victorquinn / memcache-plus Goto Github PK

Hi,

Could you please implement the additional memcached commands:
add, replace, append, prepend, cas, incr/decr?

thx,

Broken out from #14

Hello,
We have a very busy production application that is attempting to update via memcache-plus (approximately 200-250 updates/second). Periodically, we see the connection drop and fail:
Error [ERR_STREAM_DESTROYED]: Cannot call write after a stream was destroyed at doWrite (_stream_writable.js:406:19) at writeOrBuffer (_stream_writable.js:394:5) at Socket.Writable.write (_stream_writable.js:294:11) at Connection.write (/opt/nisient/lib/node/node_modules/memcache-plus/lib/connection.js:418:21) at Connection.<anonymous> (/opt/nisient/lib/node/node_modules/memcache-plus/lib/connection.js:504:18) at Connection.tryCatcher (/opt/nisient/lib/node/node_modules/bluebird/js/release/util.js:16:23) at Promise._settlePromiseFromHandler (/opt/nisient/lib/node/node_modules/bluebird/js/release/promise.js:547:31) at Promise._settlePromise (/opt/nisient/lib/node/node_modules/bluebird/js/release/promise.js:604:18) at Promise._settlePromiseCtx (/opt/nisient/lib/node/node_modules/bluebird/js/release/promise.js:641:10) at _drainQueueStep (/opt/nisient/lib/node/node_modules/bluebird/js/release/async.js:97:12) at _drainQueue (/opt/nisient/lib/node/node_modules/bluebird/js/release/async.js:86:9) at Async._drainQueues (/opt/nisient/lib/node/node_modules/bluebird/js/release/async.js:102:5) at Immediate.Async.drainQueues [as _onImmediate] (/opt/nisient/lib/node/node_modules/bluebird/js/release/async.js:15:14) at runCallback (timers.js:705:18) at tryOnImmediate (timers.js:676:5) at processImmediate (timers.js:658:5) Error: Memcache connection lost at /opt/nisient/lib/node/node_modules/memcache-plus/lib/connection.js:157:25 at List.__iterate (/opt/nisient/lib/node/node_modules/immutable/dist/immutable.js:2206:13) at List.forEach (/opt/nisient/lib/node/node_modules/immutable/dist/immutable.js:4381:19) at Connection.destroy (/opt/nisient/lib/node/node_modules/memcache-plus/lib/connection.js:156:24) at Timeout._onTimeout (/opt/nisient/lib/node/node_modules/memcache-plus/lib/connection.js:205:30) at ontimeout (timers.js:436:11) at tryOnTimeout (timers.js:300:5) at listOnTimeout (timers.js:263:5) at Timer.processTimers (timers.js:223:10)
without recovery. Currently using 0.2.21 and about to update to 0.2.22, but need some help in diagnosing the problem as it's causing production issues. Thanks so much in advance, we've come to rely upon this module.
Rob

If I cache data that contains a nested Buffer object, such as [Buffer, string], then inside of formatValue() the Buffer.isBuffer(val) check returns false and we fall into the JSON.stringify(val) path:

And this results in a JSON string that, when parsed, produces an object that looks like:

[
  {
    type: "Buffer",
    data: "...",
  },
  string
]

which of course is not the same shape as the [Buffer, string] object that was originally registered, which is I believe a bug.

I'm noticing that this throws an error if I attempt to require it after requiring connect-rest. To reproduce, run this script:

var rest = require('connect-rest');
var memcached_plus = require('memcache-plus');

Here's the error on my machine:

TypeError: Cannot redefine property: find
    at Function.defineProperty (native)
    at define (/Users/kirkcp/Documents/interactives/express/node_modules/memcache-plus/node_modules/collections/shim-array.js:56:12)
    at Object.<anonymous> (/Users/kirkcp/Documents/interactives/express/node_modules/memcache-plus/node_modules/collections/shim-array.js:135:1)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/Users/kirkcp/Documents/interactives/express/node_modules/memcache-plus/node_modules/collections/generic-collection.js:272:1)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)

Hello, found a problem regarding this code:

misc.assert(key.length < 250, 'Key must be less than 250 characters long');

It asserts on character count rather than string byte length. So keys with characters that occupy 2 bytes will be measured incorrectly, leading to a runtime crash.

