app_queue: Add QueueWithdrawCaller AMI action

This adds a new AMI action called QueueWithdrawCaller.
This AMI action makes it possible to withdraw a caller from a queue,
in a safe and a generic manner.
This can be useful for retrieving a specific call and
dispatching it to a specific extension.
It works by signaling the caller to exit the queue application
whenever it can. Therefore, it is not guaranteed
that the call will leave the queue.

ASTERISK-29909 #close

Change-Id: Ic15aa238e23b2884abdcaadff2fda7679e29b7ec

diff --git a/apps/app_queue.c b/apps/app_queue.c
index 8ec98e23e0ace3962f0b335655bb1873f2fb2623..35054130a437d00fae694a1a65fcc1a8efe963e0 100644 (file)
--- a/apps/app_queue.c
+++ b/apps/app_queue.c
@@ -290,6 +290,7 @@
                                        <value name="JOINUNAVAIL" />
                                        <value name="LEAVEUNAVAIL" />
                                        <value name="CONTINUE" />
+                                       <value name="WITHDRAW" />
                                </variable>
                                <variable name="ABANDONED">
                                        <para>If the call was not answered by an agent this variable will be TRUE.</para>
@@ -298,6 +299,9 @@
                                <variable name="DIALEDPEERNUMBER">
                                        <para>Resource of the agent that was dialed set on the outbound channel.</para>
                                </variable>
+                               <variable name="QUEUE_WITHDRAW_INFO">
+                                       <para>If the call was successfully withdrawn from the queue, and the withdraw request was provided with optional withdraw info, the withdraw info will be stored in this variable.</para>
+                               </variable>
                        </variablelist>
                </description>
                <see-also>
@@ -1057,6 +1061,25 @@
                <description>
                </description>
        </manager>
+       <manager name="QueueWithdrawCaller" language="en_US">
+               <synopsis>
+                       Request to withdraw a caller from the queue back to the dialplan.
+               </synopsis>
+               <syntax>
+                       <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
+                       <parameter name="Queue" required="true">
+                               <para>The name of the queue to take action on.</para>
+                       </parameter>
+                       <parameter name="Caller" required="true">
+                               <para>The caller (channel) to withdraw from the queue.</para>
+                       </parameter>
+                       <parameter name="WithdrawInfo" required="false">
+                               <para>Optional info to store. If the call is successfully withdrawn from the queue, this information will be available in the QUEUE_WITHDRAW_INFO variable.</para>
+                       </parameter>
+               </syntax>
+               <description>
+               </description>
+       </manager>
 
        <managerEvent language="en_US" name="QueueParams">
                <managerEventInstance class="EVENT_FLAG_AGENT">
@@ -1602,6 +1625,7 @@ enum queue_result {
        QUEUE_LEAVEUNAVAIL = 5,
        QUEUE_FULL = 6,
        QUEUE_CONTINUE = 7,
+       QUEUE_WITHDRAW = 8,
 };
 
 static const struct {
@@ -1616,6 +1640,7 @@ static const struct {
        { QUEUE_LEAVEUNAVAIL, "LEAVEUNAVAIL" },
        { QUEUE_FULL, "FULL" },
        { QUEUE_CONTINUE, "CONTINUE" },
+       { QUEUE_WITHDRAW, "WITHDRAW" },
 };
 
 enum queue_timeout_priority {
@@ -1684,6 +1709,8 @@ struct queue_ent {
        time_t start;                          /*!< When we started holding */
        time_t expire;                         /*!< When this entry should expire (time out of queue) */
        int cancel_answered_elsewhere;         /*!< Whether we should force the CAE flag on this call (C) option*/
+       unsigned int withdraw:1;               /*!< Should this call exit the queue at its next iteration? Used for QueueWithdrawCaller */
+       char *withdraw_info;                   /*!< Optional info passed by the caller of QueueWithdrawCaller */
        struct ast_channel *chan;              /*!< Our channel */
        AST_LIST_HEAD_NOLOCK(,penalty_rule) qe_rules; /*!< Local copy of the queue's penalty rules */
        struct penalty_rule *pr;               /*!< Pointer to the next penalty rule to implement */
@@ -5802,6 +5829,13 @@ static int wait_our_turn(struct queue_ent *qe, int ringing, enum queue_result *r
        /* This is the holding pen for callers 2 through maxlen */
        for (;;) {
 
