[sheepdog] [PATCH 0/9] introduce libsheepdog.so

[Liu Yuan]

From: Liu Yuan <liuyuan at cmss.chinamobile.com>

Finally, we kick started, though it is far away from a complete implemention.

This patch set introduces a shared library and for now it only supports simple
vdi operation. The vdi read/write operation would be the most difficult part of
shared library, which require a high-performance request handling. The other
adminsitrative operations, can be implemented on top of a single send-response
helper function, which send the sheep header and get the response.

Currently, it only suppose 6 API:

sd_{connect, disconnect, vdi_open, vdi_read, vdi_write, vdi_close}, but we can
extend it to other commands in the future. The hardest part of the extension is
not the implemention, but the API itself. We need more users inputs and
production experices to shape our future APIs.

The core idea is the same as sbd's framework.

         User request
             |
             | aio control block (struct aiocb)
             V
        +----+----+
        |    |    |
       r1   r2    r3
        |    |    |
        V    V    V
       obj  obj  obj

User request is spit into several sheep requests which are performed on the
individual sheepdog object. All the sheep requests are queued and sent in a
async mode concurently. When all the sheep requests are done, aiocb will try
to user of the completion of the user request.

For future possible other administritive opcodes, we provide a sync function,
which can run the opcode and get the response in a sync mode.

note: "sudo make install" will install the api headers into /usr/include/sheepdog
       and libsheepdog.so into /usr/lib/libsheepdog.so.

A simple example of test.c to make use of libsheepdog.so:

Suppose you have a cluster and a vdi named test.

#include <stdio.h>
#include <stdlib.h>
#include <sheepdog/sheepdog.h>

int main()
{
	struct sd_cluster *c = sd_connect("127.0.0.1:7000");
	struct sd_vdi *vdi;
	char buf[512] = {};

	if (!c) {
		fprintf(stderr, "failed to connect %m\n");
		return -1;
	}

	vdi = sd_vdi_open(c, "test");
	if (!vdi) {
		fprintf(stderr, "failed to open %m\n");
		return -1;
	}

	sd_vdi_write(vdi, "hello world!\n", 512, 0);
	sd_vdi_read(vdi, buf, 512, 0);
	sd_vdi_close(vdi);
	printf("%s", buf);
	return 0;
}

compile:
 $ gcc test.c -lsheepdog -lpthread

./a.out will show you "hello world!" if all goes well.

Liu Yuan (8):
  add sd_assert()
  move functions used by libsheepdog.a out of util.c
  sheep: dissociate utils.c from logger.c
  move sheep specific headers out of sheepdog_proto.h
  unralate list.h, util.h to compiler.h
  shared lib: add the low level request handling framework
  shared lib: implement vdi_{open, read, write, close}
  shared lib: kick it run

 configure.ac              |  14 +-
 dog/common.c              |  25 ++
 dog/dog.h                 |   6 +
 dog/treeview.c            |   1 +
 include/Makefile.am       |   3 +-
 include/compiler.h        |   9 -
 include/fec.h             |   1 +
 include/list.h            |   2 -
 include/logger.h          |  11 +-
 include/sheep.h           |  14 +
 include/sheepdog_proto.h  |  16 +-
 include/util.h            |  69 +++--
 include/work.h            |   1 +
 lib/Makefile.am           |  17 +-
 lib/common.c              | 279 ++++++++++++++++++++
 lib/event.c               |   1 +
 lib/fec.c                 |  15 +-
 lib/logger.c              |   6 +-
 lib/sd_inode.c            |   1 +
 lib/shared/sheep.c        | 642 ++++++++++++++++++++++++++++++++++++++++++++++
 lib/shared/sheepdog.h     |  74 ++++++
 lib/shared/vdi.c          | 185 +++++++++++++
 lib/util.c                | 285 +-------------------
 lib/work.c                |   2 +-
 sheep/cluster.h           |   1 +
 sheep/cluster/corosync.c  |   2 +-
 sheep/cluster/shepherd.c  |   4 +-
 sheep/cluster/zookeeper.c |   2 +-
 sheep/group.c             |   6 +-
 sheep/md.c                |   4 +-
 sheep/migrate.c           |   2 +-
 sheep/object_cache.c      |   6 +-
 sheep/ops.c               |   6 +-
 sheep/plain_store.c       |   2 +-
 sheep/request.c           |  10 +-
 sheep/sheep.c             |   2 +-
 sheep/sheep_priv.h        |   1 +
 sheep/trace/trace.c       |   4 +-
 sheep/vdi.c               |  16 +-
 sheepfs/core.c            |   1 +
 shepherd/shepherd.c       |   1 +
 41 files changed, 1343 insertions(+), 406 deletions(-)
 create mode 100644 lib/common.c
 create mode 100644 lib/shared/sheep.c
 create mode 100644 lib/shared/sheepdog.h
 create mode 100644 lib/shared/vdi.c

-- 
1.9.1