Enabling Cassandra logback debugging

In our pursuit for 100% centralized logging, I found myself recently settingup logback-gelf with Cassandra working. The intention was to point Cassandra’s logback config at our graylog2 install, but I had a mis-step somewhere during setup.

After beating my head against a wall for a while, I got in touch with DataStax support to see if they could advise me how to enable logback debugging in Cassandra. They obliged, I quickly found an error message pointing me in the right direction, and we are today happily using logback+GELF with our Cassandra install.

For anyone else wishing to enable logback debug mode, add the following line to your /etc/dse/cassandra/cassandra-env.sh:

JVM_OPTS="$JVM_OPTS -Dlogback.debug=true"

After that, debug output can be found in /var/log/cassandra/output.log.

Progress update on python-gotalk

As covered in a previous post, I’ve been tinkering with a Pythonimplementation of the fledgling Gotalk. Since this has been fun to play with, I figured it’d be worth sharing where python-gotalk is, and what has happened with it in the last two weeks.

Upstream gotalk progress

Rasmus has created a new protocol v1 branch in the Gotalk repo, where all of the new hotness is landing. A few hilights:

• Request IDs have grown from three bytes to four in response to requests for more potential permutations.
• A new ProtocolError message type was added. This is sent when a peer doesn’t understand the protocol version specified by the sender. While I haven’t seen any specifics on how potential downgrades may work, this could conceivably be used to handle that in the future (maybe?). It is not clear if gotalk is striving for any kinds of backwards compatibility between protocol versions, so that’ll be something to watch.
• The Go and JS example client/servers have progressed quite a bit.

python-gotalk updates

At this point in time, we should be current with the gotalk v1 branch wire format (as of the night of Feb 6). I haven’t started on any socket/state tracking stuff, and probably won’t until v1 is mostly solidified.

However, I’ve thought about keeping python-gotalk focused on just the message marshalling/unmarshalling. The socket/state tracking code will differ quite a bit depending on whether you are using Twisted, asyncio, Tornado, etc. It’d also mean that python-gotalk could avoid all external dependencies.

We’ll continue tracking the Gotalk v1 branch and see how it goes!

Progress update on python-gotalk

As covered in a previous post, I’ve been tinkering with a Pythonimplementation of the fledgling Gotalk. Since this has been fun to play with, I figured it’d be worth sharing where python-gotalk is, and what has happened with it in the last two weeks.

Upstream gotalk progress

Rasmus has created a new protocol v1 branch in the Gotalk repo, where all of the new hotness is landing. A few hilights:

• Request IDs have grown from three bytes to four in response to requests for more potential permutations.
• A new ProtocolError message type was added. This is sent when a peer doesn’t understand the protocol version specified by the sender. While I haven’t seen any specifics on how potential downgrades may work, this could conceivably be used to handle that in the future (maybe?). It is not clear if gotalk is striving for any kinds of backwards compatibility between protocol versions, so that’ll be something to watch.
• The Go and JS example client/servers have progressed quite a bit.

python-gotalk updates

At this point in time, we should be current with the gotalk v1 branch wire format (as of the night of Feb 6). I haven’t started on any socket/state tracking stuff, and probably won’t until v1 is mostly solidified.

However, I’ve thought about keeping python-gotalk focused on just the message marshalling/unmarshalling. The socket/state tracking code will differ quite a bit depending on whether you are using Twisted, asyncio, Tornado, etc. It’d also mean that python-gotalk could avoid all external dependencies.

We’ll continue tracking the Gotalk v1 branch and see how it goes!