* Stream replay support

* RFC8040 Restconf replay support: start-time and stop-time query parameter support
    * This only applies to "native" restconf stream support, Nchan mode has different replay functionality
  * RFC5277 Netconf replay support using <startTime> and
  * Replay support is only in-memory and not persistent. External time-series DB could be added.

CHANGELOG.md

@@ -33,6 +33,11 @@
   * Optional pub/sub support enabled by ./configure --enable-publish
     * Set publish URL base with: CLICON_STREAM_PUB (default http://localhost/pub)
     * Example: new stream "foo" will get pub URL: https://localhost/pub/foo
+* Stream replay support
+  * RFC8040 Restconf replay support: start-time and stop-time query parameter support
+    * This only applies to "native" restconf stream support, Nchan mode has different replay functionality
+  * RFC5277 Netconf replay support using <startTime> and
+  * Replay support is only in-memory and not persistent. External time-series DB could be added.
 
 ### API changes on existing features (you may need to change your code)
 * clixon-config YAML file has new revision: 2018-10-21.
@@ -94,7 +99,9 @@
 * Set dir /www-data with www-data as owner, see https://github.com/clicon/clixon/issues/37
 	
 ### Known issues
-* Bug: Top-level Yang symbol cannot be called "config" in any imported yang file.
+* netconf rpc input is not sanity checked for wrong symbols (just ignored).
+* Yang sub-command order and cardinality not checked.
+* Top-level Yang symbol cannot be called "config" in any imported yang file.
   * datastore uses "config" as reserved keyword for storing any XML whoich collides with code for detecting Yang sanity.
 * Namespace name relabeling is not supported.
   * Eg: if "des" is defined as prefix for an imported module, then a relabeling using xmlfns is not supported, such as:

apps/backend/backend_client.c

@@ -815,12 +815,13 @@ from_client_delete_config(clicon_handle h,
  * @param[out]  cbret Return xml value cligen buffer
  * @retval      0    OK
  * @retval      -1   Error. Send error message back to client.
+ * @see RFC5277 2.1
  * @example:
  *    <create-subscription> 
  *       <stream>RESULT</stream> # If not present, events in the default NETCONF stream will be sent.
  *       <filter type="xpath" select="XPATH-EXPR"/>
- *       <startTime/> # only for replay (NYI)
+ *       <startTime></startTime>
- *       <stopTime/>  # only for replay (NYI)
+ *       <stopTime></stopTime>
  *    </create-subscription> 
  */
 static int
@@ -834,10 +835,28 @@ from_client_create_subscription(clicon_handle        h,
     cxobj  *x; /* Generic xml tree */
     cxobj  *xfilter; /* Filter xml tree */
     char   *ftype;
+    char   *starttime = NULL;
+    char   *stoptime = NULL;
     char   *selector = NULL;
+    struct timeval start;
+    struct timeval stop;
 
     if ((x = xpath_first(xe, "//stream")) != NULL)
 	stream = xml_find_value(x, "body");
+    if ((x = xpath_first(xe, "//stopTime")) != NULL){
+	stoptime = xml_find_value(x, "body");
+	if (str2time(stoptime, &stop) < 0){
+	    clicon_err(OE_PROTO, errno, "str2time");
+	    goto done;	
+	}
+    }
+    if ((x = xpath_first(xe, "//startTime")) != NULL){
+	starttime = xml_find_value(x, "body");
+	if (str2time(starttime, &start) < 0){
+	    clicon_err(OE_PROTO, errno, "str2time");
+	    goto done;	
+	}	
+    }
     if ((xfilter = xpath_first(xe, "//filter")) != NULL){
 	if ((ftype = xml_find_value(xfilter, "type")) != NULL){
 	    /* Only accept xpath as filter type */
@@ -855,7 +874,12 @@ from_client_create_subscription(clicon_handle        h,
 	    goto done;
 	goto ok;
     }
-    if (stream_cb_add(h, stream, selector, ce_event_cb, (void*)ce) < 0)
+    if (stream_cb_add(h, stream, selector, stoptime?&stop:NULL,
+		      ce_event_cb, (void*)ce) < 0)
+	goto done;
+    /* Replay of this stream to specific subscription according to start and stop*/
+    if (starttime) /* XXX No this must be done _after_ this RPC completes */
+	if (stream_replay(h, stream, &start, stoptime?&stop:NULL) < 0)
 	    goto done;
     cprintf(cbret, "<rpc-reply><ok/></rpc-reply>");
  ok:

