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!
This commit is contained in:
Starbeamrainbowlabs 2022-02-09 03:06:52 +00:00
parent b1485d5410
commit a736acc1b7
Signed by: sbrl
GPG key ID: 1BE5172E637709C2
3 changed files with 41 additions and 12 deletions

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@ -5,6 +5,9 @@ import { once, EventEmitter } from 'events';
import Agent from './agent/Agent.mjs'; import Agent from './agent/Agent.mjs';
import InfoBroker from './core/InfoBroker.mjs'; import InfoBroker from './core/InfoBroker.mjs';
import ItemQueue from './async/ItemQueue.mjs';
class SystemQuery extends EventEmitter { class SystemQuery extends EventEmitter {
constructor(config, mode = "agent") { constructor(config, mode = "agent") {
super(); super();
@ -32,15 +35,15 @@ class SystemQuery extends EventEmitter {
async handle_query(peer, msg) { async handle_query(peer, msg) {
// 1: Validate input // 1: Validate input
if(typeof msg.table !== "string" if(typeof msg.name !== "string"
|| !this.info.is_valid_table(msg.table)) return; || !this.info.is_valid_table(msg.name)) return;
// 2: Fetch system info // 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; if(table === null) return;
// 3: Return to requester // 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) { 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 it isn't valid for us, it ain't gonna be valid for anyone else....
if(!this.info.is_valid_table(name)) return null; if(!this.info.is_valid_table(name)) return null;
const queue = new p_queue({ }) const queue = new ItemQueue();
const peers_seen = [];
while(peers_seen.length < this.agent.connected_peers.length) {
}
const handle_response = (peer, msg) => { 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: 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. // 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) { if(typeof msg !== "object"
this.off("message-query-response", handle_response); || 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); 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. // FUTURE: Add a cache here? Note that we also do not listen for query responses unless we've asked for a table.
} }
} }

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

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@ -20,3 +20,7 @@ port = 5252
# The number of retries when connecting to peers. # The number of retries when connecting to peers.
# Exponential backoff on retries is enforced # Exponential backoff on retries is enforced
peer_retries = 5 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