reorg
This commit is contained in:
Raven Scott
@@ -0,0 +1,216 @@
|
||||
const dgram = require('dgram');
|
||||
const dnsPacket = require('dns-packet');
|
||||
const { logDebug, logError, logWarn, logInfo } = require('../infrastructure/logger');
|
||||
|
||||
// DNS resolver connection pool
|
||||
class DNSPool {
|
||||
constructor(maxConnections = 5) {
|
||||
this.maxConnections = maxConnections;
|
||||
this.resolvers = [];
|
||||
this.activeQueries = new Map();
|
||||
this.queryId = 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Get or create a DNS resolver socket
|
||||
* @returns {dgram.Socket} - DNS resolver socket
|
||||
*/
|
||||
getResolver() {
|
||||
if (this.resolvers.length < this.maxConnections) {
|
||||
const resolver = dgram.createSocket('udp4');
|
||||
resolver.on('error', (err) => {
|
||||
logError('DNSPool', `Resolver error: ${err.message}`);
|
||||
});
|
||||
this.resolvers.push(resolver);
|
||||
return resolver;
|
||||
}
|
||||
// Round-robin through existing resolvers
|
||||
return this.resolvers[this.queryId % this.resolvers.length];
|
||||
}
|
||||
|
||||
/**
|
||||
* Get list of DNS servers from environment variable
|
||||
* @returns {string[]} - Array of DNS server IP addresses
|
||||
*/
|
||||
getDnsServers() {
|
||||
const publicDnsServerEnv = process.env.PUBLIC_DNS_SERVER || '1.1.1.1';
|
||||
return publicDnsServerEnv.split(',').map(s => s.trim()).filter(s => s.length > 0);
|
||||
}
|
||||
|
||||
/**
|
||||
* Query public DNS with failover support
|
||||
* @param {object} query - DNS query object
|
||||
* @returns {Promise<object|null>} - DNS response or null
|
||||
*/
|
||||
async query(query) {
|
||||
const dnsServers = this.getDnsServers();
|
||||
|
||||
// Try each DNS server in order (failover strategy)
|
||||
for (let serverIndex = 0; serverIndex < dnsServers.length; serverIndex++) {
|
||||
const publicDNSServer = dnsServers[serverIndex];
|
||||
const isLastServer = serverIndex === dnsServers.length - 1;
|
||||
|
||||
const result = await new Promise((resolve) => {
|
||||
const resolver = this.getResolver();
|
||||
const queryId = ++this.queryId;
|
||||
let resolved = false;
|
||||
|
||||
const cleanup = () => {
|
||||
if (!resolved) {
|
||||
resolved = true;
|
||||
const queryData = this.activeQueries.get(queryId);
|
||||
if (queryData) {
|
||||
// Remove listeners explicitly
|
||||
if (queryData.handler) {
|
||||
resolver.removeListener('message', queryData.handler);
|
||||
}
|
||||
if (queryData.errorHandler) {
|
||||
resolver.removeListener('error', queryData.errorHandler);
|
||||
}
|
||||
if (queryData.timeout) {
|
||||
clearTimeout(queryData.timeout);
|
||||
}
|
||||
this.activeQueries.delete(queryId);
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
// Set timeout
|
||||
const timeout = setTimeout(() => {
|
||||
logWarn('DNSPool', `DNS query timeout for ${query.questions[0].name} on server ${publicDNSServer}`);
|
||||
cleanup();
|
||||
resolve(null);
|
||||
}, 5000);
|
||||
|
||||
const handler = (msg) => {
|
||||
if (resolved) return;
|
||||
clearTimeout(timeout);
|
||||
try {
|
||||
const response = dnsPacket.decode(msg);
|
||||
logDebug('DNSPool', `Public DNS response for ${query.questions[0].name} from ${publicDNSServer}: ${JSON.stringify(response.answers)}`);
|
||||
cleanup();
|
||||
resolve(response);
|
||||
} catch (err) {
|
||||
logError('DNSPool', `Error decoding DNS response from ${publicDNSServer}: ${err.message}`);
|
||||
cleanup();
|
||||
resolve(null);
|
||||
}
|
||||
};
|
||||
|
||||
const errorHandler = (err) => {
|
||||
if (resolved) return;
|
||||
clearTimeout(timeout);
|
||||
logWarn('DNSPool', `Error receiving DNS response from ${publicDNSServer}: ${err.message}`);
|
||||
cleanup();
|
||||
resolve(null);
|
||||
};
|
||||
|
||||
// Store query data with resolver reference for proper cleanup