apps/backend/backend_main.c

@@ -89,6 +89,8 @@ backend_terminate(clicon_handle h)
     clicon_debug(1, "%s", __FUNCTION__);
     if ((yspec = clicon_dbspec_yang(h)) != NULL)
 	yspec_free(yspec);
+    if ((yspec = clicon_config_yang(h)) != NULL)
+	yspec_free(yspec);
     if ((x = clicon_conf_xml(h)) != NULL)
 	xml_free(x);
     stream_publish_exit();
@@ -590,6 +592,7 @@ main(int    argc,
 	    usage(h, argv[0]);
 	return -1;
     }
+    clicon_config_yang_set(h, yspecfg);
     /* External NACM file? */
     nacm_mode = clicon_option_str(h, "CLICON_NACM_MODE");
     if (nacm_mode && strcmp(nacm_mode, "external") == 0)

apps/cli/cli_main.c

@@ -85,6 +85,8 @@ cli_terminate(clicon_handle h)
     clicon_rpc_close_session(h);
     if ((yspec = clicon_dbspec_yang(h)) != NULL)
 	yspec_free(yspec);
+    if ((yspec = clicon_config_yang(h)) != NULL)
+	yspec_free(yspec);
     if ((x = clicon_conf_xml(h)) != NULL)
 	xml_free(x);
     cli_plugin_finish(h);    
@@ -338,7 +340,7 @@ main(int argc, char **argv)
 	    usage(h, argv[0]);
 	return -1;
     }
-
+    clicon_config_yang_set(h, yspecfg);
     /* Now rest of options */   
     opterr = 0;
     optind = 1;

apps/netconf/netconf_main.c

@@ -280,6 +280,8 @@ netconf_terminate(clicon_handle h)
     clicon_rpc_close_session(h);
     if ((yspec = clicon_dbspec_yang(h)) != NULL)
 	yspec_free(yspec);
+    if ((yspec = clicon_config_yang(h)) != NULL)
+	yspec_free(yspec);
     if ((x = clicon_conf_xml(h)) != NULL)
 	xml_free(x);
     event_exit();
@@ -390,7 +392,7 @@ main(int    argc,
     /* Find and read configfile */
     if (clicon_options_main(h, yspecfg) < 0)
 	return -1;
-
+    clicon_config_yang_set(h, yspecfg);
     /* Now rest of options */
     optind = 1;
     opterr = 0;

apps/restconf/restconf_main.c

@@ -454,6 +454,8 @@ restconf_terminate(clicon_handle h)
     clicon_rpc_close_session(h);
     if ((yspec = clicon_dbspec_yang(h)) != NULL)
 	yspec_free(yspec);
+    if ((yspec = clicon_config_yang(h)) != NULL)
+	yspec_free(yspec);
     if ((x = clicon_conf_xml(h)) != NULL)
 	xml_free(x);
     clicon_handle_exit(h);
@@ -583,6 +585,7 @@ main(int    argc,
     /* Find and read configfile */
     if (clicon_options_main(h, yspecfg) < 0)
 	goto done;
+    clicon_config_yang_set(h, yspecfg);
     stream_path = clicon_option_str(h, "CLICON_STREAM_PATH");
     /* Now rest of options, some overwrite option file */
     optind = 1;