Steps to reproduce:

var MemcachePlus = require('memcache-plus');

var client = new MemcachePlus();
var key = Array(250).join('Я');

client.set(key, 'test');

Run with:

DEBUG=* node index.js

Output:

  memcache-plus:client Connect options { autodiscover: false,
  bufferBeforeError: 1000,
  disabled: false,
  hosts: null,
  reconnect: true,
  onNetError: [Function: onNetError],
  queue: true,
  netTimeout: 500,
  backoffLimit: 10000,
  maxValueSize: 1048576 } +0ms
  memcache-plus:client starting connection +3ms
  memcache-plus:client connecting to all hosts +0ms
  memcache-plus:connection connecting to host localhost:11211 +1ms
  memcache-plus:connection successfully (re)connected! +8ms
  memcache-plus:client flushing client write buffer +0ms
  memcache-plus:connection trying to flush buffer for localhost +3ms
  memcache-plus:connection sending: "set ЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯЯ..." +1ms
  memcache-plus:connection sending: "test" +0ms
  memcache-plus:connection got data: "CLIENT_ERROR bad command line format" and the queue now has "1" elements +1ms
  memcache-plus:connection responded and the queue now has "0" elements +1ms
  memcache-plus:connection got data: "ERROR" and the queue now has "0" elements +0ms
/home/vitalii/projects/mem-test/node_modules/memcache-plus/lib/connection.js:246
    if (deferred.type === 'autodiscovery') {
                 ^

TypeError: Cannot read property 'type' of undefined
    at Connection.read (/home/vitalii/projects/mem-test/node_modules/memcache-plus/lib/connection.js:246:18)
    at Carrier.emit (events.js:198:13)
    at /home/vitalii/projects/mem-test/node_modules/carrier/lib/carrier.js:24:12
    at process._tickCallback (internal/process/next_tick.js:61:11)

Correct check would be using https://nodejs.org/api/buffer.html#buffer_class_method_buffer_bytelength_string_encoding , i guess

netTimeout is a supported option which allows clients to modify the time that the cache client waits for a response from the cache server through Bluebird's Promise method, .timeout.

Problem is, netTimeout is not correctly getting passed from the Client class instance to each of the Connection instances. This results in netTimeout getting set to the default value of 500ms.

http://blog.elijaa.org/2010/12/24/understanding-memcached-stats-cachedump-command/

Hi,

I'm using this client in a lambda function on Amazon AWS.

I have an ElastiCache Memcached cluster of 2 nodes.
I'm passing these nodes to the connection. (I'm not using the auto discover feature).
The connection, set, get, delete funcionality are working fine.

However the flush functionality is not flushing the data.

memcachePlus = new MemcachePlus( { hosts: memcacheHosts } ); memcachePlus.flush().then(onFlushComplete);

No errors are thrown, but data is still there.

Scenario:
Set a key-value item.
Get by key to make sure it's inserted.
Flush data.
Get by key again which should return null, but instead returns the data.

Hello,
We have been chasing down a very low percentage issue (about 100 out of every 1M writes) where the promise resolves from a set before the contents of the cache have changed. We have validated this by:
result = await memcached.set(cacheKey, m1); let delay = await wait(5); let r1 = await memcached.get(cacheKey);
and comparing m1/r1. In this case, the contents are a deeply nested JSON object (about 4-5 levels deep) of around 30kB. The content is effectively the same for all writes, apart from a few simple value changes. We are using 0.2.21 on node 10.12.0. memcached is 1.4.25 Ubuntu. Any suggestions or help gladly appreciated.

If cached retrieve exists in the tests, I can't find it. There's certainly no documentation for it. How do you do it?

I have got a bluebird warning.

Warning: a promise was created in a handler but was not returned from it is occuring at lib/client.jsL170

Warning: a promise was created in a handler but was not returned from it
https://github.com/petkaantonov/bluebird/blob/master/docs/docs/warning-explanations.md

I added a line to client.js:

this.hosts = hosts;
this.connectToHosts();
this.flushBuffer();
+ return Promise.resolve();

and the warning is disappeared though return Promise.resolve() doesn't look good.

