From 0d636dabc99276c37d9980ab6458e0f632278a71 Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 13:29:53 +0100
Subject: [PATCH 1/8] Check signature for history keeper in a different process

---
 lib/check-signature.js | 40 ++++++++++++++++++++++++++++++
 lib/commands/core.js   |  1 +
 lib/hk-util.js         | 55 +++++++++++++++++++++++++++++++-----------
 3 files changed, 82 insertions(+), 14 deletions(-)
 create mode 100644 lib/check-signature.js

diff --git a/lib/check-signature.js b/lib/check-signature.js
new file mode 100644
index 000000000..c81ffbb2d
--- /dev/null
+++ b/lib/check-signature.js
@@ -0,0 +1,40 @@
+const Nacl = require('tweetnacl/nacl-fast');
+
+// TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
+
+process.on('message', function (data) {
+    console.log(+new Date(), "Message received by subprocess");
+    if (!data || !data.key || !data.msg || !data.txid) {
+        process.send({
+            error:'E_INVAL'
+        });
+        return;
+    }
+    const txid = data.txid;
+
+    const signedMsg = Nacl.util.decodeBase64(data.msg);
+    var validateKey;
+    try {
+        validateKey = Nacl.util.decodeBase64(data.key);
+    } catch (e) {
+        process.send({
+            txid: txid,
+            error:'E_BADKEY'
+        });
+        return;
+    }
+    // validate the message
+    const validated = Nacl.sign.open(signedMsg, validateKey);
+    if (!validated) {
+        process.send({
+            txid: txid,
+            error:'FAILED'
+        });
+        return;
+    }
+    console.log(+new Date(), "Verification done in the subprocess");
+    process.send({
+        txid: txid,
+        success: true
+    });
+});
diff --git a/lib/commands/core.js b/lib/commands/core.js
index d7add69b4..bb5156749 100644
--- a/lib/commands/core.js
+++ b/lib/commands/core.js
@@ -3,6 +3,7 @@
 const Core = module.exports;
 const Util = require("../common-util");
 const escapeKeyCharacters = Util.escapeKeyCharacters;
+const { fork } = require('child_process');
 
 /*  Use Nacl for checking signatures of messages */
 const Nacl = require("tweetnacl/nacl-fast");
diff --git a/lib/hk-util.js b/lib/hk-util.js
index cb9e9b8ef..6f8c1811a 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -6,6 +6,7 @@ const nThen = require('nthen');
 const Util = require("./common-util");
 const MetaRPC = require("./commands/metadata");
 const Nacl = require('tweetnacl/nacl-fast');
+const { fork } = require('child_process');
 
 const now = function () { return (new Date()).getTime(); };
 const ONE_DAY = 1000 * 60 * 60 * 24; // one day in milliseconds
@@ -921,7 +922,14 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * adds timestamps to incoming messages
     * writes messages to the store
 */
+const check = fork('lib/check-signature.js');
+const onChecked = Util.mkEvent();
+check.on('message', function (res) {
+    onChecked.fire(res);
+});
+
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
+    console.log(+new Date(), "onChannelMessage");
     const Log = Env.Log;
 
     // TODO our usage of 'channel' here looks prone to errors
@@ -962,20 +970,37 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         let signedMsg = (isCp) ? msgStruct[4].replace(CHECKPOINT_PATTERN, '') : msgStruct[4];
         // convert the message from a base64 string into a Uint8Array
 