example/example_backend.c

@@ -301,7 +301,7 @@ clixon_plugin_init(clicon_handle h)
      * 2) setup timer for notifications, so something happens on stream
      * 3) setup stream callbacks for notification to push channel
      */
-    if (stream_register(h, "EXAMPLE", "Example event stream") < 0)
+    if (stream_register(h, "EXAMPLE", "Example event stream", 1) < 0)
 	goto done;
     /* assumes: CLIXON_PUBLISH_STREAMS, eg configure --enable-publish
      */

lib/clixon/clixon_options.h

@@ -165,6 +165,11 @@ int clicon_quiet_mode_set(clicon_handle h, int val);
 yang_spec * clicon_dbspec_yang(clicon_handle h);
 int clicon_dbspec_yang_set(clicon_handle h, struct yang_spec *ys);
 
+#if 1 /* Temporary function until "Top-level Yang symbol cannot be called "config"" is fixed */
+yang_spec * clicon_config_yang(clicon_handle h);
+int clicon_config_yang_set(clicon_handle h, struct yang_spec *ys);
+#endif
+
 cxobj *clicon_conf_xml(clicon_handle h);
 int clicon_conf_xml_set(clicon_handle h, cxobj *x);
 

lib/clixon/clixon_queue.h

@@ -37,16 +37,29 @@
 #ifndef _CLIXON_QUEUE_H_
 #define _CLIXON_QUEUE_H_
 
-/*
+/*! Circular queue structure for use as first entry in a parent structure.
- * Circular queue structure for use as first entry in a parent structure.
+ * Add qelem_t as first element in struct
+ * @code
+ * struct a{
+ *   qelem_t a_q; # this must be there
+ *   int     a_b; # other elements
+ *   ...
+ * };
+ * @endcode
  */
 typedef struct _qelem_t {
 	struct _qelem_t  *q_next;
 	struct _qelem_t  *q_prev;
 } qelem_t;
 
-  /*
+/*! Append element 'elem' to queue.
-  * Append element 'elem' to queue.
+ * @param[in]     elem   Element to be added
+ * @param[in,out] pred   Add element after this
+ * @code
+ *   struct a *list; # existing list
+ *   struct a *new = malloc(...);
+ *  ADDQ(new, list);
+ * @endcode
  */
 #define ADDQ(elem, pred) { \
 	register qelem_t *Xe = (qelem_t *) (elem);	\
@@ -62,8 +75,14 @@ typedef struct _qelem_t {
 	}						\
     }
 
-/*
+/*! Insert element 'elem' in queue after 'pred'
- * Insert element 'elem' in queue after 'pred'
+ * @param[in]     elem   Element to be added
+ * @param[in,out] pred   Add element after this
+ * @code
+ *   struct a *list; # existing list
+ *   struct a *new = malloc(...);
+ *   INSQ(new, list);
+ * @endcode
  */
 #define INSQ(elem, pred) { \
 		register qelem_t *Xe = (qelem_t *) (elem); \
@@ -79,9 +98,16 @@ typedef struct _qelem_t {
 		pred = elem;				   \
     }
 
-/*
+/*! Remove element 'elem' from queue. 'head' is the pointer to the queue and 
- * Remove element 'elem' from queue. 'head' is the pointer to the queue and 
  * is of 'type'.
+ * @param[in]  elem
+ * @param[in]  head
+ * @param[in]  type  XXX needed?
+ * @code
+ *   struct a *list; # existing list
+ *   struct a *el; # remove this
+ *  DELQ(el, list, struct a*);
+ * @endcode
  */
 #define	DELQ(elem, head, type)	{ \
     		register qelem_t *Xe = (qelem_t *) elem; \
@@ -92,10 +118,13 @@ typedef struct _qelem_t {
 			head = (type)Xe->q_next; \
 	}
 	
-/*
+/*! Get next entry in list
- * Get next entry in list
+ * @param[in]  type  Type of element
+ * @param[in]  el    Return next element after elem.
+ * @code
+ *  struct a *list; # existing element (or list)
+ *  NEXTQ(struct a*, el);
  */
 #define NEXTQ(type, elem)	((type)((elem)?((qelem_t *)(elem))->q_next:NULL))
 