+               /* A request to withdraw this call from the queue arrived */
+               if (qe->withdraw) {
+                       *reason = QUEUE_WITHDRAW;
+                       res = 1;
+                       break;
+               }
+
                if (is_our_turn(qe)) {
                        break;
                }
@@ -7622,6 +7656,51 @@ static int change_priority_caller_on_queue(const char *queuename, const char *ca
 }
 
 
+/*! \brief Request to withdraw a caller from a queue
+ * \retval RES_NOSUCHQUEUE queue does not exist
+ * \retval RES_OKAY withdraw request sent
+ * \retval RES_NOT_CALLER queue exists but no caller
+ * \retval RES_EXISTS a withdraw request was already sent for this caller (channel) and queue
+*/
+static int request_withdraw_caller_from_queue(const char *queuename, const char *caller, const char *withdraw_info)
+{
+       struct call_queue *q;
+       struct queue_ent *qe;
+       int res = RES_NOSUCHQUEUE;
+
+       /*! \note Ensure the appropriate realtime queue is loaded.  Note that this
+        * short-circuits if the queue is already in memory. */
+       if (!(q = find_load_queue_rt_friendly(queuename))) {
+               return res;
+       }
+
+       ao2_lock(q);
+       res = RES_NOT_CALLER;
+       for (qe = q->head; qe; qe = qe->next) {
+               if (!strcmp(ast_channel_name(qe->chan), caller)) {
+                       if (qe->withdraw) {
+                               ast_debug(1, "Ignoring duplicate withdraw request of caller %s from queue %s\n", caller, queuename);
+                               res = RES_EXISTS;
+                       } else {
+                               ast_debug(1, "Requested withdraw of caller %s from queue %s\n", caller, queuename);
+                               /* It is not possible to change the withdraw info by further withdraw requests for this caller (channel)
+                                  in this queue, so we do not need to worry about a memory leak here. */
+                               if (withdraw_info) {
+                                       qe->withdraw_info = ast_strdup(withdraw_info);
+                               }
+                               qe->withdraw = 1;
+                               res = RES_OKAY;
+                       }
+                       break;
+               }
+       }
+       ao2_unlock(q);
+       queue_unref(q);
+
+       return res;
+}
+
+
 static int publish_queue_member_pause(struct call_queue *q, struct member *member)
 {
        struct ast_json *json_blob = queue_member_blob_create(q, member);
@@ -8569,6 +8648,13 @@ check_turns:
                /* they may dial a digit from the queue context; */
                /* or, they may timeout. */
 
+               /* A request to withdraw this call from the queue arrived */
+               if (qe.withdraw) {
+                       reason = QUEUE_WITHDRAW;
+                       res = 1;
+                       break;
+               }
+
                /* Leave if we have exceeded our queuetimeout */
                if (qe.expire && (time(NULL) >= qe.expire)) {
                        record_abandoned(&qe);
@@ -8596,6 +8682,13 @@ check_turns:
                        }
                }
 
+               /* A request to withdraw this call from the queue arrived */
+               if (qe.withdraw) {
+                       reason = QUEUE_WITHDRAW;
+                       res = 1;
+                       break;
+               }
+
                /* Leave if we have exceeded our queuetimeout */
                if (qe.expire && (time(NULL) >= qe.expire)) {
                        record_abandoned(&qe);
@@ -8670,7 +8763,14 @@ check_turns:
 
 stop:
        if (res) {
-               if (res < 0) {
+               if (reason == QUEUE_WITHDRAW) {
+                       record_abandoned(&qe);
+                       ast_queue_log(qe.parent->name, ast_channel_uniqueid(qe.chan), "NONE", "WITHDRAW", "%d|%d|%ld|%.40s", qe.pos, qe.opos, (long) (time(NULL) - qe.start), qe.withdraw_info ? qe.withdraw_info : "");
+                       if (qe.withdraw_info) {
+                               pbx_builtin_setvar_helper(qe.chan, "QUEUE_WITHDRAW_INFO", qe.withdraw_info);
+                       }
+                       res = 0;
+               } else if (res < 0) {
                        if (!qe.handled) {
                                record_abandoned(&qe);
                                ast_queue_log(args.queuename, ast_channel_uniqueid(chan), "NONE", "ABANDON",
@@ -8690,6 +8790,13 @@ stop:
                }
        }
 