-        // FIXME this can fail and the client won't notice
-        signedMsg = Nacl.util.decodeBase64(signedMsg);
-
-        // FIXME this can blow up
-        // TODO check that that won't cause any problems other than not being able to append...
-        const validateKey = Nacl.util.decodeBase64(metadata.validateKey);
-        // validate the message
-        const validated = Nacl.sign.open(signedMsg, validateKey);
-        if (!validated) {
-            // don't go any further if the message fails validation
-            w.abort();
-            Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
-            return;
-        }
+        const txid = Util.uid();
+        const next = w();
+
+        // Listen for messages
+        const onCheck = function (res) {
+            if (!res) { return; }
+            if (res.txid !== txid) { return; }
+            // Wev'e received an answer, remove this handler
+            console.log(+new Date(), "Received verification response");
+            onChecked.unreg(onCheck);
+            if (res.error) {
+                // don't go any further if the message fails validation
+                if (res.error === 'FAILED') {
+                    // Signature doesn't match the public key
+                    Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
+                }
+                w.abort();
+                return;
+            }
+            // Success, continue to next block
+            next();
+        };
+        onChecked.reg(onCheck);
+
+        console.log(+new Date(), "Send verification request");
+        // Send the request
+        check.send({
+            txid: txid,
+            msg: signedMsg,
+            key: metadata.validateKey
+        });
     }).nThen(function () {
         // do checkpoint stuff...
 
@@ -1002,7 +1027,9 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         msgStruct.push(now());
 
         // storeMessage
+        console.log(+new Date(), "Storing message");
         storeMessage(Env, channel, JSON.stringify(msgStruct), isCp, getHash(msgStruct[4], Log));
+        console.log(+new Date(), "Message stored");
     });
 };
 

From fb0eb1b20cfbd229c0fbd82c831dce7bd50366d5 Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 14:18:41 +0100
Subject: [PATCH 2/8] Use more subprocesses

---
 lib/check-signature.js |  5 +++++
 lib/hk-util.js         | 33 ++++++++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/lib/check-signature.js b/lib/check-signature.js
index c81ffbb2d..8f3d5edad 100644
--- a/lib/check-signature.js
+++ b/lib/check-signature.js
@@ -1,8 +1,13 @@
 const Nacl = require('tweetnacl/nacl-fast');
 
+// XXX npm "os" and "child_process"
+
 // TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
 
+console.log('New child process', process.pid);
+
 process.on('message', function (data) {
+    console.log('In process', process.pid)
     console.log(+new Date(), "Message received by subprocess");
     if (!data || !data.key || !data.msg || !data.txid) {
         process.send({
diff --git a/lib/hk-util.js b/lib/hk-util.js
index 6f8c1811a..889d5d0b0 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -7,6 +7,7 @@ const Util = require("./common-util");
 const MetaRPC = require("./commands/metadata");
 const Nacl = require('tweetnacl/nacl-fast');
 const { fork } = require('child_process');
+const numCPUs = require('os').cpus().length;
 
 const now = function () { return (new Date()).getTime(); };
 const ONE_DAY = 1000 * 60 * 60 * 24; // one day in milliseconds
@@ -922,11 +923,32 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * adds timestamps to incoming messages
     * writes messages to the store
 */
-const check = fork('lib/check-signature.js');
+
+
 const onChecked = Util.mkEvent();
-check.on('message', function (res) {
-    onChecked.fire(res);
-});
+// Create our workers
+const workers = [];
+for (let i = 0; i < numCPUs; i++) {
+    workers.push(fork('lib/check-signature.js'));
+}
+var initWorker = function (worker) {
+    worker.on('message', function (res) {
+        onChecked.fire(res);
+    });
+    // Spawn a new process in one ends
+    worker.on('exit', function () {
+        // XXX make sure it's dead?
+        var idx = workers.indexOf(worker);
+        if (idx !== -1) {
+            workers.splice(idx, 1);
+        }
+        // Spawn a new one
+        var w = fork('lib/check-signature.js');
+        workers.push(w);
+        initWorker(w);
+    });
+};
+workers.forEach(initWorker);
 
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
     console.log(+new Date(), "onChannelMessage");
@@ -996,7 +1018,8 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         console.log(+new Date(), "Send verification request");
         // Send the request
-        check.send({
+        const random = Math.floor(Math.random() * 4);
+        workers[random].send({
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey

From 923616aef05114c7b24cfdeaf01b25566617eddf Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 15:10:23 +0100
Subject: [PATCH 3/8] Use each process in order instead of using a random one