-
 #endif	/* _CLIXON_QUEUE_H_ */

lib/clixon/clixon_stream.h

@@ -51,10 +51,18 @@ struct stream_subscription{
     struct stream_subscription *ss_next;
     char                       *ss_stream; /* Name of associated stream */
     char                       *ss_xpath;  /* Filter selector as xpath */
+    struct timeval              ss_stoptime; /* Replay stoptime */
     stream_fn_t                 ss_fn;     /* Callback when event occurs */
     void                       *ss_arg;    /* Callback argument */
 };
 
+/* Replay time-series */
+struct stream_replay{
+    qelem_t        r_q;   /* queue header */
+    struct timeval r_tv;  /* time index */
+    cxobj         *r_xml; /* event in xml form */
+};
+
 /* See RFC8040 9.3, stream list, no replay support for now
  */
 struct event_stream{
@@ -62,6 +70,8 @@ struct event_stream{
     char                *es_name; /* name of notification event stream */
     char                *es_description;
     struct stream_subscription *es_subscription;
+    int                  es_replay_enabled; /* set if replay is enables */
+    struct stream_replay *es_replay;
 };
 typedef struct event_stream event_stream_t;
 
@@ -69,25 +79,26 @@ typedef struct event_stream event_stream_t;
  * Prototypes
  */
 event_stream_t *stream_find(clicon_handle h, const char *name);
-int stream_register(clicon_handle h, const char *name, const char *description);
+int stream_register(clicon_handle h, const char *name, const char *description, int replay_enabled);
 int stream_delete_all(event_stream_t *es);
 int stream_get_xml(clicon_handle h, int access, cbuf *cb);
-int stream_cb_add(clicon_handle h, char *stream, char *xpath, stream_fn_t fn, void *arg);
+struct stream_subscription *stream_cb_add(clicon_handle h, char *stream,
+		  char *xpath, struct timeval *stop, stream_fn_t fn, void *arg);
 int stream_cb_delete(clicon_handle h, char *stream, stream_fn_t fn, void *arg);
-int stream_notify_xml(clicon_handle h, char *stream, cxobj *xevent);
+int stream_notify_xml(clicon_handle h, event_stream_t *es, cxobj *xevent);
 #if defined(__GNUC__) && __GNUC__ >= 3
 int stream_notify(clicon_handle h, char *stream, const char *event, ...)  __attribute__ ((format (printf, 3, 4)));
 #else
 int stream_notify(clicon_handle h, char *stream, const char *event, ...);
 #endif
 
-/* Experimental publish streams using SSE */
+
+int stream_replay(clicon_handle h, char *stream, struct timeval *start, struct timeval *stop);
+int stream_replay_add(event_stream_t *es, struct timeval *tv, cxobj *xv);
+
+/* Experimental publish streams using SSE. CLIXON_PUBLISH_STREAMS should be set */
 int stream_publish(clicon_handle h, char *stream);
 int stream_publish_init();
 int stream_publish_exit();
 
-/* Backward compatible macro for <1.8 */
-#define backend_notify_xml(h, stream, level, x) stream_notify_xml(h, stream, x)
-#define backend_notify(h, stream, level, event) stream_notify(h, stream, event)
-
 #endif /* _CLIXON_STREAM_H_ */

lib/src/clixon_options.c

@@ -588,6 +588,40 @@ clicon_dbspec_yang_set(clicon_handle     h,
     return 0;
 }
 
