How to use librados Interface in ceph

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Rados_getxattr gets object properties

Rados_getxattrs gets the list of object attributes

Rados_getxattrs_next reads values from the acquired list of object properties

Rados_getxattrs_end releases the pointer obtained by rados_getxattrs

Rados_setxattr sets the custom properties of an object

Rados_rmxattr deletes custom properties of an object

Rados_stat returns the time and size of the object

Rados_tmap_update

Rados_tmap_put

Rados_tmap_get

Rados_tmap_to_omap

Use the example

# include

# include

# include

Int main (int argc, const char * * argv)

{

Int ret = 0

/ *

* Errors are not checked to avoid pollution.

* After each Ceph operation:

* if (ret

< 0) error_condition * else success */ // Get cluster handle and connect to cluster std::string cluster_name("ceph"); std::string user_name("client.admin"); librados::Rados cluster ; cluster.init2(user_name.c_str(), cluster_name.c_str(), 0); cluster.conf_read_file("/etc/ceph/ceph.conf"); cluster.connect(); // IO context librados::IoCtx io_ctx ; std::string pool_name("data"); cluster.ioctx_create(pool_name.c_str(), io_ctx); // Write an object synchronously librados::bufferlist bl; std::string objectId("hw"); std::string objectContent("Hello World!"); bl.append(objectContent); io_ctx.write(objectId, bl, objectContent.size(), 0); // Add an xattr to the object. librados::bufferlist lang_bl; lang_bl.append("en_US"); io_ctx.setxattr(objectId, "lang", lang_bl); // Read the object back asynchronously librados::bufferlist read_buf; int read_len = 4194304; //Create I/O Completion. librados::AioCompletion *read_completion = librados::Rados::aio_create_completion(); //Send read request. io_ctx.aio_read(objectId, read_completion, &read_buf, read_len, 0 ); // Wait for the request to complete, and print content read_completion->

Wait_for_complete ()

Read_completion- > get_return_value ()

Std::cout