Stack traces are like:

Warning: a promise was created in a handler at anonymous> (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:170:14 but was not returned from it, see http://goo.gl/rRqMUw
    at new Promise (/home/share/shun_tak/project/node_modules/bluebird/js/release/promise.js:77:14)
    at Object.exports.defer (/home/share/shun_tak/project/node_modules/memcache-plus/lib/misc.js:15:19)
    at Connection.get (/home/share/shun_tak/project/node_modules/memcache-plus/lib/connection.js:713:25)
    at Client.flushBuffer (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:219:48)
    at Client.<anonymous> (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:170:14)
From previous event:
    at Client.getHostList (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:167:26)
    at Client.connect (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:79:14)
    at new Client (/home/share/shun_tak/project/node_modules/memcache-plus/lib/client.js:61:10)
    at Object.<anonymous> (/home/share/shun_tak/project/handlers/sample.js:9:19)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at AwsInvokeLocal.invokeLocalNodeJs (/usr/lib/node_modules/serverless/lib/plugins/aws/invokeLocal/index.js:79:16)
    at AwsInvokeLocal.invokeLocal (/usr/lib/node_modules/serverless/lib/plugins/aws/invokeLocal/index.js:61:19)
    at processImmediate [as _immediateCallback] (timers.js:383:17)

I will appreciate your help with this situation.

I've tried this in Node versions 4.6.1, 6.2.0, 6.5.0 and 6.9.0:

new MemcachePlus({hosts: [/* my autodiscover endpoint */], autodiscover: true});

My endpoint is of the format: something.cfg.use1.cache.amazonaws.com, i've tried it with and without adding the port (11211) to the end.

I get this exception:

> TypeError: Cannot read property 'key' of undefined
    at Connection.read (/opt/web/node_modules/memcache-plus/lib/connection.js:262:34)
    at emitOne (events.js:96:13)
    at Carrier.emit (events.js:188:7)
    at /opt/web/node_modules/memcache-plus/node_modules/carrier/lib/carrier.js:24:12
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickDomainCallback (internal/process/next_tick.js:122:9)
> Unhandled rejection RangeError: "port" option should be >= 0 and < 65536: undefined
    at lookupAndConnect (net.js:959:13)
    at Socket.connect (net.js:934:5)
    at Object.exports.connect.exports.createConnection (net.js:74:35)
    at Connection.connect (/opt/web/node_modules/memcache-plus/lib/connection.js:186:27)
    at new Connection (/opt/web/node_modules/memcache-plus/lib/connection.js:136:10)
    at Client.<anonymous> (/opt/web/node_modules/memcache-plus/lib/client.js:186:34)
    at Array.forEach (native)
    at Client.connectToHosts (/opt/web/node_modules/memcache-plus/lib/client.js:181:16)
    at Client.<anonymous> (/opt/web/node_modules/memcache-plus/lib/client.js:169:14)
    at bound (domain.js:280:14)
    at Client.runBound (domain.js:293:12)
    at Client.tryCatcher (/opt/web/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/opt/web/node_modules/bluebird/js/release/promise.js:510:31)
    at Promise._settlePromise (/opt/web/node_modules/bluebird/js/release/promise.js:567:18)
    at Promise._settlePromise0 (/opt/web/node_modules/bluebird/js/release/promise.js:612:10)
    at Promise._settlePromises (/opt/web/node_modules/bluebird/js/release/promise.js:691:18)

• stats
• stats items
• stats slabs
• stats sizes

Broken out from #14

Is there any documentation for the library?

• client.js:8 Object.
  [buharmetre]/[memcache-plus]/lib/client.js:8:14

as chai is used within client.js, it should be instead listed in dependencies in package.json not devDependencies.

For example if you delete node from elastiacache memcached cluster while it's being used,
https://github.com/petergoldstein/dalli automatically failover and send traffics to other nodes, Without re-loading autodiscovery.
In general, When there are multiple nodes and if one of node goes "fail" (disconnected for long while... etc) then mark that node as unavailable and use other nodes.

Do you guys have plan to implement this kind of failover?