+#if 1 /* Temporary function until "Top-level Yang symbol cannot be called "config"" is fixed */
+/*! Get YANG specification for clixon config
+ * Must use hash functions directly since they are not strings.
+ */
+yang_spec *
+clicon_config_yang(clicon_handle h)
+{
+    clicon_hash_t  *cdat = clicon_data(h);
+    size_t          len;
+    void           *p;
+
+    if ((p = hash_value(cdat, "control_yang", &len)) != NULL)
+	return *(yang_spec **)p;
+    return NULL;
+}
+
+/*! Set yang specification for control
+ * ys must be a malloced pointer
+ */
+int
+clicon_config_yang_set(clicon_handle     h, 
+		       struct yang_spec *ys)
+{
+    clicon_hash_t  *cdat = clicon_data(h);
+
+    /* It is the pointer to ys that should be copied by hash,
+       so we send a ptr to the ptr to indicate what to copy.
+     */
+    if (hash_add(cdat, "control_yang", &ys, sizeof(ys)) == NULL)
+	return -1;
+    return 0;
+}
+#endif
+
 /*! Get YANG specification for Clixon system options and features
  * Must use hash functions directly since they are not strings.
  * Example: features are typically accessed directly in the config tree.

lib/src/clixon_stream.c

@@ -32,7 +32,11 @@
   ***** END LICENSE BLOCK *****
 
  * Event notification streams according to RFC5277
- * See (old) subscription code in clixon_backend_handle.c and backend_client.c
+ * The stream implementation has three parts:
+ * 1) Base stream handling: stream_find/register/delete_all/get_xml
+ * 2) Callback and notification handling (stream_cb_add/delete/timeout, stream_notify, etc
+ * 3) Stream replay: stream_replay/_add
+ * 4) nginx/nchan publish code (use --enable-publish config option)
  */
 
 #ifdef HAVE_CONFIG_H
@@ -88,7 +92,8 @@ stream_find(clicon_handle h,
 int
 stream_register(clicon_handle h,
 		const char   *name, 
-		const char   *description) 
+		const char   *description,
+    		const int     replay_enabled) 
 {
     int             retval = -1;
     event_stream_t *es;
@@ -108,6 +113,7 @@ stream_register(clicon_handle h,
 	clicon_err(OE_XML, errno, "strdup");
 	goto done;
     }
+    es->es_replay_enabled = replay_enabled;
     clicon_stream_append(h, es);
  ok:
     retval = 0;
@@ -122,6 +128,7 @@ int
 stream_delete_all(event_stream_t *es)
 {
     event_stream_t       *e_next;
+    struct stream_replay *r;
     
     while (es){
 	e_next = es->es_next;
@@ -129,13 +136,19 @@ stream_delete_all(event_stream_t *es)
 	    free(es->es_name);
 	if (es->es_description)
 	    free(es->es_description);
+	while ((r = es->es_replay) != NULL){
+	    if (r->r_xml)
+		xml_free(r->r_xml);
+	    DELQ(r, es->es_replay, struct stream_replay *);
+	    free(r);
+	}
 	free(es);
 	es = e_next;
     }
     return 0;
 }
 
-/*! Return stream definition
+/*! Return stream definition state in XML supporting RFC 8040 and RFC5277
  * @param[in]  h      Clicon handle
  * @param[in]  access If set, include access/location
  * @param[out] cb     Output buffer containing XML on exit
@@ -189,21 +202,22 @@ stream_del()
  * @param[in]  h      Clicon handle
  * @param[in]  stream Name of stream
  * @param[in]  xpath  Filter selector - xpath
+ * @param[in]  stoptime If set, 
  * @param[in]  fn     Callback when event occurs
  * @param[in]  arg    Argument to use with callback. Also handle when deleting
  * @retval     0      OK
  * @retval     -1     Error, ie no such stream 
  */
-int
+struct stream_subscription *
 stream_cb_add(clicon_handle     h,
 	      char             *stream,
 	      char             *xpath,
+	      struct timeval   *stoptime,
 	      stream_fn_t       fn,
 	      void             *arg)
 {
-    int                         retval = -1;
     event_stream_t             *es;
-    struct stream_subscription *ss;
+    struct stream_subscription *ss = NULL;
 
