Thanks explanation Sylvain! If we are talking about generic then it
should be Map<String,Object>. This way you don't restrict the data
type and you let the yaml lib parse the data. With Map<String,Object>
my version of SimpleSeedProvider has these kind of configs without
doing extra text parsing:
version a:
seed_provider:
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
parameters:
seeds: 127.0.0.1
version b:
seed_provider:
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
parameters:
seeds: [127.0.0.1, 127.0.0.2, 127.0.0.3]
Map<String,Object> also allows my custom seed providers to have
complex configuration parameters parsed by the yaml lib too.
On Mon, Oct 31, 2011 at 2:01 AM, Sylvain Lebresne <[email protected]> wrote:
> Because a seed_provider can be custom, you can write your own. The only
> one we ship by default is the SimpleSeedProvided, but you can create your
> own that say, query some service over the network to get the list of seeds.
> So the parameters have to be generic for that to work and having
> the parameters be a Map<String, String> is simple and generic enough.
>
> --
> Sylvain
>
> On Mon, Oct 31, 2011 at 4:21 AM, Kyle Quest <[email protected]> wrote:
>> I noticed a couple of things about the yaml configs in Cassandra:
>>
>> seed_provider:
>> # Addresses of hosts that are deemed contact points.
>> # Cassandra nodes use this list of hosts to find each other and learn
>> # the topology of the ring. You must change this if you are running
>> # multiple nodes!
>> - class_name: org.apache.cassandra.locator.SimpleSeedProvider
>> parameters:
>> # seeds is actually a comma-delimited list of addresses.
>> # Ex: "<ip1>,<ip2>,<ip3>"
>> - seeds: "127.0.0.1" <-- question 1 and 2
>>
>> 1. Why use yaml and then resort to manual parsing of the "seeds"
>> value? Why not let yaml do all of the parsing?
>> 2. If "parameters" is a map (Map<String, String>) then why use the
>> "list" notation (dash in front of "seeds"), which really makes
>> "parameters" a list of maps... The actual Cassandra code then tries to
>> work around this list of maps behavior by explicitly grabbing the
>> first element in the list.
>>
>