Looks that something wrong with cachedump or it's tests.
On my local VM(node v12.20.1, memcached 1.5.6) cachedump test always fails:

1) Client cachedump should work gets cache metadata:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.

Unhandled rejection TypeError: Cannot read property 'key' of undefined
    at /home/roman/memcache-plus/test/client.js:1267:36
    at tryCatcher (/home/roman/memcache-plus/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/home/roman/memcache-plus/node_modules/bluebird/js/release/promise.js:547:31)
    at Promise._settlePromise (/home/roman/memcache-plus/node_modules/bluebird/js/release/promise.js:604:18)
    at Promise._settlePromise0 (/home/roman/memcache-plus/node_modules/bluebird/js/release/promise.js:649:10)
    at Promise._settlePromises (/home/roman/memcache-plus/node_modules/bluebird/js/release/promise.js:729:18)
    at _drainQueueStep (/home/roman/memcache-plus/node_modules/bluebird/js/release/async.js:93:12)
    at _drainQueue (/home/roman/memcache-plus/node_modules/bluebird/js/release/async.js:86:9)
    at Async._drainQueues (/home/roman/memcache-plus/node_modules/bluebird/js/release/async.js:102:5)
    at Immediate.Async.drainQueues [as _onImmediate] (/home/roman/memcache-plus/node_modules/bluebird/js/release/async.js:15:14)
    at processImmediate (internal/timers.js:461:21)

Although memcached doesn't support namespaces or tags natively, it can be built on top of it. They also describe an approach for doing so here.

This would be a great feature addition to memcache-plus without requiring it to be implemented in user land.

Hello,
I was checking out this repo for a job and i found out that backoffLimit is never sended to the Connection constructor, when having one host. It's just a minor fix, so i'll make the PR for that if it's ok.

thanks!

The recent publish is missing the items() and cachedump() fns

I'm trying to check if the memcached server is up before I run my app (using bufferBeforeError). I have the following code:

  static testConnection () {
    return new Promise((resolve, reject) => {
      const mc = new MemcachePlus({
        hosts: ['localhost:11211'],
        bufferBeforeError: 0
      })

      // I also just tried return mc.set(..) without the outer promise
      mc.set('startup', 'true').then(resolve).catch(reject)
    })
  }

But I keep getting the following thrown/rejected:

Error: Connection is not ready, either not connected yet or disconnected
    at Client.run (/Volumes/sixfive-cs/vault/node_modules/memcache-plus/lib/client.js:467:31)
    at Client.set (/Volumes/sixfive-cs/vault/node_modules/memcache-plus/lib/client.js:307:17)
    at /Volumes/sixfive-cs/vault/lib/TempStorage.js:63:10
    at Function.testConnection (/Volumes/sixfive-cs/vault/lib/TempStorage.js:57:12)
    at Object.<anonymous> (/Volumes/sixfive-cs/vault/bin/vault-server.js:12:13)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Module.runMain (module.js:575:10)
    at run (node.js:348:7)
    at startup (node.js:140:9)
    at node.js:463:3

My memcached server is running; when I switch to an older branch of my code using the memcached module, things work

Broken out from #14

  let s1 = await memInst.set(key5, '10abc');
  await memInst.increase(key5);

when key's value is not integer, get the wrong error.
output : Error: Memcache returned an error: %s

Broken out from #14

Hi there,

Is it possible to connect to the memcached configured to work via unix socket?

I can't see any details whether it is possible in docs.
Also tried to specify path to socket in host option like this:

hosts: ['/var/run/memcached/memcached.sock:0']

but got an error:

Error: getaddrinfo ENOTFOUND /var/run/memcached/memcached.sock
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:67:26) {
  errno: -3008,
  code: 'ENOTFOUND',
  syscall: 'getaddrinfo',
  hostname: '/var/run/memcached/memcached.sock'
}

While checking the code found out something what I can't understand:

In misc.js we have:

exports.defer = function defer(key) {
    key = key || null;

    var resolve, reject;
    var promise = new Promise(function() {
        resolve = arguments[0];
        reject = arguments[1];
    });
    return {
        key: key,
        resolve: resolve,
        reject: reject,
        promise: promise
    };
};

Then in connection.js in set/cas/add/replace/append/prepend methods there is the following code:

            var deferred = misc.defer(key);
            deferred.key = key;

Looks that we set the same value for key property two times: in defer func and after it return.
Is it really necessary to set key property the same value twice?

