+++ /dev/null
-// -*- 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;
-}
Code Review / stor4nfv.git / blobdiff