hot-shots - npm Package Compare versions

Comparing version 8.1.0 to 8.2.0

CHANGES.md

 CHANGELOG
 =========
 
+## 8.2.0 (2020-9-30)
+* @dhermes Making UDS error handling and recovery more robust. Note these look to be ok in a minor release but are signficant upgrades to how UDS works. Thanks as well to @prognant for an overlapping PR.
+
 ## 8.1.0 (2020-9-25)
@@ -5,0 +8,0 @@ * @maleblond Support multiple values for the same tag key

lib/constants.js

@@ -0,1 +1,4 @@
+const os = require('os'),
+  process = require('process');
+
 exports.PROTOCOL = {
@@ -7,1 +10,27 @@ TCP: 'tcp',
 };
+
+/**
+ * Determines error codes that signify a connection to a Unix Domain Socket (UDS)
+ * has failed in a way that can be retried. This codes are OS-specific.
+ * @returns {number[]} An array of the error codes.
+ */
+function udsErrors() {
+  if (process.platform === 'linux') {
+    return [
+      os.constants.errno.ENOTCONN,
+      os.constants.errno.ECONNREFUSED,
+    ];
+  }
+
+  if (process.platform === 'darwin') {
+    return [
+      os.constants.errno.EDESTADDRREQ,
+      os.constants.errno.ECONNRESET,
+    ];
+  }
+
+  // Unknown / not yet implemented
+  return [];
+}
+
+exports.udsErrors = udsErrors;

lib/statsd.js

@@ -1,8 +0,11 @@
-const util = require('util'),
+const process = require('process'),
+  util = require('util'),
   helpers = require('./helpers'),
   applyStatsFns = require('./statsFunctions');
 
-const { PROTOCOL } = require('./constants');
+const constants = require('./constants');
 const createTransport = require('./transport');
 
+const PROTOCOL = constants.PROTOCOL;
+const UDS_ERROR_CODES = constants.udsErrors();
 const UDS_DEFAULT_GRACEFUL_RESTART_LIMIT = 1000;
@@ -51,2 +54,4 @@ const CACHE_DNS_TTL_DEFAULT = 60000;
   this.port = options.port || parseInt(process.env.DD_DOGSTATSD_PORT, 10) || 8125;
+  this.path = options.path;
+  this.stream = options.stream;
   this.prefix = options.prefix || '';
@@ -72,2 +77,4 @@ this.suffix = options.suffix || '';
   this.udsGracefulErrorHandling = 'udsGracefulErrorHandling' in options ? options.udsGracefulErrorHandling : true;
+  this.udsGracefulRestartRateLimit = options.udsGracefulRestartRateLimit || UDS_DEFAULT_GRACEFUL_RESTART_LIMIT; // only recreate once per second
+  this.isChild = options.isChild;
 
@@ -99,12 +106,4 @@ // If we're mocking the client, create a buffer to record the outgoing calls.
 
-  if (! this.socket) {
-    this.socket = createTransport(this, {
-      host: this.host,
-      cacheDns: this.cacheDns,
-      cacheDnsTtl: this.cacheDnsTtl,
-      path: options.path,
-      port: this.port,
-      protocol: this.protocol,
-      stream: options.stream
-    });
+  if (!this.socket) {
+    trySetNewSocket(this);
   }
@@ -125,39 +124,7 @@
   // does not support options.isChild (how to re-create a socket you didn't create?)
-  if (this.socket && !options.isChild && options.protocol === PROTOCOL.UDS && this.udsGracefulErrorHandling) {
-    const socketCreateLimit = options.udsGracefulRestartRateLimit || UDS_DEFAULT_GRACEFUL_RESTART_LIMIT; // only recreate once per second
+  if (this.socket && options.protocol === PROTOCOL.UDS) {
     const lastSocketCreateTime = Date.now();
-    this.socket.on('error', (err) => {
-      const code = err.code;
-      switch (code) {
-        case 107:
-        case 111: {
-          if (Date.now() - lastSocketCreateTime >= socketCreateLimit) {
-            // recreate the socket, but only once per 30 seconds
-            if (this.errorHandler) {
-              this.socket.removeListener('error', this.errorHandler);
-            }
-            this.socket.close();
-            this.socket = createTransport(this, {
-              host: this.host,
-              path: options.path,
-              port: this.port,
-              protocol: this.protocol
-            });
-
-            if (this.errorHandler) {
-              this.socket.on('error', this.errorHandler);
-            } else {
-              this.socket.on('error', error => console.error(`hot-shots UDS error: ${error}`));
-            }
-          }
-          break;
-        }
-        default: {
-          break;
-        }
-      }
-    });
+    maybeAddUDSErrorHandler(this, lastSocketCreateTime);
   }
 