---
 lib/hk-util.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/hk-util.js b/lib/hk-util.js
index 889d5d0b0..a9b9f0eb1 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -931,6 +931,7 @@ const workers = [];
 for (let i = 0; i < numCPUs; i++) {
     workers.push(fork('lib/check-signature.js'));
 }
+var nextWorker = 0;
 var initWorker = function (worker) {
     worker.on('message', function (res) {
         onChecked.fire(res);
@@ -1018,12 +1019,12 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         console.log(+new Date(), "Send verification request");
         // Send the request
-        const random = Math.floor(Math.random() * 4);
-        workers[random].send({
+        workers[nextWorker].send({
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey
         });
+        if (++nextWorker > numCPUs) { nextWorker = 0; }
     }).nThen(function () {
         // do checkpoint stuff...
 

From 631ea54b49f0f9accb4967135f3d0ec1fb7167c8 Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Tue, 17 Mar 2020 15:40:06 -0400
Subject: [PATCH 4/8] lint compliance

---
 lib/check-signature.js | 4 +++-
 lib/commands/core.js   | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/check-signature.js b/lib/check-signature.js
index 8f3d5edad..6ffd6329e 100644
--- a/lib/check-signature.js
+++ b/lib/check-signature.js
@@ -1,3 +1,5 @@
+/* jshint esversion: 6 */
+/* global process */
 const Nacl = require('tweetnacl/nacl-fast');
 
 // XXX npm "os" and "child_process"
@@ -7,7 +9,7 @@ const Nacl = require('tweetnacl/nacl-fast');
 console.log('New child process', process.pid);
 
 process.on('message', function (data) {
-    console.log('In process', process.pid)
+    console.log('In process', process.pid);
     console.log(+new Date(), "Message received by subprocess");
     if (!data || !data.key || !data.msg || !data.txid) {
         process.send({
diff --git a/lib/commands/core.js b/lib/commands/core.js
index bb5156749..030aaf4ca 100644
--- a/lib/commands/core.js
+++ b/lib/commands/core.js
@@ -3,7 +3,7 @@
 const Core = module.exports;
 const Util = require("../common-util");
 const escapeKeyCharacters = Util.escapeKeyCharacters;
-const { fork } = require('child_process');
+//const { fork } = require('child_process');
 
 /*  Use Nacl for checking signatures of messages */
 const Nacl = require("tweetnacl/nacl-fast");

From 9e85a1411e8507b99e8dc7593bfc8acba39ced62 Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Tue, 17 Mar 2020 16:06:01 -0400
Subject: [PATCH 5/8] abstract the logic around worker choice out of message
 handling

---
 lib/hk-util.js | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/hk-util.js b/lib/hk-util.js
index a9b9f0eb1..b3f917693 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -926,6 +926,7 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
 
 
 const onChecked = Util.mkEvent();
+
 // Create our workers
 const workers = [];
 for (let i = 0; i < numCPUs; i++) {
@@ -951,6 +952,12 @@ var initWorker = function (worker) {
 };
 workers.forEach(initWorker);
 
+const validateMessage = function (msg) {
+    nextWorker = (nextWorker + 1) % workers.length;
+    // Send the request
+    workers[nextWorker].send(msg);
+};
+
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
     console.log(+new Date(), "onChannelMessage");
     const Log = Env.Log;
@@ -1018,13 +1025,11 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         onChecked.reg(onCheck);
 
         console.log(+new Date(), "Send verification request");
-        // Send the request
-        workers[nextWorker].send({
+        validateMessage( {
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey
         });
-        if (++nextWorker > numCPUs) { nextWorker = 0; }
     }).nThen(function () {
         // do checkpoint stuff...
 

