Add coordination between AMI and AGI applications, with an asyncagi method

Feature proposed and patched by: moy
(Closes issue #11282)


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@96174 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 391 insertions, 3 deletions

diff --git a/res/res_agi.c b/res/res_agi.c
index 6fa0d7d35..9a637c46a 100644
--- a/res/res_agi.c
+++ b/res/res_agi.c
@@ -52,6 +52,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/lock.h"
 #include "asterisk/strings.h"
 #include "asterisk/agi.h"
+#include "asterisk/manager.h"
 #include "asterisk/version.h"
 #include "asterisk/speech.h"
 #include "asterisk/manager.h"
@@ -101,6 +102,7 @@ static int agidebug = 0;
 enum agi_result {
 	AGI_RESULT_SUCCESS,
 	AGI_RESULT_SUCCESS_FAST,
+	AGI_RESULT_SUCCESS_ASYNC,
 	AGI_RESULT_FAILURE,
 	AGI_RESULT_NOTFOUND,
 	AGI_RESULT_HANGUP,
@@ -140,6 +142,373 @@ int ast_agi_fdprintf(struct ast_channel *chan, int fd, char *fmt, ...)
 	return ast_carefulwrite(fd, buf->str, buf->used, 100);
 }
 
+/* linked list of AGI commands ready to be executed by Async AGI */
+struct agi_cmd {
+	char *cmd_buffer;
+	char *cmd_id;
+	AST_LIST_ENTRY(agi_cmd) entry;
+};
+
+static void free_agi_cmd(struct agi_cmd *cmd)
+{
+	ast_free(cmd->cmd_buffer);
+	ast_free(cmd->cmd_id);
+	ast_free(cmd);
+}
+
+/* AGI datastore destructor */
+static void agi_destroy_commands_cb(void *data)
+{
+	struct agi_cmd *cmd;
+	AST_LIST_HEAD(, agi_cmd) *chan_cmds = data;
+	AST_LIST_LOCK(chan_cmds);
+	while ( (cmd = AST_LIST_REMOVE_HEAD(chan_cmds, entry)) ) { 
+		free_agi_cmd(cmd);
+	} 
+	AST_LIST_UNLOCK(chan_cmds);
+	AST_LIST_HEAD_DESTROY(chan_cmds);
+	ast_free(chan_cmds);
+}
+
+/* channel datastore to keep the queue of AGI commands in the channel */
+static const struct ast_datastore_info agi_commands_datastore_info = {
+	.type = "AsyncAGI",
+	.destroy = agi_destroy_commands_cb
+};
+
+static const char mandescr_asyncagi[] =
+"Description: Add an AGI command to the execute queue of the channel in Async AGI\n"
+"Variables:\n"
+"  *Channel: Channel that is currently in Async AGI\n"
+"  *Command: Application to execute\n"
+"   CommandID: comand id. This will be sent back in CommandID header of AsyncAGI exec event notification\n"
+"\n";
+
+static struct agi_cmd *get_agi_cmd(struct ast_channel *chan)
+{
+	struct ast_datastore *store;
+	struct agi_cmd *cmd;
+	AST_LIST_HEAD(, agi_cmd) *agi_commands;
+
+	ast_channel_lock(chan);
+	store = ast_channel_datastore_find(chan, &agi_commands_datastore_info, NULL);
+	ast_channel_unlock(chan);
+	if (!store) {
+		ast_log(LOG_ERROR, "Hu? datastore disappeared at Async AGI on Channel %s!\n", chan->name);
+		return NULL;
+	}
+	agi_commands = store->data;
+	AST_LIST_LOCK(agi_commands);
+	cmd = AST_LIST_REMOVE_HEAD(agi_commands, entry);
+	AST_LIST_UNLOCK(agi_commands);
+	return cmd;
+}
+
+/* channel is locked when calling this one either from the CLI or manager thread */
+static int add_agi_cmd(struct ast_channel *chan, const char *cmd_buff, const char *cmd_id)
+{
+	struct ast_datastore *store;
+	struct agi_cmd *cmd;
+	AST_LIST_HEAD(, agi_cmd) *agi_commands;
+
+	store = ast_channel_datastore_find(chan, &agi_commands_datastore_info, NULL);
+	if (!store) {
+		ast_log(LOG_WARNING, "Channel %s is not at Async AGI.\n", chan->name);
+		return -1;
+	}
+	agi_commands = store->data;
+	cmd = ast_calloc(1, sizeof(*cmd));
+	if (!cmd) {
+		return -1;
+	}
+	cmd->cmd_buffer = ast_strdup(cmd_buff);
+	if (!cmd->cmd_buffer) {
