diff options
Diffstat (limited to 'src/ceph/examples/librados/hello_world.cc')
| -rw-r--r-- | src/ceph/examples/librados/hello_world.cc | 298 |
1 files changed, 0 insertions, 298 deletions
diff --git a/src/ceph/examples/librados/hello_world.cc b/src/ceph/examples/librados/hello_world.cc deleted file mode 100644 index 48e1fd1..0000000 --- a/src/ceph/examples/librados/hello_world.cc +++ /dev/null @@ -1,298 +0,0 @@ -// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- -// vim: ts=8 sw=2 smarttab -/* - * Ceph - scalable distributed file system - * - * This is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License version 2.1, as published by the Free Software - * Foundation. See file COPYING. - * Copyright 2013 Inktank - */ - -// install the librados-dev package to get this -#include <rados/librados.hpp> -#include <iostream> -#include <string> - -int main(int argc, const char **argv) -{ - int ret = 0; - - // we will use all of these below - const char *pool_name = "hello_world_pool"; - std::string hello("hello world!"); - std::string object_name("hello_object"); - librados::IoCtx io_ctx; - - // first, we create a Rados object and initialize it - librados::Rados rados; - { - ret = rados.init("admin"); // just use the client.admin keyring - if (ret < 0) { // let's handle any error that might have come back - std::cerr << "couldn't initialize rados! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we just set up a rados cluster object" << std::endl; - } - } - - /* - * Now we need to get the rados object its config info. It can - * parse argv for us to find the id, monitors, etc, so let's just - * use that. - */ - { - ret = rados.conf_parse_argv(argc, argv); - if (ret < 0) { - // This really can't happen, but we need to check to be a good citizen. - std::cerr << "failed to parse config options! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we just parsed our config options" << std::endl; - // We also want to apply the config file if the user specified - // one, and conf_parse_argv won't do that for us. - for (int i = 0; i < argc; ++i) { - if ((strcmp(argv[i], "-c") == 0) || (strcmp(argv[i], "--conf") == 0)) { - ret = rados.conf_read_file(argv[i+1]); - if (ret < 0) { - // This could fail if the config file is malformed, but it'd be hard. - std::cerr << "failed to parse config file " << argv[i+1] - << "! error" << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } - break; - } - } - } - } - - /* - * next, we actually connect to the cluster - */ - { - ret = rados.connect(); - if (ret < 0) { - std::cerr << "couldn't connect to cluster! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we just connected to the rados cluster" << std::endl; - } - } - - /* - * let's create our own pool instead of scribbling over real data. - * Note that this command creates pools with default PG counts specified - * by the monitors, which may not be appropriate for real use -- it's fine - * for testing, though. - */ - { - ret = rados.pool_create(pool_name); - if (ret < 0) { - std::cerr << "couldn't create pool! error " << ret << std::endl; - return EXIT_FAILURE; - } else { - std::cout << "we just created a new pool named " << pool_name << std::endl; - } - } - - /* - * create an "IoCtx" which is used to do IO to a pool - */ - { - ret = rados.ioctx_create(pool_name, io_ctx); - if (ret < 0) { - std::cerr << "couldn't set up ioctx! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we just created an ioctx for our pool" << std::endl; - } - } - - /* - * now let's do some IO to the pool! We'll write "hello world!" to a - * new object. - */ - { - /* - * "bufferlist"s are Ceph's native transfer type, and are carefully - * designed to be efficient about copying. You can fill them - * up from a lot of different data types, but strings or c strings - * are often convenient. Just make sure not to deallocate the memory - * until the bufferlist goes out of scope and any requests using it - * have been finished! - */ - librados::bufferlist bl; - bl.append(hello); - - /* - * now that we have the data to write, let's send it to an object. - * We'll use the synchronous interface for simplicity. - */ - ret = io_ctx.write_full(object_name, bl); - if (ret < 0) { - std::cerr << "couldn't write object! