SystemQuery: start filling out fetch_table properly, but it's still unfinished

...hey, at least we know what we're doing nwo and have a plan!

src/lib/SystemQuery.mjs

@@ -5,6 +5,9 @@ import { once, EventEmitter } from 'events';
 import Agent from './agent/Agent.mjs';
 import InfoBroker from './core/InfoBroker.mjs';
 
+import ItemQueue from './async/ItemQueue.mjs';
+
+
 class SystemQuery extends EventEmitter {
 	constructor(config, mode = "agent") {
 		super();
@@ -32,15 +35,15 @@ class SystemQuery extends EventEmitter {
 	
 	async handle_query(peer, msg) {
 		// 1: Validate input
-		if(typeof msg.table !== "string"
-			|| !this.info.is_valid_table(msg.table)) return;
+		if(typeof msg.name !== "string"
+			|| !this.info.is_valid_table(msg.name)) return;
 		
 		// 2: Fetch system info
-		let table = await this.info.fetch_table(msg.table);
+		let table = await this.info.fetch_table(msg.name);
 		if(table === null) return;
 		
 		// 3: Return to requester
-		await peer.send("query-response", { result: table });
+		await peer.send("query-response", { name: msg.name, table });
 	}
 	async handle_query_response(peer, msg) {
 		
@@ -54,22 +57,43 @@ class SystemQuery extends EventEmitter {
 		// If it isn't valid for us, it ain't gonna be valid for anyone else....
 		if(!this.info.is_valid_table(name)) return null;
 		
-		const queue = new p_queue({ })
-		const peers_seen = [];
-		while(peers_seen.length < this.agent.connected_peers.length) {
-			
-		}
+		const queue = new ItemQueue();
 		
 		const handle_response = (peer, msg) => {
 			// TODO: Validate response. Is it the right table? Is it even a table? Note that multiple fetch_table calls may be running in parallel, so we should not make too much of a fuss if we get the wrong table by accident.
 			// TODO: It would be seriously cool to have fetch_table() be an async generator that yields pairs of peer ids and tables as they come in.
-			if(no_peers_left_or_hit_timeout) {
-				this.off("message-query-response", handle_response);
-			}
+			if(typeof msg !== "object"
+				|| typeof msg.table !== "object"
+				|| typeof msg.name !== "string") {
+					l.debug(`Discarding invalid table from peer ${peer.id_short}`);
+					return;
+				}
+			
+			// If it's not the right table, ignore it
+			if(msg.name !== name) return;
+			
+			
+			
+			queue.push({ peer, table: msg.table });
 		};
 		
 		this.on("message-query-response", handle_response);
 		
+		// Only *after* we have our listeners in place do we then broadcast the
+		// query. Note that despite not having entered the below while loop yet,
+		// we do not drop any messages due to the use of the ItemQueue.
+		this.agent.broadcast(`query`, { name });
+		
+		while(peers_seen.length < this.agent.connected_peers.length) {
+			let next = queue.pop(this.config.net.table_config);
+			if(typeof next === "undefined") // We timed out
+				break;
+			
+			yield next;
+		}
+		
+		this.off("message-query-response", handle_response);
+		
 		// FUTURE: Add a cache here? Note that we also do not listen for query responses unless we've asked for a table.
 	}
 }

src/lib/async/ItemQueue.mjs

@@ -13,6 +13,7 @@ class ItemQueue extends EventEmitter {
 	
 	constructor() {
 		super();
+		
 		this.items = [];
 	}
 	

src/subcommands/agent/config.default.toml

@@ -20,3 +20,7 @@ port = 5252
 # The number of retries when connecting to peers.
 # Exponential backoff on retries is enforced
 peer_retries = 5
+
+# Wait this number of seconds before giving up on receiving a table from peers.
+# Decimal values are allowed, and will be rounded to the nearest millisecond.
+table_timeout = 5