+		ast_free(cmd);
+		return -1;
+	}
+	cmd->cmd_id = ast_strdup(cmd_id);
+	if (!cmd->cmd_id) {
+		ast_free(cmd->cmd_buffer);
+		ast_free(cmd);
+		return -1;
+	}
+	AST_LIST_LOCK(agi_commands);
+	AST_LIST_INSERT_TAIL(agi_commands, cmd, entry);
+	AST_LIST_UNLOCK(agi_commands);
+	return 0;
+}
+
+static int add_to_agi(struct ast_channel *chan)
+{
+	struct ast_datastore *datastore;
+	AST_LIST_HEAD(, agi_cmd) *agi_cmds_list;
+
+	/* check if already on AGI */
+	ast_channel_lock(chan);
+	datastore = ast_channel_datastore_find(chan, &agi_commands_datastore_info, NULL);
+	ast_channel_unlock(chan);
+	if (datastore) {
+		/* we already have an AGI datastore, let's just 
+		   return success */
+		return 0;
+	}
+
+	/* the channel has never been on Async AGI,
+	   let's allocate it's datastore */
+	datastore = ast_channel_datastore_alloc(&agi_commands_datastore_info, "AGI");
+	if (!datastore) {
+		return -1;
+	}
+	agi_cmds_list = ast_calloc(1, sizeof(*agi_cmds_list));
+	if (!agi_cmds_list) {
+		ast_log(LOG_ERROR, "Unable to allocate Async AGI commands list.\n");
+		ast_channel_datastore_free(datastore);
+		return -1;
+	}
+	datastore->data = agi_cmds_list;
+	AST_LIST_HEAD_INIT(agi_cmds_list);
+	ast_channel_lock(chan);
+	ast_channel_datastore_add(chan, datastore);
+	ast_channel_unlock(chan);
+	return 0;
+}
+
+/*!
+ * \brief CLI command to add applications to execute in Async AGI 
+ * \param e
+ * \param cmd 
+ * \param a
+ *
+ * \retval CLI_SUCCESS on success
+ * \retval NULL when init or tab completion is used
+*/
+static char *handle_cli_agi_add_cmd(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct ast_channel *chan;
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "agi exec";
+		e->usage = "Usage: agi exec <channel name> <app and arguments> [id]\n"
+			   "       Add AGI command to the execute queue of the specified channel in Async AGI\n";
+		return NULL;
+	case CLI_GENERATE:
+		if (a->pos == 2)
+			return ast_complete_channels(a->line, a->word, a->pos, a->n, 2);
+		return NULL;
+	}
+
+	if (a->argc < 4)
+		return CLI_SHOWUSAGE;
+	chan = ast_get_channel_by_name_locked(a->argv[2]);
+	if (!chan) {
+		ast_log(LOG_WARNING, "Channel %s does not exists or cannot lock it\n", a->argv[2]);
+		return CLI_FAILURE;
+	}
+	if (add_agi_cmd(chan, a->argv[3], (a->argc > 4 ? a->argv[4] : ""))) {
+		ast_log(LOG_WARNING, "failed to add AGI command to queue of channel %s\n", chan->name);
+		ast_channel_unlock(chan);
+		return CLI_FAILURE;
+	}
+	ast_log(LOG_DEBUG, "Added AGI command to channel %s queue\n", chan->name);
+	ast_channel_unlock(chan);
+	return CLI_SUCCESS;
+}
+
+/*!
+ * \brief Add a new command to execute by the Async AGI application
+ * \param s
+ * \param m
+ *
+ * It will append the application to the specified channel's queue
+ * if the channel is not inside Async AGI application it will return an error
+ * \retval 0 on success or incorrect use
+ * \retval 1 on failure to add the command ( most likely because the channel 
+ * is not in Async AGI loop )
+*/
+static int action_add_agi_cmd(struct mansession *s, const struct message *m)
+{
+	const char *channel = astman_get_header(m, "Channel");
+	const char *cmdbuff = astman_get_header(m, "Command");
+	const char *cmdid   = astman_get_header(m, "CommandID");
+	struct ast_channel *chan;
+	char buf[256];
+	if (ast_strlen_zero(channel) || ast_strlen_zero(cmdbuff)) {
+		astman_send_error(s, m, "Both, Channel and Command are *required*");
+		return 0;
+	}