+       /* Free the optional withdraw info if present */
+       /* This is done here to catch all cases. e.g. if the call eventually wasn't withdrawn, e.g. answered */
+       if (qe.withdraw_info) {
+               ast_free(qe.withdraw_info);
+               qe.withdraw_info = NULL;
+       }
+
        /* Don't allow return code > 0 */
        if (res >= 0) {
                res = 0;
@@ -10743,6 +10850,41 @@ static int manager_change_priority_caller_on_queue(struct mansession *s, const s
        return 0;
 }
 
+static int manager_request_withdraw_caller_from_queue(struct mansession *s, const struct message *m)
+{
+       const char *queuename, *caller, *withdraw_info;
+
+       queuename = astman_get_header(m, "Queue");
+       caller = astman_get_header(m, "Caller");
+       withdraw_info = astman_get_header(m, "WithdrawInfo");
+
+       if (ast_strlen_zero(queuename)) {
+               astman_send_error(s, m, "'Queue' not specified.");
+               return 0;
+       }
+
+       if (ast_strlen_zero(caller)) {
+               astman_send_error(s, m, "'Caller' not specified.");
+               return 0;
+       }
+
+       switch (request_withdraw_caller_from_queue(queuename, caller, withdraw_info)) {
+       case RES_OKAY:
+               astman_send_ack(s, m, "Withdraw requested successfully");
+               break;
+       case RES_NOSUCHQUEUE:
+               astman_send_error(s, m, "Unable to request withdraw from queue: No such queue");
+               break;
+       case RES_NOT_CALLER:
+               astman_send_error(s, m, "Unable to request withdraw from queue: No such caller");
+               break;
+       case RES_EXISTS:
+               astman_send_error(s, m, "Unable to request withdraw from queue: Already requested");
+               break;
+       }
+
+       return 0;
+}
 
 
 static char *handle_queue_add_member(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
@@ -11472,6 +11614,7 @@ static int unload_module(void)
        ast_manager_unregister("QueueReset");
        ast_manager_unregister("QueueMemberRingInUse");
        ast_manager_unregister("QueueChangePriorityCaller");
+       ast_manager_unregister("QueueWithdrawCaller");
        ast_unregister_application(app_aqm);
        ast_unregister_application(app_rqm);
        ast_unregister_application(app_pqm);
@@ -11585,6 +11728,7 @@ static int load_module(void)
        err |= ast_manager_register_xml("QueueReload", 0, manager_queue_reload);
        err |= ast_manager_register_xml("QueueReset", 0, manager_queue_reset);
        err |= ast_manager_register_xml("QueueChangePriorityCaller", 0,  manager_change_priority_caller_on_queue);
+       err |= ast_manager_register_xml("QueueWithdrawCaller", 0,  manager_request_withdraw_caller_from_queue);
        err |= ast_custom_function_register(&queuevar_function);
        err |= ast_custom_function_register(&queueexists_function);
        err |= ast_custom_function_register(&queuemembercount_function);

diff --git a/doc/CHANGES-staging/queue_withdraw_caller.txt b/doc/CHANGES-staging/queue_withdraw_caller.txt
new file mode 100644 (file)
index 0000000..04e43d0
--- /dev/null
+++ b/doc/CHANGES-staging/queue_withdraw_caller.txt
@@ -0,0 +1,14 @@
+Subject: app_queue
+
+Added a new AMI action: QueueWithdrawCaller
+This AMI action makes it possible to withdraw a caller from a queue
+back to the dialplan. The call will be signaled to leave the queue
+whenever it can, hence, it not guaranteed that the call will leave
+the queue.
+
+Optional custom data can be passed in the request, in the WithdrawInfo
+parameter. If the call successfully withdrawn the queue,
+it can be retrieved using the QUEUE_WITHDRAW_INFO variable.
+
+This can be useful for certain uses, such as dispatching the call
+to a specific extension.