     clicon_debug(1, "%s", __FUNCTION__);
     if ((es = stream_find(h, stream)) == NULL){
@@ -219,6 +233,8 @@ stream_cb_add(clicon_handle     h,
 	clicon_err(OE_CFG, errno, "strdup");
 	goto done;
     }
+    if (stoptime)
+	ss->ss_stoptime = *stoptime;
     if (xpath && (ss->ss_xpath = strdup(xpath)) == NULL){
 	clicon_err(OE_CFG, errno, "strdup");
 	goto done;
@@ -227,9 +243,11 @@ stream_cb_add(clicon_handle     h,
     ss->ss_arg    = arg;
     ss->ss_next   = es->es_subscription;
     es->es_subscription = ss;
-    retval = 0;
+    return ss;
   done:
-    return retval;
+    if (ss)
+	free(ss);
+    return NULL;
 }
 
 /*! Delete event notification callback to a stream given a callback and arg
@@ -240,25 +258,18 @@ stream_cb_add(clicon_handle     h,
  * @retval     0      OK
  * @retval     -1     Error
  */
-int
+static int
-stream_cb_delete(clicon_handle     h,
+stream_cb_rm(event_stream_t              *es,
-		 char             *stream,
+	     struct stream_subscription  *ssrm)
-		 stream_fn_t       fn,
-		 void             *arg)
 {
-    int                          retval = -1;
-    event_stream_t              *es;
     struct stream_subscription **ss_prev;
     struct stream_subscription  *ss;
     struct stream_subscription  *ss_next;
     
-    for (es=clicon_stream(h); es; es=es->es_next){
-	if (stream && strcmp(stream, es->es_name)!=0)
-	    continue;
     ss_prev = &es->es_subscription;
     for (ss = *ss_prev; ss; ss = ss_next){
 	ss_next = ss->ss_next;
-	    if (fn == ss->ss_fn && arg == ss->ss_arg){
+	if (ss == ssrm){
 	    *ss_prev = ss->ss_next;
 	    if (ss->ss_stream)
 		free(ss->ss_stream);
@@ -270,8 +281,56 @@ stream_cb_delete(clicon_handle     h,
 	}
 	ss_prev = &ss->ss_next;
     }
+    return 0;
+}
+
+/*! Remove stream subscription identified with fn and arg
+ */
+int
+stream_cb_delete(clicon_handle     h,
+		 char             *stream,
+		 stream_fn_t       fn,
+		 void             *arg)
+{
+    int                          retval = -1;
+    event_stream_t              *es;
+    struct stream_subscription  *ss;
+    
+    for (es=clicon_stream(h); es; es=es->es_next){
+	if (stream && strcmp(stream, es->es_name)!=0)
+	    continue;
+	for (ss = es->es_subscription; ss; ss = ss->ss_next){
+	    if (fn == ss->ss_fn && arg == ss->ss_arg){
+		if (stream_cb_rm(es, ss) < 0)
+		    goto done;
+		break; /* scb_rm removes element, must break - but only one match */
+	    }
+	}
     }
     retval = 0;
+ done:
+    return retval;
+}
+
+/*! Check if any stream subscriptions have timed out, if so remove them
+ */
+int
+stream_cb_timeout(event_stream_t   *es,
+    		  struct timeval   *tv)
+{
+    int                          retval = -1;
+    struct stream_subscription  *ss;
+
+ again: /* If we remove must start again */
+    for (ss = es->es_subscription; ss; ss = ss->ss_next){
+	if (timerisset(&ss->ss_stoptime) && timercmp(&ss->ss_stoptime, tv, <)){
+	    if (stream_cb_rm(es, ss) < 0)
+		goto done;
+	    goto again;
+	}
+    }
+    retval = 0;
+ done:
     return retval;
 }
 