+	chan = ast_get_channel_by_name_locked(channel);
+	if (!chan) {
+		snprintf(buf, sizeof(buf), "Channel %s does not exists or cannot get its lock", channel);
+		astman_send_error(s, m, buf);
+		return 1;
+	}
+	if (add_agi_cmd(chan, cmdbuff, cmdid)) {
+		snprintf(buf, sizeof(buf), "Failed to add AGI command to channel %s queue", chan->name);
+		astman_send_error(s, m, buf);
+		ast_channel_unlock(chan);
+		return 1;
+	}
+	astman_send_ack(s, m, "Added AGI command to queue");
+	ast_channel_unlock(chan);
+	return 0;
+}
+
+static int agi_handle_command(struct ast_channel *chan, AGI *agi, char *buf, int dead);
+static void setup_env(struct ast_channel *chan, char *request, int fd, int enhanced, int argc, char *argv[]);
+static enum agi_result launch_asyncagi(struct ast_channel *chan, char *argv[], int *efd)
+{
+/* This buffer sizes might cause truncation if the AGI command writes more data
+   than AGI_BUF_SIZE as result. But let's be serious, is there an AGI command 
+   that writes a response larger than 1024 bytes?, I don't think so, most of 
+   them are just result=blah stuff. However probably if GET VARIABLE is called 
+   and the variable has large amount of data, that could be a problem. We could 
+   make this buffers dynamic, but let's leave that as a second step.
+
+   AMI_BUF_SIZE is twice AGI_BUF_SIZE just for the sake of choosing a safe 
+   number. Some characters of AGI buf will be url encoded to be sent to manager 
+   clients.  An URL encoded character will take 3 bytes, but again, to cause 
+   truncation more than about 70% of the AGI buffer should be URL encoded for 
+   that to happen.  Not likely at all. 
+
+   On the other hand. I wonder if read() could eventually return less data than 
+   the amount already available in the pipe? If so, how to deal with that?  
+   So far, my tests on Linux have not had any problems.
+ */
+#define AGI_BUF_SIZE 1024
+#define AMI_BUF_SIZE 2048
+	struct ast_frame *f;
+	struct agi_cmd *cmd;
+	int res, fds[2];
+	int timeout = 100; 
+	char agi_buffer[AGI_BUF_SIZE + 1];
+	char ami_buffer[AMI_BUF_SIZE];
+	enum agi_result returnstatus = AGI_RESULT_SUCCESS_ASYNC;
+	AGI async_agi;
+
+	if (efd) {
+		ast_log(LOG_WARNING, "Async AGI does not support Enhanced AGI yet\n");
+		return AGI_RESULT_FAILURE;
+	}
+
+	/* add AsyncAGI datastore to the channel */
+	if (add_to_agi(chan)) {
+		ast_log(LOG_ERROR, "failed to start Async AGI on channel %s\n", chan->name);
+		return AGI_RESULT_FAILURE;
+	}	
+
+	/* this pipe allows us to create a "fake" AGI struct to use 
+	   the AGI commands */
+	res = pipe(fds);
+	if (res) {
+		ast_log(LOG_ERROR, "failed to create Async AGI pipe\n");
+		/* intentionally do not remove datastore, added with 
+		   add_to_agi(), from channel. It will be removed when 
+		   the channel is hung up anyways */
+		return AGI_RESULT_FAILURE;
+	}
+	/* handlers will get the pipe write fd and we read the AGI responses 
+	   from the pipe read fd */
+	async_agi.fd = fds[1]; 
+	async_agi.ctrl = fds[1];
+	async_agi.audio = -1; /* no audio support */
+	async_agi.fast = 0;
+
+	/* notify possible manager users of a new channel ready to 
+	   receive commands */	
+	setup_env(chan, "async", fds[1], 0, 0, NULL);
+	/* read the environment */
+	res = read(fds[0], agi_buffer, AGI_BUF_SIZE);
+	if (!res) {
+		ast_log(LOG_ERROR, "failed to read from Async AGI pipe on channel %s\n", chan->name);
+		returnstatus = AGI_RESULT_FAILURE;
+		goto quit;
+	}
+	agi_buffer[res] = '\0';
