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While reading Comparing the Java Serialization Options I ran across the a cool google code project which has done an excellent job benchmarking a wide variety of serialization options for java.
I’ve had been researching the protobuf encoding format for a while and really liked it. But I did not really like the Java implementation that Google had published. It was kinda clunky to use and I saw several optimizations that could be used that were missing. Optimizations that could create huge performance wins when applied to the usage patterns of an enterprise messaging system like Apache ActiveMQ. So I created a new protobuf implementation in the ActiveMQ project.
Naturally, I was curious to see how the activemq protobuf implementation stacked up against similar technologies. So I grabbed the V1 benchmark source code and added our implementation to it. If you want to do the same, apply this patch.
Once I ran the benchmark and I was very pleased with the results. I’m including the performance graphs of our impl and standard protobuf and thrift for comparison.
As it turns out, our implementation looks awesome in the benchmark! How about that decoding speed!
It’s getting late here.. so I’ll have do a follow up post explaining how come we did so much better.
Wow, I can’t believe I missed it. Python lovers rejoice! Seems some good folks have created a python client for ActiveMQ which is using the very robust ActiveMQ C++ client.
And for those of you on Ubuntu, Dejan Bosanac has put together an excellent guide on how to build it on ubuntu.
Last weekend I got a little spare time an through together a small little library while should help with the problem of boring Java console applications on Windows.
It’s called Jansi and it provides support for using ANSI escape sequences in your Java console applications on Windows.
With ANSI escape sequences, you can fully control the the cursor positioning and the foreground and background color of the console text output. Here is quick example of what’s posssible:
So in my last post I was suggesting making it easier to include dependency checksums as part of a maven build. I decided that it should be simple enough to implement this as a Maven Plugin. For those of you interested, you can get the source to the new Checksum Plugin here.
The basic problem the plugin is trying to solve is that it is possible that central repositories get hacked and the artifacts/dependencies of our builds get replaced with
malicious versions. Right now we have no way to easily detect that
and we could potential create a release build of a project which
bundles one of those malicious dependencies. In practice this rarely
occurs, but it’s not out of the realm of possibilities.
Basically the plugin supports generating a checksum.txt file that is included as part of the project build. This file holds all the checksums for the dependencies (including the dependencies’ pom checksum). Generating/updating is induced via the use of a maven profile. This is only done when dependencies get updated.
In a normal build the plugin just validates the checksums of the downloaded dependencies against those stored in the checksum.txt file.
I wish I could move up the validation of the dependencies from their current maven life cycle locations, but it seems you can’t get the list of dependencies it gets moved up any more. Any maven mojo hackers have any work arounds for that?
For those of you who don’t know, Maven is an awesome build tool. It uses centralized repositories to share build artifacts. Right now there is a problem, where if a repository is hacked, malicious code could be injected into those artifacts and distributed by other builds. Lots of folks object to using maven solely due to this possibility. It’s a good thing that the maven teams seems to be working on fix those problems.
First off, I love the Maven Repository Security Proposal. I think that the ‘Specified Checksums’ idea is awesome. I think it needs to be made so easy to use that folks always use it. Right now it’s a little ugly because it makes the dependency declaration much more verbose. Plus it does not seem to cover transitive dependencies that are being used during the build, and I think that those checksums NEED to be included too.
I think that what would be better is if maven provided the tools to update the checksum information in the pom.
Lets say that a build for a module is setup in some strict mode where only artifacts with known checksums are allowed. If the pom is updated to add a new dependency, I think there should be some maven command which automatically adds the checksum for the new dependency (and transitive dependencies). Artifacts that are signed with a trusted key get added without prompting, and a confirmation prompt would be given for artifacts that are not GPG trusted.
So the question is why go through all that trouble? So that folks get a trusted source distribution (out of SCM or a signed tar ball), can do a build and have a high level of guarantee that the dependencies that are being used in the source build match what was intended by the developers of the source distribution. Furthermore, it will not matter if the transitive dependencies are signed and have keys in the end user’s keyring since all the checksums are include in the build.
Now, since there could be lots of dependencies in a build, due to the use of build plugins and transitive dependencies, it might be worth storing the checksum data in a file external to pom.xml, or at least in a different xml section from the dependencies declaration.
Things to think about: Having SNAPSHOT dependencies in the build could complicate things, as the build would be tied to a particular SNAPSHOT/checksum, but maybe that’s a good thing.