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/*
* Copyright (c) 2013, Red Hat
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer. Redistributions in binary
* form must reproduce the above copyright notice, this list of conditions and
* the following disclaimer in the documentation and/or other materials
* provided with the distribution.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Description of an etcd server. For now it just includes the name and
* port, but some day it might include other stuff like SSL certificate
* information.
*/
typedef enum {
ETCD_OK = 0,
ETCD_PROTOCOL_ERROR,
/* TBD: add other error categories here */
ETCD_WTF /* anything we can't easily categorize */
} etcd_result;
typedef struct {
char *host;
unsigned short port;
} etcd_server;
typedef void *etcd_session;
/*
* etcd_open
*
* Establish a session to an etcd cluster, with automatic reconnection and
* so on.
*
* server_list
* Array of etcd_server structures, with the last having host=NULL. The
* caller is responsible for ensuring that this remains valid as long as
* the session exists.
*/
etcd_session etcd_open (etcd_server *server_list);
/*
* etcd_open_str
*
* Same as etcd_open, except that the servers are specified as a list of
* host:port strings, separated by comma/semicolon or whitespace.
*/
etcd_session etcd_open_str (char *server_names);
/*
* etcd_close
*
* Terminate a session, closing connections and freeing memory (or any other
* resources) associated with it.
*/
void etcd_close (etcd_session session);
/*
* etcd_close
*
* Same as etcd_close, but also free the server list as etcd_open_str would
* have allocated it.
*/
void etcd_close_str (etcd_session session);
/*
* etcd_get
*
* Fetch a key from one of the servers in a session. The return value is a
* newly allocated string, which must be freed by the caller.
*
* key
* The etcd key (path) to fetch.
*/
char * etcd_get (etcd_session session, char *key);
/*
* etcd_watch
* Watch the set of keys matching a prefix.
*
* pfx
* The etcd key prefix (like a path) to watch.
*
* keyp
* Space for a pointer to the key that was added/modified/deleted.
*
* valuep
* Space for a pointer to the value if a key was added/modified. A delete
* is signified by this being set to NULL.
*
* index_in
* Pointer to an index to be used for *issuing* the watch request, or
* NULL for a watch without an index.
*
* index_out
* Pointer to space for an index *returned* by etcd, or NULL to mean don't
* bother.
*
* In normal usage, index_in will be NULL and index_out will be set to receive
* the index for the first watch. Subsequently, index_in will be set to
* provide the previous index (plus one) and index_out will be set to receive
* the next. It's entirely legitimate to point both at the same variable.
*/
etcd_result etcd_watch (etcd_session session, char *pfx,
char **keyp, char **valuep,
int *index_in, int *index_out);
/*
* etcd_set
*
* Write a key, with optional TTL and/or previous value (as a precondition).
*
* key
* The etcd key (path) to set.
*
* value
* New value as a null-terminated string. Unlike etcd_get, we can derive
* the length ourselves instead of needing it to be passed in separately.
*
* precond
* Required previous value as a null-terminated string, or NULL to mean
* an unconditional set.
*
* ttl
* Time in seconds after which the value will automatically expire and be
* deleted, or zero to mean no auto-expiration.
*/
etcd_result etcd_set (etcd_session session, char *key, char *value,
char *precond, unsigned int ttl);
/*
* etcd_delete
*
* Delete a key from one of the servers in a session.
*
* key
* The etcd key (path) to delete.
*/
etcd_result etcd_delete (etcd_session session, char *key);
/*
* etcd_leader
*
* Get the identify of the current leader.
*/
char * etcd_leader (etcd_session session);
/*
* etcd_lock
*
* Take or renew a lock - really a lease but the etcd folks call it a lock so
* we'll follow suit.
*
* key
* The path (in the "locks" namespace) for the lock.
*
* ttl
* Time in seconds for the lock.
*
* index_in (optional, indicates renewal)
* Lock index from previous lock call.
*
* index_out (only used for initial lock)
* Place for the new lock index. You must free this.
*/
etcd_result etcd_lock (etcd_session session_as_void, char *key,
unsigned int ttl, char *index_in, char **index_out);
/*
* etcd_unlock
*
* Release a lock (see etcd_lock regarding terminology).
*
* key
* The path (in the "locks" namespace) for the lock.
*
* index
* Lock index from previous lock call.
*/
etcd_result etcd_unlock (etcd_session session_as_void, char *key,
char *index);
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