+	/* encode it and send it thru the manager so whoever is going to take 
+	   care of AGI commands on this channel can decide which AGI commands 
+	   to execute based on the setup info */
+	ast_uri_encode(agi_buffer, ami_buffer, AMI_BUF_SIZE, 1);
+	manager_event(EVENT_FLAG_CALL, "AsyncAGI", "SubEvent: Start\r\nChannel: %s\r\nEnv: %s\r\n", chan->name, ami_buffer); 
+	while (1) {
+		/* bail out if we need to hangup */
+		if (ast_check_hangup(chan)) {
+			ast_log(LOG_DEBUG, "ast_check_hangup returned true on chan %s\n", chan->name);
+			break;
+		}
+		/* retrieve a command 
+		   (commands are added via the manager or the cli threads) */
+		cmd = get_agi_cmd(chan);
+		if (cmd) {
+			/* OK, we have a command, let's call the 
+			   command handler. */
+			res = agi_handle_command(chan, &async_agi, cmd->cmd_buffer, 0);
+			if ((res < 0) || (res == AST_PBX_KEEPALIVE)) {
+				free_agi_cmd(cmd);
+				break;
+			}
+			/* the command handler must have written to our fake 
+			   AGI struct fd (the pipe), let's read the response */
+			res = read(fds[0], agi_buffer, AGI_BUF_SIZE);
+			if (!res) {
+				returnstatus = AGI_RESULT_FAILURE;
+				ast_log(LOG_ERROR, "failed to read from AsyncAGI pipe on channel %s\n", chan->name);
+				free_agi_cmd(cmd);
+				break;
+			}
+			/* we have a response, let's send the response thru the
+			   manager. Include the CommandID if it was specified 
+			   when the command was added */
+			agi_buffer[res] = '\0';
+			ast_uri_encode(agi_buffer, ami_buffer, AMI_BUF_SIZE, 1);
+			if (ast_strlen_zero(cmd->cmd_id))
+				manager_event(EVENT_FLAG_CALL, "AsyncAGI", "SubEvent: Exec\r\nChannel: %s\r\nResult: %s\r\n", chan->name, ami_buffer);
+			else
+				manager_event(EVENT_FLAG_CALL, "AsyncAGI", "SubEvent: Exec\r\nChannel: %s\r\nCommandID: %s\r\nResult: %s\r\n", chan->name, cmd->cmd_id, ami_buffer);
+			free_agi_cmd(cmd);
+		} else {
+			/* no command so far, wait a bit for a frame to read */
+			res = ast_waitfor(chan, timeout);
+			if (res < 0) {
+				ast_log(LOG_DEBUG, "ast_waitfor returned <= 0 on chan %s\n", chan->name);
+				break;
+			}
+			if (res == 0)
+				continue;
+			f = ast_read(chan);
+			if (!f) {
+				ast_log(LOG_DEBUG, "No frame read on channel %s, going out ...\n", chan->name);
+				returnstatus = AGI_RESULT_HANGUP;
+				break;
+			}
+			/* is there any other frame we should care about 
+			   besides AST_CONTROL_HANGUP? */
+			if (f->frametype == AST_FRAME_CONTROL && f->subclass == AST_CONTROL_HANGUP) {
+				ast_log(LOG_DEBUG, "Got HANGUP frame on channel %s, going out ...\n", chan->name);
+				ast_frfree(f);
+				break;
+			}
+			ast_frfree(f);
+		}
+	}
+quit:
+	/* notify manager users this channel cannot be 
+	   controlled anymore by Async AGI */
+	manager_event(EVENT_FLAG_CALL, "AsyncAGI", "SubEvent: End\r\nChannel: %s\r\n", chan->name);
+
+	/* close the pipe */
+	close(fds[0]);
+	close(fds[1]);
+
+	/* intentionally don't get rid of the datastore. So commands can be 
+	   still in the queue in case AsyncAGI gets called again.
+	   Datastore destructor will be called on channel destroy anyway  */
+
+	return returnstatus;
+
+#undef AGI_BUF_SIZE 
+#undef AMI_BUF_SIZE 
+}
+
 /* launch_netscript: The fastagi handler.
 	FastAGI defaults to port 4573 */
 static enum agi_result launch_netscript(char *agiurl, char *argv[], int *fds, int *efd, int *opid)
@@ -230,7 +599,7 @@ static enum agi_result launch_netscript(char *agiurl, char *argv[], int *fds, in
 	return AGI_RESULT_SUCCESS_FAST;
 }
 