@@ -285,25 +344,22 @@ stream_cb_delete(clicon_handle     h,
  */
 int
 stream_notify_xml(clicon_handle   h, 
-		  char         *stream, 
+		  event_stream_t *es,
 		  cxobj          *xevent)
 {
     int                         retval = -1;
-    event_stream_t             *es;
     struct stream_subscription *ss;
     
     clicon_debug(1, "%s", __FUNCTION__);
-    if ((es = stream_find(h, stream)) == NULL)
-	goto ok;
     /* Go thru all global (handle) subscriptions and find matches */
     for (ss = es->es_subscription; ss; ss = ss->ss_next){
+	/* Check if this is of interest, ie not larger than stoptime? */
 	if (ss->ss_xpath == NULL ||
 	    strlen(ss->ss_xpath)==0 ||
 	    xpath_first(xevent, "%s", ss->ss_xpath) != NULL)
 	    if ((*ss->ss_fn)(h, xevent, ss->ss_arg) < 0)
 		goto done;
     }
- ok:
     retval = 0;
   done:
     return retval;
@@ -335,8 +391,11 @@ stream_notify(clicon_handle h,
     cbuf      *cb = NULL;
     char       timestr[27];
     struct timeval tv;
+    event_stream_t *es;
 
     clicon_debug(1, "%s", __FUNCTION__);
+    if ((es = stream_find(h, stream)) == NULL)
+	goto ok;
     va_start(args, event);
     len = vsnprintf(NULL, 0, event, args) + 1;
     va_end(args);
@@ -352,12 +411,18 @@ stream_notify(clicon_handle h,
 	clicon_err(OE_YANG, 0, "No yang spec");
 	goto done;
     }
+    gettimeofday(&tv, NULL);
+#if 1
+    /* Go thru callbacks and see if any have timed out, if so remove them 
+     * Could also be done by a separate timer.
+     */
+    if (stream_cb_timeout(es, &tv) < 0)
+	goto done;
+#endif
     if ((cb = cbuf_new()) == NULL){
 	clicon_err(OE_UNIX, errno, "cbuf_new");
 	goto done;
     }
-
-    gettimeofday(&tv, NULL);
     if (time2str(tv, timestr, sizeof(timestr)) < 0){
 	clicon_err(OE_UNIX, errno, "time2str");
 	goto done;
@@ -367,8 +432,14 @@ stream_notify(clicon_handle h,
 	goto done;
     if (xml_rootchild(xev, 0, &xev) < 0)
 	goto done;
-    if (stream_notify_xml(h, stream, xev) < 0)
+    if (stream_notify_xml(h, es, xev) < 0)
 	goto done;
+    if (es->es_replay_enabled){
+	if (stream_replay_add(es, &tv, xev) < 0)
+	    goto done;
+	xev = NULL; /* xml stored in replay_add and should not be freed */
+    }
+ ok:
     retval = 0;
   done:
     if (cb)
@@ -380,7 +451,105 @@ stream_notify(clicon_handle h,
     return retval;
 }
 
