Using CDC is going to be... difficult. First off (to my knowledge) all you get is a CommitLogReader. If you take a look at the Mutation class (everything is serialized and deserialized there), there's no user reference. You only get a keyspace, key, and a PartitionUpdate, which don't include any user information.
Next, you may need to dedupe your messages, since you will get RF messages for every mutation. CDC is per-node, vs triggers which are executed at the coordinator level. This may not apply to you as you only want queries that came through cqlsh, but I don't see a reasonable way to differentiate all the mutations anyway so I think this is a bust. I haven't spent a lot of time in this code, happy to be corrected if I'm wrong. Jon On Fri, Nov 11, 2016 at 10:14 AM siddharth verma < sidd.verma29.l...@gmail.com> wrote: > Hi Sathish, > You could look into, Change Data Capture (CDC) ( > https://issues.apache.org/jira/browse/CASSANDRA-8844 . > It might help you for some of your requirements. > > Regards > Siddharth Verma > > On Fri, Nov 11, 2016 at 11:34 PM, Jonathan Haddad <j...@jonhaddad.com> > wrote: > > cqlsh uses the Python driver, I don't see how there would be any way to > differentiate where the request came from unless you stuck an extra field > in the table that you always write when you're not in cqlsh, or you > modified cqlsh to include that field whenever it did an insert. > > Checking iTrigger source, all you get is a reference to the ColumnFamily > and some metadata. At a glance of trunk, it doesn't look like you get the > user that initiated the query. > > To be honest, I wouldn't do any of this, it feels like it's going to > become an error prone mess. Your best bet is to layer something on top of > the driver yourself. The cleanest way I think think of, long term, is to > submit a JIRA / patch to enable some class loading & listener hooks in > cqlsh itself. Without a patch and a really good use case I don't know who > would want to maintain that though, as it would lock the team into using > Python for cqlsh. > > Jon > > On Fri, Nov 11, 2016 at 9:52 AM sat <sathish.al...@gmail.com> wrote: > > Hi, > > We are planning to use ITrigger to notify changes, when we execute scripts > or run commands in cqlsh prompt. If the operation is performed through our > application CRUD API, we are planning to handle notification in our CRUD > API itself, however if user performs some operation(like write operation in > cqlsh prompt) we want to handle those changes and update modules that are > listening to those changes. > > Could you please let us know whether it is possible to differentiate > updates done through cqlsh prompt and through application. > > We also thought about creating multiple users in cassandra and using > different user for cqlsh and for the application. If we go with this > approach, do we get the user who modified the table in ITrigger > implementation (ie., augment method) > > > Basically we are trying to limit/restrict usage of ITrigger just for cqlsh > prompt as it is little complex and risky (came to know it will impact > cassandra running in that node). > > Thanks and Regards > A.SathishKumar > > > > > -- > Siddharth Verma > (Visit https://github.com/siddv29/cfs for a high speed cassandra full > table scan) >