-static enum agi_result launch_script(char *script, char *argv[], int *fds, int *efd, int *opid)
+static enum agi_result launch_script(struct ast_channel *chan, char *script, char *argv[], int *fds, int *efd, int *opid)
 {
 	char tmp[256];
 	int pid, toast[2], fromast[2], audio[2], x, res;
@@ -239,6 +608,8 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 
 	if (!strncasecmp(script, "agi://", 6))
 		return launch_netscript(script, argv, fds, efd, opid);
+	if (!strncasecmp(script, "agi:async", sizeof("agi:async")-1))
+		return launch_asyncagi(chan, argv, efd);
 	
 	if (script[0] != '/') {
 		snprintf(tmp, sizeof(tmp), "%s/%s", ast_config_AST_AGI_DIR, script);
@@ -1628,6 +1999,12 @@ static int handle_speechrecognize(struct ast_channel *chan, AGI *agi, int argc,
 	return RESULT_SUCCESS;
 }
 
+static int handle_asyncagi_break(struct ast_channel *chan, AGI *agi, int argc, char *argv[])
+{
+	ast_agi_fdprintf(chan, agi->fd, "200 result=0\n");
+	return AST_PBX_KEEPALIVE;
+}
+
 static char usage_setmusic[] =
 " Usage: SET MUSIC ON <on|off> <class>\n"
 "	Enables/Disables the music on hold generator.  If <class> is\n"
@@ -1871,6 +2248,10 @@ static char usage_autohangup[] =
 " future.  Of course it can be hungup before then as well. Setting to 0 will\n"
 " cause the autohangup feature to be disabled on this channel.\n";
 