From 5467e1ffacd9cf4b982ffc57e1be971a12c6e31f Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Tue, 17 Mar 2020 16:52:41 -0400
Subject: [PATCH 6/8] replace ad-hoc response handler with Util.response

---
 lib/check-signature.js | 26 ++++++++-------
 lib/hk-util.js         | 73 +++++++++++++++++++++++-------------------
 2 files changed, 55 insertions(+), 44 deletions(-)

diff --git a/lib/check-signature.js b/lib/check-signature.js
index 6ffd6329e..5e6682a73 100644
--- a/lib/check-signature.js
+++ b/lib/check-signature.js
@@ -9,39 +9,43 @@ const Nacl = require('tweetnacl/nacl-fast');
 console.log('New child process', process.pid);
 
 process.on('message', function (data) {
-    console.log('In process', process.pid);
-    console.log(+new Date(), "Message received by subprocess");
+    //console.log('In process', process.pid);
+    //console.log(+new Date(), "Message received by subprocess");
     if (!data || !data.key || !data.msg || !data.txid) {
-        process.send({
+        return void process.send({
             error:'E_INVAL'
         });
-        return;
     }
     const txid = data.txid;
 
-    const signedMsg = Nacl.util.decodeBase64(data.msg);
+    var signedMsg;
+    try {
+        signedMsg = Nacl.util.decodeBase64(data.msg);
+    } catch (e) {
+        return void process.send({
+            txid: txid,
+            error: 'E_BAD_MESSAGE',
+        });
+    }
+
     var validateKey;
     try {
         validateKey = Nacl.util.decodeBase64(data.key);
     } catch (e) {
-        process.send({
+        return void process.send({
             txid: txid,
             error:'E_BADKEY'
         });
-        return;
     }
     // validate the message
     const validated = Nacl.sign.open(signedMsg, validateKey);
     if (!validated) {
-        process.send({
+        return void process.send({
             txid: txid,
             error:'FAILED'
         });
-        return;
     }
-    console.log(+new Date(), "Verification done in the subprocess");
     process.send({
         txid: txid,
-        success: true
     });
 });
diff --git a/lib/hk-util.js b/lib/hk-util.js
index b3f917693..c669254ad 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -925,17 +925,20 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
 */
 
 
-const onChecked = Util.mkEvent();
-
 // Create our workers
 const workers = [];
 for (let i = 0; i < numCPUs; i++) {
     workers.push(fork('lib/check-signature.js'));
 }
 var nextWorker = 0;
+
+const response = Util.response();
+
 var initWorker = function (worker) {
     worker.on('message', function (res) {
-        onChecked.fire(res);
+        if (!res || !res.txid) { return; }
+        //console.log(+new Date(), "Received verification response");
+        response.handle(res.txid, [res.error]);
     });
     // Spawn a new process in one ends
     worker.on('exit', function () {
@@ -952,14 +955,32 @@ var initWorker = function (worker) {
 };
 workers.forEach(initWorker);
 
-const validateMessage = function (msg) {
+
+const validateMessage = function (signedMsg, key, _cb) {
+    // let's be paranoid about asynchrony and only calling back once..
+    var cb = Util.once(Util.mkAsync(_cb));
+
+    var txid = Util.uid();
+
+    // expect a response within 15s
+    response.expect(txid, cb, 15000);
+
     nextWorker = (nextWorker + 1) % workers.length;
+    if (workers.length === 0 || typeof(workers[nextWorker].send) !== 'function') {
+        console.error(workers);
+        throw new Error("INVALID_WORKERS");
+    }
+
     // Send the request
-    workers[nextWorker].send(msg);
+    workers[nextWorker].send({
+        txid: txid,
+        msg: signedMsg,
+        key: key,
+    });
 };
 
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
-    console.log(+new Date(), "onChannelMessage");
+    //console.log(+new Date(), "onChannelMessage");
     const Log = Env.Log;
 
     // TODO our usage of 'channel' here looks prone to errors
@@ -1000,36 +1021,22 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         let signedMsg = (isCp) ? msgStruct[4].replace(CHECKPOINT_PATTERN, '') : msgStruct[4];
         // convert the message from a base64 string into a Uint8Array
 
-        const txid = Util.uid();
-        const next = w();
+        //const txid = Util.uid();
 