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we just wrote new object " << object_name - << ", with contents\n" << hello << std::endl; - } - } - - /* - * now let's read that object back! Just for fun, we'll do it using - * async IO instead of synchronous. (This would be more useful if we - * wanted to send off multiple reads at once; see - * http://docs.ceph.com/docs/master/rados/api/librados/#asychronous-io ) - */ - { - librados::bufferlist read_buf; - int read_len = 4194304; // this is way more than we need - // allocate the completion from librados - librados::AioCompletion *read_completion = librados::Rados::aio_create_completion(); - // send off the request. - ret = io_ctx.aio_read(object_name, read_completion, &read_buf, read_len, 0); - if (ret < 0) { - std::cerr << "couldn't start read object! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } - // wait for the request to complete, and check that it succeeded. - read_completion->wait_for_complete(); - ret = read_completion->get_return_value(); - if (ret < 0) { - std::cerr << "couldn't read object! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we read our object " << object_name - << ", and got back " << ret << " bytes with contents\n"; - std::string read_string; - read_buf.copy(0, ret, read_string); - std::cout << read_string << std::endl; - } - } - - /* - * We can also use xattrs that go alongside the object. - */ - { - librados::bufferlist version_bl; - version_bl.append('1'); - ret = io_ctx.setxattr(object_name, "version", version_bl); - if (ret < 0) { - std::cerr << "failed to set xattr version entry! error " - << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we set the xattr 'version' on our object!" << std::endl; - } - } - - /* - * And if we want to be really cool, we can do multiple things in a single - * atomic operation. For instance, we can update the contents of our object - * and set the version at the same time. - */ - { - librados::bufferlist bl; - bl.append(hello); - bl.append("v2"); - librados::ObjectWriteOperation write_op; - write_op.write_full(bl); - librados::bufferlist version_bl; - version_bl.append('2'); - write_op.setxattr("version", version_bl); - ret = io_ctx.operate(object_name, &write_op); - if (ret < 0) { - std::cerr << "failed to do compound write! error " << ret << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we overwrote our object " << object_name - << " with contents\n" << bl.c_str() << std::endl; - } - } - - /* - * And to be even cooler, we can make sure that the object looks the - * way we expect before doing the write! Notice how this attempt fails - * because the xattr differs. - */ - { - librados::ObjectWriteOperation failed_write_op; - librados::bufferlist bl; - bl.append(hello); - bl.append("v2"); - librados::ObjectWriteOperation write_op; - write_op.write_full(bl); - librados::bufferlist version_bl; - version_bl.append('2'); - librados::bufferlist old_version_bl; - old_version_bl.append('1'); - failed_write_op.cmpxattr("version", LIBRADOS_CMPXATTR_OP_EQ, old_version_bl); - failed_write_op.write_full(bl); - failed_write_op.setxattr("version", version_bl); - ret = io_ctx.operate(object_name, &failed_write_op); - if (ret < 0) { - std::cout << "we just failed a write because the xattr wasn't as specified" - << std::endl; - } else { - std::cerr << "we succeeded on writing despite an xattr comparison mismatch!" - << std::endl; - ret = EXIT_FAILURE; - goto out; - } - - /* - * Now let's do the update with the correct xattr values so it - * actually goes through - */ - bl.clear(); - bl.append(hello); - bl.append("v3"); - old_version_bl.clear(); - old_version_bl.append('2'); - version_bl.clear(); - version_bl.append('3'); - librados::ObjectWriteOperation update_op; - update_op.cmpxattr("version", LIBRADOS_CMPXATTR_OP_EQ, old_version_bl); - update_op.write_full(bl); - update_op.setxattr("version", version_bl); - ret = io_ctx.operate(object_name, &update_op); - if (ret < 0) { - std::cerr << "failed to do a compound write update! error " << ret - << std::endl; - ret = EXIT_FAILURE; - goto out; - } else { - std::cout << "we overwrote our object " << object_name - << " following an xattr test with contents\n" << bl.c_str() - << std::endl; - } - } - - ret = EXIT_SUCCESS; - out: - /* - * And now we're done, so let's remove our pool and then - * shut down the connection gracefully. - */ - int delete_ret = rados.pool_delete(pool_name); - if (delete_ret < 0) { - // be careful not to - std::cerr << "We failed to delete our test pool!" << std::endl; - ret = EXIT_FAILURE; - } - - rados.shutdown(); - - return ret; -} |