+static char usage_break_aagi[] =
+" Usage: ASYNCAGI BREAK\n"
+"	Break the Async AGI loop.\n";
+
 static char usage_noop[] =
 " Usage: NoOp\n"
 "	Does nothing.\n";
@@ -1956,6 +2337,7 @@ static struct agi_command commands[] = {
 	{ { "speech", "activate", "grammar", NULL }, handle_speechactivategrammar, "Activates a grammar", usage_speechactivategrammar, 0 },
 	{ { "speech", "deactivate", "grammar", NULL }, handle_speechdeactivategrammar, "Deactivates a grammar", usage_speechdeactivategrammar, 0 },
 	{ { "speech", "recognize", NULL }, handle_speechrecognize, "Recognizes speech", usage_speechrecognize, 0 },
+	{ { "asyncagi", "break", NULL }, handle_asyncagi_break, "Break AsyncAGI loop", usage_break_aagi, 0 },
 };
 
 static AST_RWLIST_HEAD_STATIC(agi_commands, agi_command);
@@ -2500,7 +2882,9 @@ static int agi_exec_full(struct ast_channel *chan, void *data, int enhanced, int
 		}
 	}
 #endif
-	res = launch_script(args.argv[0], args.argv, fds, enhanced ? &efd : NULL, &pid);
+	res = launch_script(chan, args.argv[0], args.argv, fds, enhanced ? &efd : NULL, &pid);
+	/* Async AGI do not require run_agi(), so just proceed if normal AGI
+	   or Fast AGI are setup with success. */
 	if (res == AGI_RESULT_SUCCESS || res == AGI_RESULT_SUCCESS_FAST) {
 		int status = 0;
 		agi.fd = fds[1];
@@ -2516,12 +2900,13 @@ static int agi_exec_full(struct ast_channel *chan, void *data, int enhanced, int
 		if (efd > -1)
 			close(efd);
 		ast_unreplace_sigchld();
-	}
+	} 
 	ast_module_user_remove(u);
 
 	switch (res) {
 	case AGI_RESULT_SUCCESS:
 	case AGI_RESULT_SUCCESS_FAST:
+	case AGI_RESULT_SUCCESS_ASYNC:
 		pbx_builtin_setvar_helper(chan, "AGISTATUS", "SUCCESS");
 		break;
 	case AGI_RESULT_FAILURE:
@@ -2575,6 +2960,7 @@ static int deadagi_exec(struct ast_channel *chan, void *data)
 }
 
 static struct ast_cli_entry cli_agi[] = {
+	AST_CLI_DEFINE(handle_cli_agi_add_cmd,   "Add AGI command to a channel in Async AGI"),
 	AST_CLI_DEFINE(handle_cli_agi_debug,    "Enable/Disable AGI debugging"),
 	AST_CLI_DEFINE(handle_cli_agi_show,     "List AGI commands or specific help"),
 	AST_CLI_DEFINE(handle_cli_agi_dumphtml, "Dumps a list of AGI commands in HTML format")
@@ -2586,6 +2972,7 @@ static int unload_module(void)
 	ast_agi_unregister_multiple(ast_module_info->self, commands, sizeof(commands) / sizeof(struct agi_command));
 	ast_unregister_application(eapp);
 	ast_unregister_application(deadapp);
+	ast_manager_unregister("AGI");
 	return ast_unregister_application(app);
 }
 
@@ -2595,6 +2982,7 @@ static int load_module(void)
 	ast_agi_register_multiple(ast_module_info->self, commands, sizeof(commands) / sizeof(struct agi_command));
 	ast_register_application(deadapp, deadagi_exec, deadsynopsis, descrip);
 	ast_register_application(eapp, eagi_exec, esynopsis, descrip);
+	ast_manager_register2("AGI", EVENT_FLAG_CALL, action_add_agi_cmd, "Add an AGI command to execute by Async AGI", mandescr_asyncagi);
 	return ast_register_application(app, agi_exec, synopsis, descrip);
 }