ctdb-logging: New option CTDB_LOGGING, remove CTDB_LOGFILE, CTDB_SYSLOG

Remove --logfile and --syslog daemon options and replace with
--logging.

Modularise and clean up logging initialisation code.  The
initialisation API includes an app_name argument that is currently
unused - this will be used in extensions to the syslog backend.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

4 files changed, 78 insertions, 30 deletions

diff --git a/ctdb/server/ctdb_logging.c b/ctdb/server/ctdb_logging.c
index bc47dd273fe..85dbfcfcc00 100644
--- a/ctdb/server/ctdb_logging.c
+++ b/ctdb/server/ctdb_logging.c
@@ -24,6 +24,13 @@
 #include "system/time.h"
 #include "system/filesys.h"
 #include "lib/util/debug.h"
+#include "lib/util/dlinklist.h"
+
+struct ctdb_log_backend {
+	struct ctdb_log_backend *prev, *next;
+	const char *prefix;
+	ctdb_log_setup_fn_t setup;
+};
 
 struct ctdb_log_state {
 	const char *prefix;
@@ -32,16 +39,34 @@ struct ctdb_log_state {
 	uint16_t buf_used;
 	void (*logfn)(const char *, uint16_t, void *);
 	void *logfn_private;
+	struct ctdb_log_backend *backends;
 };
 
-/* we need this global to keep the DEBUG() syntax */
+/* Used by ctdb_set_child_logging() */
 static struct ctdb_log_state *log_state;
 
-/*
-  choose the logfile location
-*/
-int ctdb_set_logfile(TALLOC_CTX *mem_ctx, const char *logfile, bool use_syslog)
+void ctdb_log_register_backend(const char *prefix, ctdb_log_setup_fn_t setup)
 {
+	struct ctdb_log_backend *b;
+
+	b = talloc_zero(log_state, struct ctdb_log_backend);
+	if (b == NULL) {
+		printf("Failed to register backend \"%s\" - no memory\n",
+		       prefix);
+		return;
+	}
+
+	b->prefix = prefix;
+	b->setup = setup;
+
+	DLIST_ADD_END(log_state->backends, b, NULL);
+}
+
+
+/* Initialise logging */
+bool ctdb_logging_init(TALLOC_CTX *mem_ctx, const char *logging)
+{
+	struct ctdb_log_backend *b;
 	int ret;
 
 	log_state = talloc_zero(mem_ctx, struct ctdb_log_state);
@@ -50,22 +75,26 @@ int ctdb_set_logfile(TALLOC_CTX *mem_ctx, const char *logfile, bool use_syslog)
 		abort();
 	}
 
-	if (use_syslog) {
-		ret = ctdb_log_setup_syslog();
-		if (ret != 0) {
-			printf("Setup of syslog logging failed with \"%s\"\n",
-			       strerror(ret));
-			abort();
-		}
-	} else {
-		ret = ctdb_log_setup_file(mem_ctx, logfile);
-		if (ret != 0) {
-			printf("Setup of file logging failed with \"%s\"\n",
-			       strerror(ret));
-			abort();
+	ctdb_log_init_file();
+	ctdb_log_init_syslog();
+
+	for (b = log_state->backends; b != NULL; b = b->next) {
+		size_t l = strlen(b->prefix);
+		/* Exact match with prefix or prefix followed by ':' */
+		if (strncmp(b->prefix, logging, l) == 0 &&
+		    (logging[l] == '\0' || logging[l] == ':')) {
+			ret = b->setup(mem_ctx, logging, "ctdbd");
+			if (ret == 0) {
+				return true;
+			}
+			printf("Log init for \"%s\" failed with \"%s\"\n",
+			       logging, strerror(ret));
+			return false;
 		}
 	}
-	return 0;
+
+	printf("Unable to find log backend for \"%s\"\n", logging);
+	return false;
 }
 
 /* Note that do_debug always uses the global log state. */
diff --git a/ctdb/server/ctdb_logging_file.c b/ctdb/server/ctdb_logging_file.c
index 28b72231d9d..f931b4a8b83 100644
--- a/ctdb/server/ctdb_logging_file.c
+++ b/ctdb/server/ctdb_logging_file.c
@@ -24,6 +24,8 @@
 #include "system/filesys.h"
 #include "lib/util/time_basic.h"
 
+#define CTDB_LOG_FILE_PREFIX "file"
+
 struct file_state {
 	int fd;
 };
@@ -64,9 +66,19 @@ static int file_state_destructor(struct file_state *state)
        return 0;
 }
 
