cloud_discovery: add blacklist for discovery methods

Introduce a blacklist mechanism to avoid retrying failed discovery
methods within the same discovery cycle. Each time a method fails
validation, it is added to the blacklist. The blacklist is cleared
once the device transitions to ONLINE or after all discovery methods
have been attempted.

This prevents repeated attempts of failing methods and ensures the
discovery process progresses more reliably.

Signed-off-by: Marek Kwaczynski <marek@shasta.cloud>

feeds/tip/cloud_discovery/files/usr/bin/cloud_discovery

@@ -23,6 +23,7 @@ let ubus = libubus.connect();
 let uci = libuci.cursor();
 let state = DISCOVER;
 let discovery_method = "";
+let discovery_block_list = [];
 let validate_time;
 let offline_time;
 let orphan_time;
@@ -102,6 +103,9 @@ function gateway_load() {
 }
 
 function discovery_state_write() {
+	if (length(discovery_method) == 0)
+		return;
+
 	let discovery_state = {
 		"type": discovery_method,
 		"updated": time()
@@ -155,6 +159,7 @@ function set_state(set) {
 		ulog(LOG_INFO, 'Wait for validation\n');
 		validate_time = time();
 		state = VALIDATING;
+		push(discovery_block_list, discovery_method);
 		break;
 
 	case ONLINE:
@@ -163,6 +168,7 @@ function set_state(set) {
 			ulog(LOG_INFO, 'Setting cloud controller to validated\n');
 			gateway_write({ valid: true });
 			discovery_state_write();
+			discovery_block_list = [];
 		}
 		break;
 
@@ -231,6 +237,13 @@ function time_is_valid() {
 	return valid;
 }
 
+function is_discover_method_blacked() {
+	if (discovery_method in discovery_block_list)
+		return true;
+
+	return false;
+}
+
 function interval_handler() {
 	printf(`State ${state}\n`);
 	switch(state) {
@@ -264,15 +277,17 @@ function interval_handler() {
 			return;
 
 		discovery_method = DISCOVER_DHCP;
-		if (discover_dhcp())
+		if (!is_discover_method_blacked() && discover_dhcp())
 			return;
 
 		discovery_method = DISCOVER_FLASH;
-		if (!discover_flash())
+		if (!is_discover_method_blacked() && !discover_flash())
 			return;
 
 		discovery_method = DISCOVER_LOOKUP;
 		redirector_lookup();
+
+		discovery_block_list = [];
 		break;
 
 	case VALIDATING: