREPL.el in Emacs - this loads my lein2 project with all of its dependencies and gives me a REPL which I can use the try out stuff
I write some code in source code and load the changed functions (maybe by evaluating a top level form with C-M-x
Afterwards I'd press C-x C-z to jump back to the REPL and I try out the new code in it
I go back to step 2
Basically the Clojure REPL is much more powerful than the Scala REPL and I personally consider it hugely superior to the Scala IDE worksheets. Once you get used to the interactive incremental style of programming Lisp offers everything else starts to look strangely complex by comparison. I'm not familiar with Eclipse's CounterClockWise Clojure plugin, but I'm pretty sure it offers similar functionality to Emacs's nREPL.el.
You might want to take a look at the autoexpect plugin for Leiningen. Every time you save any file in the working directory, the plugin compiles and runs your code; as a bonus, it will evaluate any "expect" function calls which can serve as tests. This is very helpful for test driven development and is a nice compliment to working with the REPL as described in the other answer (I often use one or the other or both together depending on how many test cases I have in place).
I should note that running autoexpect is far faster than running "lein test" or "lein run" repeatedly, due to the startup cost of the JVM and Leiningen.
It sounds like what you are looking for is the Clojure Koan plugin. This a worksheet-style problem-solving exercise tool that watches your edits and provides instant feedback on the correctness of your work.
For actual development workflow I second the advice others here have provided on tooling and interactive environment setup, but since you specifically said you are learning Clojure, this can be a fun approach. There is also a web application called 4Clojure that you might have fun playing with.
However you will eventually (or right away) want to get a smooth and convenient development environment set up, and I haven't seen any mention so far of a few important tools. One person mentioned Nrepl. If you like Emacs, there's a slime/swank-like interaction mode that jacks into nrepl called nrepl.el that provides very nice integration between editing files and messing around in the repl. Similarly there is VimClojure, and you can find plugins for IntelliJ (LaClojure) and Eclipse (Counterclockwise) that are also popular and well-maintained.
Someone mentioned autoexpect. If you are looking for a good TDD setup, I would recommend midje. If you are using a 2.0 preview release of leiningen there are a few issues with the lazytest integration being in flux, and lazytest itself is or should be deprecated. But I prefer midje over expectations, personally, and these problems will surely be worked out in the 2.0 release of lein-midje. The stable version of lein-midje that works with the non-preview (1.x) leiningen has autotest-like functionality using lazytest.
As nobody has mentioned it, cursive is really nice these days, although I was sad to move back to a full blown IDE. You can easily do the same thing as Emacs with the built in repl, just move into the namespace that you are working with and synchronise every time you make changes. It's a really nice way of working.
Hey!! I'm looking for python bindings for opensg 1.8.. I haven't been able to find it. I have read somethin about pyopengs. Is it still available? I am working on linux platform (ubuntu). If anyone could direct me to it I would be grateful.
The homepage and source code is on google code: pyOpenSG Project
As one of the creators of pyOpenSG, I can tell you that it is definitely still alive and kicking. We use it in production software all the time. It has become so stable for us though that we don't often update the code base. The python binding generator that we use (py++) just keeps everything working between revisions.
I am working on Debian and I have this server we want to monitor.
The application is ours and there are around a hundred real-time counters we want to export for monitoring purposes, graphs and alarms.
I've been looking at the Debian way of doing this because we do use Debian packaging to install the app, and Debian uses snmpd daemon, based on net-snmp, to export SNMP.
So far every approach I've seen looks very complicated, from recompiling snmpd to load a dynamic library into it, and compiling a form of subagent that replicates what snmpd does.
While all of those options make me think I should go for something else than SNMP I don't want to give up that early and I was wondering if anybody has found a feasible implementation.
Ideally it should be coded in C or C++ as the app is in C++, but I'm open to wrappers or other kind of suggestions.
net-snmp supports both the smux and agentx agent extension protocols, allowing sub-agents to live in different processes. They also have a tutorial on writing AgentX subagents in C.
An often overlooked solution is Agent++ API, which to me looks pretty nice and is under the Apache license. As far as I understand, you can modify that agent to answer to your own MIBs.
That said, doing a subagent isn't such a bad choice. You start the standard unpatched snmpd (from net-snmp). Then you connect to it with your subagent, which only adds those OIDs you want it to add. The net-snmp kit for coding AgentX (as the protocol is called) sub-agents is not dead simple to use, but not very hard either. There is also a Perl module for sub-agent development: https://metacpan.org/pod/NetSNMP::agent
The traditional way to do this in linux is to use the net-snmp package. Make sure you write the MIB first. Everything is based on the MIB and changes to the MIB usually results in lots of changes in the code. Coding for net-snmp is not difficult and there is lots of documentation to get you started, eg: http://www.net-snmp.org/wiki/index.php/Tutorials#Coding_Tutorials
Have you tried net-snmp?
A colleague and I have spent a few years developing a really cool Matlab application, MDLcompress. Within Matlab, I can type "MDLcompress('filename.txt')" and it will tell me all sorts of really cool stuff about the contents of filename.txt. We'd like to allow other people to use MDLcompress without downloading the code, installing Matlab, etc. Ideally, we'd have a simple web page where they selected a file from their machine, it got uploaded to my workstation (which is already running tomcat for other purposes, if that makes things easier), kicked off a process along the lines of "matlab < MDLcompress.m filename.txt > results.txt" and then displayed results.txt in their browser or showed a link to let them download it.
Trouble is, my Matlab skills far exceed my web skills. Google has 100 generic tutorials, but nothing as simple as I want, at least not specific to Matlab.
Thanks in advance
If you are mostly proficient in MATLAB you can write web application in MATLAB with MATLAB Web Server
Edit:
Matlab Web Server is discontinued, so it is not for you if you use recent version of Matlab. May be this tutorial will help to create CGI module from Matlab code.
A possible way is to compile the matlab code into C,
and then make the C file into an apache module, and use an apache server.
I have no idea how complicated this is, but it may work.
Based on the tags, I assume you're trying to deploy to Tomcat or similar. The most straightforward way to do this is to use MATLAB Builder JA to create a Java wrapper for your code, then use the standard tools to deploy the Java as a web service.
If you can afford to lose some of Matlab's more powerful proprietary features, there are several open-source numerical computation engines that use syntax mostly compatible with that of Matlab. One of the most mature of these is GNU Octave.
There are several examples of online Octave interfaces. Octave Online is a new interface that supports a live prompt and an online editor. I am a member of the team developing Octave Online. You can find more examples of online Octave interfaces on the Octave wiki. The Octave mailing list is a good resource for prior online Octave projects.
We have developed a toolbox called Modelit Webserver Toolbox that should allow you to do this. We use this ourselves to run a Routing algorithm implemented in Matlab for an online route planner (the link is on our website). You can use the toolbox in conjunction with Tomcat and Matlab (2006b and up) or a compiled Matlab executable. The toolbox also provides a mechanism to run several jobs in parallel.