-int ctdb_log_setup_file(TALLOC_CTX *mem_ctx, const char *logfile)
+static int ctdb_log_setup_file(TALLOC_CTX *mem_ctx,
+			       const char *logging,
+			       const char *app_name)
 {
 	struct file_state *state;
+	const char *logfile;
+	size_t l;
+
+	l = strlen(CTDB_LOG_FILE_PREFIX);
+	if (logging[l] != ':') {
+		return EINVAL;
+	}
+	logfile = &logging[0] + l + 1;
 
 	state = talloc_zero(mem_ctx, struct file_state);
 	if (state == NULL) {
@@ -94,3 +106,8 @@ int ctdb_log_setup_file(TALLOC_CTX *mem_ctx, const char *logfile)
 
 	return 0;
 }
+
+void ctdb_log_init_file(void)
+{
+	ctdb_log_register_backend(CTDB_LOG_FILE_PREFIX, ctdb_log_setup_file);
+}
diff --git a/ctdb/server/ctdb_logging_syslog.c b/ctdb/server/ctdb_logging_syslog.c
index 382c7916e5a..58093375f2d 100644
--- a/ctdb/server/ctdb_logging_syslog.c
+++ b/ctdb/server/ctdb_logging_syslog.c
@@ -54,8 +54,15 @@ static void ctdb_log_to_syslog(void *private_ptr, int dbglevel, const char *s)
 	       "%s%s", debug_extra, s);
 }
 
-int ctdb_log_setup_syslog(void)
+static int ctdb_log_setup_syslog(TALLOC_CTX *mem_ctx,
+				 const char *logging,
+				 const char *app_name)
 {
 	debug_set_callback(NULL, ctdb_log_to_syslog);
 	return 0;
 }
+
+void ctdb_log_init_syslog(void)
+{
+	ctdb_log_register_backend("syslog", ctdb_log_setup_syslog);
+}
diff --git a/ctdb/server/ctdbd.c b/ctdb/server/ctdbd.c
index 16a647ac48c..ec285c043cc 100644
--- a/ctdb/server/ctdbd.c
+++ b/ctdb/server/ctdbd.c
@@ -33,7 +33,7 @@ static struct {
 	const char *public_address_list;
 	const char *event_script_dir;
 	const char *notification_script;
-	const char *logfile;
+	const char *logging;
 	const char *recovery_lock_file;
 	const char *db_dir;
 	const char *db_dir_persistent;
@@ -42,7 +42,6 @@ static struct {
 	const char *single_public_ip;
 	int         valgrinding;
 	int         nosetsched;
-	int         use_syslog;
 	int         start_as_disabled;
 	int         start_as_stopped;
 	int         no_lmaster;
@@ -56,7 +55,7 @@ static struct {
 	.public_address_list = NULL,
 	.transport = "tcp",
 	.event_script_dir = NULL,
-	.logfile = LOGDIR "/log.ctdb",
+	.logging = "file:" LOGDIR "/log.ctdb",
 	.db_dir = CTDB_VARDIR,
 	.db_dir_persistent = CTDB_VARDIR "/persistent",
 	.db_dir_state = CTDB_VARDIR "/state",
@@ -111,7 +110,7 @@ int main(int argc, const char *argv[])
 		{ "public-interface", 0, POPT_ARG_STRING, &options.public_interface, 0, "public interface", "interface"},
 		{ "single-public-ip", 0, POPT_ARG_STRING, &options.single_public_ip, 0, "single public ip", "ip-address"},
 		{ "event-script-dir", 0, POPT_ARG_STRING, &options.event_script_dir, 0, "event script directory", "dirname" },
-		{ "logfile", 0, POPT_ARG_STRING, &options.logfile, 0, "log file location", "filename" },
+		{ "logging", 0, POPT_ARG_STRING, &options.logging, 0, "logging method to be used", NULL },
 		{ "nlist", 0, POPT_ARG_STRING, &options.nlist, 0, "node list file", "filename" },
 		{ "notification-script", 0, POPT_ARG_STRING, &options.notification_script, 0, "notification script", "filename" },
 		{ "listen", 0, POPT_ARG_STRING, &options.myaddress, 0, "address to listen on", "address" },
@@ -123,7 +122,6 @@ int main(int argc, const char *argv[])
 		{ "pidfile", 0, POPT_ARG_STRING, &ctdbd_pidfile, 0, "location of PID file", "filename" },
 		{ "valgrinding", 0, POPT_ARG_NONE, &options.valgrinding, 0, "disable setscheduler SCHED_FIFO call, use mmap for tdbs", NULL },
 		{ "nosetsched", 0, POPT_ARG_NONE, &options.nosetsched, 0, "disable setscheduler SCHED_FIFO call, use mmap for tdbs", NULL },
-		{ "syslog", 0, POPT_ARG_NONE, &options.use_syslog, 0, "log messages to syslog", NULL },
 		{ "start-as-disabled", 0, POPT_ARG_NONE, &options.start_as_disabled, 0, "Node starts in disabled state", NULL },
 		{ "start-as-stopped", 0, POPT_ARG_NONE, &options.start_as_stopped, 0, "Node starts in stopped state", NULL },
 		{ "no-lmaster", 0, POPT_ARG_NONE, &options.no_lmaster, 0, "disable lmaster role on this node", NULL },
@@ -175,10 +173,7 @@ int main(int argc, const char *argv[])
 
 	script_log_level = options.script_log_level;
 
-	ret = ctdb_set_logfile(ctdb, options.logfile, options.use_syslog);
-	if (ret == -1) {
-		printf("ctdb_set_logfile to %s failed - %s\n", 
-		       options.use_syslog?"syslog":options.logfile, ctdb_errstr(ctdb));
+	if (!ctdb_logging_init(ctdb, options.logging)) {
 		exit(1);
 	}