-
   this.messagesInFlight = 0;
@@ -361,3 +328,12 @@ this.CHECKS = {
 
-  if (!this.socket) {
+  const socketWasMissing = !this.socket;
+  if (socketWasMissing && this.protocol === PROTOCOL.UDS) {
+    trySetNewSocket(this);
+    if (this.socket) {
+      // On success, add custom UDS error handling.
+      maybeAddUDSErrorHandler(this, Date.now());
+    }
+  }
+
+  if (socketWasMissing) {
     const error = new Error('Socket not created properly. Check previous errors for details.');
@@ -534,1 +510,83 @@ if (callback) {
 exports.StatsD = Client;
+
+/**
+ * Handle an error connecting to a Unix Domain Socket (UDS). This will
+ * attempt to create a new socket and replace and close the client's current
+ * socket, registering a **new** `udsErrorHandler()` on the newly created socket.
+ * If a new socket can't be created (e.g. if no UDS currently exists at
+ * `client.path`) then this will leave the existing socket intact.
+ *
+ * Note that this will no-op with an early exit if the last socket create time
+ * was too recent (within the UDS graceful restart rate limit).
+ * @param client Client The statsd Client that may be getting a UDS error handler.
+ * @param lastSocketCreateTime number The timestamp (in milliseconds since the
+ *        epoch) when the current socket was created.
+ */
+function udsErrorHandler(client, lastSocketCreateTime) {
+  // recreate the socket, but only once within `udsGracefulRestartRateLimit`.
+  if (Date.now() - lastSocketCreateTime < client.udsGracefulRestartRateLimit) {
+    return;
+  }
+
+  if (client.errorHandler) {
+    client.socket.removeListener('error', client.errorHandler);
+  }
+
+  const newSocket = createTransport(client, {
+    host: client.host,
+    path: client.path,
+    port: client.port,
+    protocol: client.protocol,
+  });
+  if (newSocket) {
+    client.socket.close();
+    client.socket = newSocket;
+    maybeAddUDSErrorHandler(client, Date.now());
+  } else {
+    console.error('Could not replace UDS connection with new socket');
+    return;
+  }
+
+  if (client.errorHandler) {
+    client.socket.on('error', client.errorHandler);
+  } else {
+    client.socket.on('error', (error) => console.error(`hot-shots UDS error: ${error}`));
+  }
+}
+
+/**
+ * Add a Unix Domain Socket (UDS) error handler to the client's socket, if the
+ * client is not a "child" client and has graceful error handling enabled for
+ * UDS.
+ * @param client Client The statsd Client that may be getting a UDS error handler.
+ * @param lastSocketCreateTime number The timestamp (in milliseconds since the
+ *        epoch) when the current socket was created.
+ */
+function maybeAddUDSErrorHandler(client, lastSocketCreateTime) {
+  if (client.isChild || !client.udsGracefulErrorHandling) {
+    return;
+  }
+
+  client.socket.on('error', (err) => {
+    if (UDS_ERROR_CODES.includes(-err.code)) {
+      udsErrorHandler(client, lastSocketCreateTime);
+    }
+  });
+}
+
+/**
+ * Try to replace a client's socket with a new transport. If `createTransport()`
+ * returns `null` this will still set the client's socket to `null`.
+ * @param client Client The statsd Client that will be getting a new socket
+ */
+function trySetNewSocket(client) {
+  client.socket = createTransport(client, {
+    host: client.host,
+    cacheDns: client.cacheDns,
+    cacheDnsTtl: client.cacheDnsTtl,
+    path: client.path,
+    port: client.port,
+    protocol: client.protocol,
+    stream: client.stream,
+  });
+}

package.json

 {
   "name": "hot-shots",
   "description": "Node.js client for StatsD, DogStatsD, and Telegraf",
-  "version": "8.1.0",
+  "version": "8.2.0",
   "author": "Steve Ivy",
@@ -6,0 +6,0 @@ "types": "./types.d.ts",

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Improved metrics

Total package byte prevSize

83561

increased by3.77%

Lines of code

1541

increased by5.19%

No dependency changes