         // Listen for messages
-        const onCheck = function (res) {
-            if (!res) { return; }
-            if (res.txid !== txid) { return; }
-            // Wev'e received an answer, remove this handler
-            console.log(+new Date(), "Received verification response");
-            onChecked.unreg(onCheck);
-            if (res.error) {
-                // don't go any further if the message fails validation
-                if (res.error === 'FAILED') {
-                    // Signature doesn't match the public key
+        //console.log(+new Date(), "Send verification request");
+        validateMessage(signedMsg, metadata.validateKey, w(function (err) {
+            if (err) {
+                // validation can fail in multiple ways
+                if (err === 'FAILED') {
+                    // we log this case, but not others for some reason
                     Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
                 }
-                w.abort();
-                return;
+                // always abort if there was an error...
+                return void w.abort();
             }
-            // Success, continue to next block
-            next();
-        };
-        onChecked.reg(onCheck);
-
-        console.log(+new Date(), "Send verification request");
-        validateMessage( {
-            txid: txid,
-            msg: signedMsg,
-            key: metadata.validateKey
-        });
+            // otherwise it was successful!
+        }));
     }).nThen(function () {
         // do checkpoint stuff...
 
@@ -1056,9 +1063,9 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         msgStruct.push(now());
 
         // storeMessage
-        console.log(+new Date(), "Storing message");
+        //console.log(+new Date(), "Storing message");
         storeMessage(Env, channel, JSON.stringify(msgStruct), isCp, getHash(msgStruct[4], Log));
-        console.log(+new Date(), "Message stored");
+        //console.log(+new Date(), "Message stored");
     });
 };
 

From 019e5e708bb7f631a2b71e1245b40a2eb9145e8b Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Tue, 17 Mar 2020 17:23:35 -0400
Subject: [PATCH 7/8] wrap workers in a function scope and add a
 validateMessage method to HK's Env

---
 lib/check-signature.js |  4 +-
 lib/historyKeeper.js   |  2 +
 lib/hk-util.js         | 96 ++++++++++++++++++++++--------------------
 3 files changed, 53 insertions(+), 49 deletions(-)

diff --git a/lib/check-signature.js b/lib/check-signature.js
index 5e6682a73..26839ccee 100644
--- a/lib/check-signature.js
+++ b/lib/check-signature.js
@@ -5,9 +5,7 @@ const Nacl = require('tweetnacl/nacl-fast');
 // XXX npm "os" and "child_process"
 
 // TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
-
-console.log('New child process', process.pid);
-
+//console.log('New child process', process.pid);
 process.on('message', function (data) {
     //console.log('In process', process.pid);
     //console.log(+new Date(), "Message received by subprocess");
diff --git a/lib/historyKeeper.js b/lib/historyKeeper.js
index fcd291414..a3a33c4e6 100644
--- a/lib/historyKeeper.js
+++ b/lib/historyKeeper.js
@@ -76,6 +76,8 @@ module.exports.create = function (config, cb) {
         domain: config.domain
     };
 
+    HK.initializeValidationWorkers(Env);
+
     (function () {
         var pes = config.premiumUploadSize;
         if (!isNaN(pes) && pes >= Env.maxUploadSize) {
diff --git a/lib/hk-util.js b/lib/hk-util.js
index c669254ad..915d5772e 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -924,59 +924,63 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * writes messages to the store
 */
 
+HK.initializeValidationWorkers = function (Env) {
+    if (typeof(Env.validateMessage) !== 'undefined') {
+        return void console.error("validation workers are already initialized");
+    }
 
-// Create our workers
-const workers = [];
-for (let i = 0; i < numCPUs; i++) {
-    workers.push(fork('lib/check-signature.js'));
-}
-var nextWorker = 0;
-
-const response = Util.response();
+    // Create our workers
+    const workers = [];
+    for (let i = 0; i < numCPUs; i++) {
+        workers.push(fork('lib/check-signature.js'));
+    }
 