|
||||
this.activeQueries.set(queryId, { handler, errorHandler, timeout, resolver });
|
||||
resolver.once('message', handler);
|
||||
resolver.once('error', errorHandler);
|
||||
|
||||
const encodedQuery = dnsPacket.encode(query);
|
||||
resolver.send(encodedQuery, 53, publicDNSServer, (err) => {
|
||||
if (err) {
|
||||
clearTimeout(timeout);
|
||||
logWarn('DNSPool', `Error forwarding DNS query to ${publicDNSServer}: ${err.message}`);
|
||||
resolver.removeListener('message', handler);
|
||||
resolver.removeListener('error', errorHandler);
|
||||
cleanup();
|
||||
resolve(null);
|
||||
}
|
||||
});
|
||||
});
|
||||
|
||||
// If we got a successful response, return it
|
||||
if (result) {
|
||||
return result;
|
||||
}
|
||||
|
||||
// If this was the last server, return null
|
||||
if (isLastServer) {
|
||||
logWarn('DNSPool', `All DNS servers failed for ${query.questions[0].name}`);
|
||||
return null;
|
||||
}
|
||||
|
||||
// Otherwise, try next server
|
||||
logDebug('DNSPool', `DNS server ${publicDNSServer} failed, trying next server...`);
|
||||
}
|
||||
|
||||
return null;
|
||||
}
|
||||
|
||||
/**
|
||||
* Close all resolvers
|
||||
*/
|
||||
close() {
|
||||
// Clean up all active queries and their listeners
|
||||
for (const [queryId, query] of this.activeQueries.entries()) {
|
||||
if (query.timeout) {
|
||||
clearTimeout(query.timeout);
|
||||
}
|
||||
// Remove listeners from resolver
|
||||
if (query.resolver && query.handler) {
|
||||
try {
|
||||
query.resolver.removeListener('message', query.handler);
|
||||
} catch (err) {
|
||||
logDebug('DNSPool', `Error removing message listener: ${err.message}`);
|
||||
}
|
||||
}
|
||||
if (query.resolver && query.errorHandler) {
|
||||
try {
|
||||
query.resolver.removeListener('error', query.errorHandler);
|
||||
} catch (err) {
|
||||
logDebug('DNSPool', `Error removing error listener: ${err.message}`);
|
||||
}
|
||||
}
|
||||
}
|
||||
this.activeQueries.clear();
|
||||
|
||||
// Close all resolvers and remove all listeners
|
||||
for (const resolver of this.resolvers) {
|
||||
try {
|
||||
// Remove all listeners to prevent leaks
|
||||
resolver.removeAllListeners();
|
||||
resolver.close();
|
||||
} catch (err) {
|
||||
logError('DNSPool', `Error closing resolver: ${err.message}`);
|
||||
}
|
||||
}
|
||||
this.resolvers = [];
|
||||
}
|
||||
}
|
||||
|
||||
// Global DNS pool instance
|
||||
const dnsPool = new DNSPool(parseInt(process.env.DNS_POOL_SIZE || '5', 10));
|
||||
|
||||
/**
|
||||
* Update DNS pool configuration at runtime
|
||||
* @param {number} maxConnections - New maximum number of connections
|
||||
*/
|
||||
function updateDnsPool(maxConnections) {
|
||||
const oldMax = dnsPool.maxConnections;
|
||||
dnsPool.maxConnections = maxConnections;
|
||||
|
||||
// If reducing pool size, close excess resolvers
|
||||
if (maxConnections < oldMax && dnsPool.resolvers.length > maxConnections) {
|
||||
const excessResolvers = dnsPool.resolvers.splice(maxConnections);
|
||||
for (const resolver of excessResolvers) {
|
||||
try {
|
||||
resolver.removeAllListeners();
|
||||
resolver.close();
|
||||
} catch (err) {
|
||||
logError('DNSPool', `Error closing excess resolver: ${err.message}`);
|
||||
}
|
||||
}
|
||||
logInfo('DNSPool', `Reduced pool size from ${oldMax} to ${maxConnections}, closed ${excessResolvers.length} resolvers`);
|
||||
} else if (maxConnections > oldMax) {
|
||||
logInfo('DNSPool', `Increased pool size from ${oldMax} to ${maxConnections}, new resolvers will be created on demand`);
|
||||
}
|
||||
|
||||
// PUBLIC_DNS_SERVER is already read from process.env at query time, so no action needed
|
||||
}
|
||||
|
||||
module.exports = { dnsPool, DNSPool, updateDnsPool };
|
||||
|
||||
Reference in New Issue
Block a user