Add python bindings for rados

Signed-off-by: Colin McCabe <colin.mccabe@dreamhost.com>

1 files changed, 233 insertions, 0 deletions

diff --git a/src/pybind/rados.py b/src/pybind/rados.py
new file mode 100755
index 00000000000..e4510898bf7
--- /dev/null
+++ b/src/pybind/rados.py
@@ -0,0 +1,233 @@
+"""librados Python ctypes wrapper
+Copyright 2011, Hannu Valtonen <hannu.valtonen@ormod.com>
+"""
+from ctypes import CDLL, c_char_p, c_size_t, c_void_p,\
+    create_string_buffer, byref, Structure, c_uint64, pointer
+import time
+
+class RadosError(Exception):
+    pass
+
+class ObjectNotFound(Exception):
+    pass
+
+class WriteError(Exception):
+    pass
+
+class IncompleteWriteError(Exception):
+    pass
+
+class rados_pool_stat_t(Structure):
+    _fields_ = [("num_bytes", c_uint64),
+                ("num_kb", c_uint64),
+                ("num_objects", c_uint64),
+                ("num_object_clones", c_uint64),
+                ("num_object_copies", c_uint64),
+                ("num_objects_missing_on_primary", c_uint64),
+                ("num_objects_unfound", c_uint64),
+                ("num_objects_degraded", c_uint64),
+                ("num_rd", c_uint64),
+                ("num_rd_kb", c_uint64),
+                ("num_wr", c_uint64),
+                ("num_wr_kb", c_uint64)]
+
+def object_deleted(method):
+    def wrapper(self, *args, **kwargs):
+        try:
+            if self.deleted == False:
+                return method(self, *args, **kwargs)
+            else:
+                raise ObjectNotFound("Object has been deleted")
+        except:
+            raise
+    wrapper.__doc__ = method.__doc__
+    wrapper.__name__ = method.__name__
+    return wrapper
+
+class Rados(object):
+    """librados python wrapper"""
+    def __init__(self):
+        self.librados = CDLL('librados.so')
+        ret = self.librados.rados_initialize(None)
+        if ret != 0:
+            raise RadosError("rados_initialize failed with error code: %d" \
+                    % ret)
+        self.initialized = True
+
+    def __del__(self):
+        if (self.__dict__.has_key("initialized") and self.initialized == True):
+            self.librados.rados_deinitialize()
+
+    def create_pool(self, pool_name):
+        ret = self.librados.rados_create_pool(c_char_p(pool_name))
+        if ret < 0:
+            raise RadosError("pool %s couldn't be created" % pool_name)
+
+    def delete_pool(self, pool):
+        ret = self.librados.rados_delete_pool(pool)
+        if ret < 0:
+            raise RadosError("pool couldn't be deleted")
+
+    def get_pool(self, pool_name):
+        try:
+            pool = self.open_pool(pool_name)
+        except RadosError:
+            self.create_pool(pool_name)
+            pool = self.open_pool(pool_name)
+        return pool
+
+    def open_pool(self, pool_name):
+        pool = c_void_p()
+        ret = self.librados.rados_open_pool(c_char_p(pool_name), byref(pool))
+        if ret < 0:
+            raise RadosError("pool %s couldn't be opened" % pool_name)
+        return Pool(self.librados, pool)
+
+    def close_pool(self, pool):
+        ret = self.librados.rados_close_pool(pool)
+        if ret < 0:
+            raise RadosError("pool couldn't be closed")
+
+class Pool(object):
+    """Pool object"""
+    def __init__(self, librados, pool):
+        self.librados = librados
+        self.pool = pool
+        self.deleted = False
+
+    @object_deleted
+    def get_object(self, key):
+        return Object(self, key)
+
+    @object_deleted
+    def write(self, key, string_to_write, offset = 0):
+        length = len(string_to_write)
+        ret = self.librados.rados_write(self.pool, c_char_p(key),
+                    c_size_t(offset), c_char_p(string_to_write),
+                    c_size_t(length))
+        if ret == length:
+            return ret
+        elif ret < 0:
+            raise WriteError("Write failed completely")
+        elif ret < length:
+            raise IncompleteWriteError("Wrote only %ld/%ld bytes" % (ret, length))
+        else:
+            raise RadosError("something weird happened while writing")
+
+    @object_deleted
+    def read(self, key, offset = 0, length = 8192):