-var initWorker = function (worker) {
-    worker.on('message', function (res) {
-        if (!res || !res.txid) { return; }
-        //console.log(+new Date(), "Received verification response");
-        response.handle(res.txid, [res.error]);
-    });
-    // Spawn a new process in one ends
-    worker.on('exit', function () {
-        // XXX make sure it's dead?
-        var idx = workers.indexOf(worker);
-        if (idx !== -1) {
-            workers.splice(idx, 1);
-        }
-        // Spawn a new one
-        var w = fork('lib/check-signature.js');
-        workers.push(w);
-        initWorker(w);
-    });
-};
-workers.forEach(initWorker);
+    const response = Util.response();
 
+    var initWorker = function (worker) {
+        worker.on('message', function (res) {
+            if (!res || !res.txid) { return; }
+            //console.log(+new Date(), "Received verification response");
+            response.handle(res.txid, [res.error]);
+        });
+        // Spawn a new process in one ends
+        worker.on('exit', function () {
+            // XXX make sure it's dead?
+            var idx = workers.indexOf(worker);
+            if (idx !== -1) {
+                workers.splice(idx, 1);
+            }
+            // Spawn a new one
+            var w = fork('lib/check-signature.js');
+            workers.push(w);
+            initWorker(w);
+        });
+    };
+    workers.forEach(initWorker);
 
-const validateMessage = function (signedMsg, key, _cb) {
-    // let's be paranoid about asynchrony and only calling back once..
-    var cb = Util.once(Util.mkAsync(_cb));
+    var nextWorker = 0;
+    Env.validateMessage = function (signedMsg, key, _cb) {
+        // let's be paranoid about asynchrony and only calling back once..
+        var cb = Util.once(Util.mkAsync(_cb));
 
-    var txid = Util.uid();
+        var txid = Util.uid();
 
-    // expect a response within 15s
-    response.expect(txid, cb, 15000);
+        // expect a response within 15s
+        response.expect(txid, cb, 15000);
 
-    nextWorker = (nextWorker + 1) % workers.length;
-    if (workers.length === 0 || typeof(workers[nextWorker].send) !== 'function') {
-        console.error(workers);
-        throw new Error("INVALID_WORKERS");
-    }
+        nextWorker = (nextWorker + 1) % workers.length;
+        if (workers.length === 0 || typeof(workers[nextWorker].send) !== 'function') {
+            console.error(workers);
+            throw new Error("INVALID_WORKERS");
+        }
 
-    // Send the request
-    workers[nextWorker].send({
-        txid: txid,
-        msg: signedMsg,
-        key: key,
-    });
+        // Send the request
+        workers[nextWorker].send({
+            txid: txid,
+            msg: signedMsg,
+            key: key,
+        });
+    };
 };
 
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
@@ -1025,7 +1029,7 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         // Listen for messages
         //console.log(+new Date(), "Send verification request");
-        validateMessage(signedMsg, metadata.validateKey, w(function (err) {
+        Env.validateMessage(signedMsg, metadata.validateKey, w(function (err) {
             if (err) {
                 // validation can fail in multiple ways
                 if (err === 'FAILED') {

From f8ad649b4524d4b7b42f263c607c2389807503e2 Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Wed, 18 Mar 2020 10:30:42 -0400
Subject: [PATCH 8/8] [style] bail out early to avoid nesting

---
 lib/hk-util.js | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/lib/hk-util.js b/lib/hk-util.js
index 915d5772e..2bcae56e3 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -1030,16 +1030,15 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         // Listen for messages
         //console.log(+new Date(), "Send verification request");
         Env.validateMessage(signedMsg, metadata.validateKey, w(function (err) {
-            if (err) {
-                // validation can fail in multiple ways
-                if (err === 'FAILED') {
-                    // we log this case, but not others for some reason
-                    Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
-                }
-                // always abort if there was an error...
-                return void w.abort();
+            // no errors means success
+            if (!err) { return; }
+            // validation can fail in multiple ways
+            if (err === 'FAILED') {
+                // we log this case, but not others for some reason
+                Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
             }
-            // otherwise it was successful!
+            // always abort if there was an error...
+            return void w.abort();
         }));
     }).nThen(function () {
         // do checkpoint stuff...