Seems plausible to me.
Daniel
On 8/31/22 16:14, Casey Bodley wrote:
all rgws in a zone need to serve the same data set, so we've agreed
that their store configuration belongs in the RGWZoneParams object
that they share. RGWZoneParams can already be parsed/serialized as
json, so i'm proposing that we add the store configuration as a nested
opaque json object
the simplest configuration could look something like this:
"stores": {
"type": "rados"
}
a rados backend with a caching filter in front could look like:
"stores": {
"type": "cache",
"size": 512,
"backend": {
"type": "rados"
}
}
a more complicated example, where a cloud_filter redirects requests on
buckets starting with 'cloud' to a remote s3 service, and satisfies
everything else from a cached database backend:
"stores": {
"type": "cloud_filter",
"remote bucket prefix": "cloud",
"remote backend": {
"type": "s3",
"endpoint": "s3.example.com",
"credentials": "password"
},
"local backend": {
"type": "cache",
"backend": {
"type": "dbstore"
}
}
}
each store definition requires a "type" so rgw knows which SAL driver
to load, but all other fields (including nested backend stores) are
only interpreted by that driver
so given this json object 'stores', we can write a Store factory that
recursively builds this tree of stores and returns the root. for the
cloud_filter driver example (with error handling omitted):
rgw_sal.cc:
unique_ptr<rgw::sal::Store> rgw::sal::load_store(JSONObj* json)
{
std::string store_type;
JSONDecoder::decode_json("store", store_type, json);
// load the sal driver and call its sal_create()
auto filename = fmt::format("/path/to/libsal_{}.so", store_type);
void* handle = ::dlopen(filename.c_str(), ...);
sal_create_fn sal_create = ::dlsym(handle, "sal_create");
return sal_create(json);
}
libsal_cloud_filter.so:
rgw::sal::Store* sal_create(JSONObj* json)
{
// load the backends
JSONObj* remote_json = json->find("remote backend");
unique_ptr<rgw::sal::Store> remote_backend =
rgw::sal::load_store(remote_json);
JSONObj* local_json = json->find("local backend");
unique_ptr<rgw::sal::Store> local_backend = rgw::sal::load_store(local_json);
std::string prefix;
JSONDecoder::decode_json("remote bucket prefix", store_type, json);
return new CloudFilterStore(prefix, std::move(remote_backend),
std::move(local_backend));
}
_______________________________________________
Dev mailing list -- dev@xxxxxxx
To unsubscribe send an email to dev-leave@xxxxxxx