+        ret_buf = create_string_buffer(length)
+        ret = self.librados.rados_read(self.pool, c_char_p(key), c_size_t(offset),
+                                        ret_buf, c_size_t(length))
+        if ret < 0:
+            raise RadosError("Read failure, object doesn't exist?")
+        return ret_buf.value
+
+    @object_deleted
+    def get_stats(self):
+        stats = rados_pool_stat_t()
+        ret = self.librados.rados_stat_pool(self.pool, byref(stats))
+        if ret < 0:
+            raise RadosError("Couldn't get stats from pool")
+        return {'num_bytes': stats.num_bytes,
+                'num_kb': stats.num_kb,
+                'num_objects': stats.num_objects,
+                'num_object_clones': stats.num_object_clones,
+                'num_object_copies': stats.num_object_copies,
+                "num_objects_missing_on_primary": stats.num_objects_missing_on_primary,
+                "num_objects_unfound": stats.num_objects_unfound,
+                "num_objects_degraded": stats.num_objects_degraded,
+                "num_rd": stats.num_rd,
+                "num_rd_kb": stats.num_rd_kb,
+                "num_wr": stats.num_wr,
+                "num_wr_kb": stats.num_wr_kb }
+
+    @object_deleted
+    def remove_object(self, key):
+        ret = self.librados.rados_remove(self.pool, c_char_p(key))
+        if ret < 0:
+            raise RadosError("Delete failure")
+        return True
+
+    @object_deleted
+    def stat(self, key):
+        """Stat object, returns, size/timestamp"""
+        psize = c_uint64()
+        pmtime = c_uint64()
+
+        ret = self.librados.rados_stat(self.pool, c_char_p(key), pointer(psize),
+                                        pointer(pmtime))
+        if ret < 0:
+            raise RadosError("Failed to stat %r" % key)
+        return psize.value, time.localtime(pmtime.value)
+
+    @object_deleted
+    def get_xattr(self, key, xattr_name):
+        ret_length = 4096
+        ret_buf = create_string_buffer(ret_length)
+        ret = self.librados.rados_getxattr(self.pool, c_char_p(key),
+                    c_char_p(xattr_name), ret_buf, c_size_t(ret_length))
+        if ret < 0:
+            raise RadosError("Failed to get xattr %r" % xattr_name)
+        return ret_buf.value
+
+    @object_deleted
+    def set_xattr(self, key, xattr_name, xattr_value):
+        ret = self.librados.rados_setxattr(self.pool, c_char_p(key),
+                    c_char_p(xattr_name), c_char_p(xattr_value),
+                    c_size_t(len(xattr_value)))
+        if ret < 0:
+            raise RadosError("Failed to set xattr %r" % xattr_name)
+        return True
+
+    @object_deleted
+    def rm_xattr(self, key, xattr_name):
+        ret = self.librados.rados_rmxattr(self.pool, c_char_p(key), c_char_p(xattr_name))
+        if ret < 0:
+            raise RadosError("Failed to delete key %r xattr %r" % (key, xattr_name))
+        return True
+
+class Object(object):
+    """Rados object wrapper, makes the object look like a file"""
+    def __init__(self, pool, key):
+        self.key = key
+        self.pool = pool
+        self.offset = 0
+        self.deleted = False
+
+    @object_deleted
+    def read(self, length = 1024*1024):
+        ret = self.pool.read(self.key, self.offset, length)
+        self.offset += len(ret)
+        return ret
+
+    @object_deleted
+    def write(self, string_to_write):
+        ret = self.pool.write(self.key, string_to_write, self.offset)
+        self.offset += ret
+        return ret
+
+    @object_deleted
+    def remove(self):
+        self.pool.remove_object(self.key)
+        self.deleted = True
+
+    @object_deleted
+    def stat(self):
+        return self.pool.stat(self.key)
+
+    @object_deleted
+    def seek(self, position):
+        self.offset = position
+
+    @object_deleted
+    def get_xattr(self, xattr_name):
+        return self.pool.get_xattr(self.key, xattr_name)
+
+    @object_deleted
+    def set_xattr(self, xattr_name, xattr_value):
+        return self.pool.set_xattr(self.key, xattr_name, xattr_value)
+
+    @object_deleted
+    def rm_xattr(self, xattr_name):
+        return self.pool.rm_xattr(self.key, xattr_name)