+
+/*! Replay a stream
+ *  Start Time:
+         A parameter, <startTime>, used to trigger the replay feature
+         and indicate that the replay should start at the time
+         specified.  If <startTime> is not present, this is not a replay
+         subscription.  It is not valid to specify start times that are
+         later than the current time.  If the <startTime> specified is
+         earlier than the log can support, the replay will begin with
+         the earliest available notification.  This parameter is of type
+         dateTime and compliant to [RFC3339].  Implementations must
+         support time zones.
+
+    Stop Time:
+         An optional parameter, <stopTime>, used with the optional
+         replay feature to indicate the newest notifications of
+         interest.  If <stopTime> is not present, the notifications will
+         continue until the subscription is terminated.  Must be used
+         with and be later than <startTime>.  Values of <stopTime> in
+         the future are valid.  This parameter is of type dateTime and
+         compliant to [RFC3339].  Implementations must support time
+         zones.
+	 
+ * Should we fork??
+ * Assume no future sample timestamps.
+ */
+int
+stream_replay(clicon_handle   h,
+	      char           *stream,
+	      struct timeval *start,
+	      struct timeval *stop)
+{
+    int             retval = -1;
+    event_stream_t *es;
+    struct stream_replay *r;
+
+    if ((es = stream_find(h, stream)) == NULL){
+	clicon_err(OE_CFG, ENOENT, "Stream %s not found", stream);
+	goto done;
+    }
+    if (!es->es_replay_enabled)
+	goto ok;
+    if ((r = es->es_replay) == NULL)
+	goto ok;
+    /* First loop to skip until start */
+    if (start){
+	do {
+	    if (timercmp(&r->r_tv, start, >=))
+		break;
+	    r = NEXTQ(struct stream_replay *, r);
+	} while (r && r!=es->es_replay);
+	if (r == NULL)
+	    goto ok;
+    }
+    /* Then notify until stop */
+    do {
+	if (stop && timercmp(&r->r_tv, stop, >))
+	    break;
+	if (stream_notify_xml(h, es, r->r_xml) < 0)
+	    goto done;
+	r = NEXTQ(struct stream_replay *, r);
+    } while (r && r!=es->es_replay);
+ ok:
+    retval = 0;
+ done:
+    return retval;
+}
+
+/*! Add replay sample to stream with timestamp
+ * @param[in] es   Stream
+ * @param[in] tv   Timestamp
+ * @param[in] xv   XML
+ */
+int
+stream_replay_add(event_stream_t *es,
+		  struct timeval *tv,
+		  cxobj          *xv)
+{
+    int                   retval = -1;
+    struct stream_replay *new;
+
+    if ((new = malloc(sizeof *new)) == NULL){
+	clicon_err(OE_UNIX, errno, "malloc");
+	goto done;
+    }
+    memset(new, 0, (sizeof *new));
+    new->r_tv = *tv;
+    new->r_xml = xv;
+    ADDQ(new, es->es_replay);
+    retval = 0;
+ done:
+    return retval;
+}
+
 #ifdef CLIXON_PUBLISH_STREAMS
+/* SSE support using Nginx Nchan. This code needs to be enabled at configure 
+ * time using: --enable-publish configure option
+ * It uses CURL and autoconf needs to set that dependency
+ */
 
 #include <curl/curl.h>
 
@@ -412,7 +581,6 @@ curl_get_cb(void *ptr,
     memcpy(buf->b_buf+buf->b_len, ptr, len);
     buf->b_len += len;
     buf->b_buf[buf->b_len] = '\0';
-    fprintf(stderr, "%s: %s\n", __FUNCTION__, buf->b_buf);
     return len;
 }
 
@@ -581,5 +749,3 @@ stream_publish_exit()
 #endif 
     return 0;
 }
-
-

test/test_stream.sh

@@ -139,6 +139,7 @@ fi
 # Netconf stream subscription
 # Switch here since subscriptions takes time
 if true; then
+
 new "netconf EXAMPLE subscription"
 expectwait "$clixon_netconf -qf $cfg -y $fyang" '<rpc><create-subscription><stream>EXAMPLE</stream></create-subscription></rpc>]]>]]>' '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
 
@@ -152,6 +153,9 @@ new "netconf NONEXIST subscription"
 expectwait "$clixon_netconf -qf $cfg -y $fyang" '<rpc><create-subscription><stream>NONEXIST</stream></create-subscription></rpc>]]>]]>' '^<rpc-reply><rpc-error><error-tag>invalid-value</error-tag><error-type>application</error-type><error-severity>error</error-severity><error-message>No such stream</error-message></rpc-error></rpc-reply>]]>]]>$' 5
 fi
 
+#new "netconf EXAMPLE subscription with replay"
+#expectwait "$clixon_netconf -qf $cfg -y $fyang" '<rpc><create-subscription><stream>EXAMPLE</stream><startTime>2018-10-21T19:22:16</startTime><stopTime>2018-10-21T19:25:00</stopTime></create-subscription></rpc>]]>]]>' '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
+
 new "Kill restconf daemon"
 sudo pkill -u www-data clixon_restconf