Hi All,

any plans to support SASL ? (login/password); I'd need it for using it with https://app.redislabs.com

thanks

const mc = new memcached({hosts: [process.env.memcache], autodiscover: true})

babel src --out-dir bin

src/api.js -> bin/api.js
validating package
TypeError: Cannot read property 'split' of undefined
at Client.splitHost (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/node_modules/memcache-plus/lib/client.js:230:19)
at Client. (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/node_modules/memcache-plus/lib/client.js:153:22)
at Array.map (native)
at Client.getHostList (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/node_modules/memcache-plus/lib/client.js:152:35)
at Client.connect (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/node_modules/memcache-plus/lib/client.js:79:14)
at new Client (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/node_modules/memcache-plus/lib/client.js:61:10)
at Object. (/private/var/folders/w4/0_jcj9dd67g3ycr39nbzp8kh0000gn/T/9b8b4587-e1c6-4219-a679-a574b6c692fc/bin/api.js:68:12)
at Module._compile (module.js:571:32)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
at validatePackage (/Users/m/.npm-packages/lib/node_modules/claudia/src/tasks/validate-package.js:15:15)
at initEnvVarsFromOptions.then.then.then.then.then.then.then.dir (/Users/m/.npm-packages/lib/node_modules/claudia/src/commands/update.js:140:10)

hashring version is not compatible with the latest stable release of Node (4.2.6).

In package.json it needs to be upgrade to ^3.2.0

Broken out from #14

Hello,

Firstly, let me thank you for developing the great plugin.

However, there is a one functionality that I miss in order to use the plugin on Lambda - disconnect(). Unfortunately, AWS Lambdas has to clear all the connections in order to finish execution - this includes memcached connections as well. Currently, the Lambdas are timing out due to connection working in a background.

Would you mind providing such function? Alternatively, I'll try to make a PR for that

Best regards,
Rafal

If you're not with queue enabled, version will mostly fail, because it isn't a promise.

It should be a promise executed after the server connect, because you can't know the version if the server isn't connected.

Append and Prepend commands doesn't change the expire from the item (TTL), so you need either give support to touch or add the TTL support by doing the touch with the new TTL if the value isn't 0.

More info at: https://blog.elijaa.org/2010/05/21/memcached-telnet-command-summary/#append

please, either:

• update chai.js dep to current version so that we can use your lib with use strict mode, or
• get rid of the chai.js dep (which is a heavy/large lib not meant to be used in production, IMHO) in your lib completely and re-impl the few assert checks on your own (preferred)

Does this library support memcache touch method?

Hi!

I want to provide some functionality to my application while using memcache-plus library.

I'm currently using the library as part of my project, also I've MemCachier (heroku add-on) as my cache's server. The thing is that I need to authenticate to the server and I did something like proposed here: https://www.memcachier.com/documentation/supported-protocols-ascii-binary. Basically, I'm setting a cache item right after the connection attempt with key=username and value=password so it can establish connection. The issue that I have been experiencing is how to deal with reconnection if the server has any failure, is there a way to set a callback function when trying to reconnect? I need to set that username/password item again in order to avoid connection failure.

I will really appreciate any help that you can provide, by the way great work with the library!

Thank you

Hi,
I've pushed a pull request some time ago. I wonder if this project is being maintained, if not, I need to push this to NPM as a new project, that I would definitely try to avoid.
Thank you!

Hi, I'm trying to build a Memcached desktop, and I need to fetch all the keys stored in Memcached.

Because Memcached's cachedump command can only dump the COLD item, so I need to use the lru_crawler metadump command to fetch all keys. See this link

I trying to add such method by myself.
First, I add a keys method in client.js

Client.prototype.keys = function(cb) {
    return this.run('lru_crawler metadump all', [], cb);
};

Second, I try to add lru_crawler metadump all method for Connection in connection.js

Connection.prototype['lru_crawler metadump all'] = function() {
 // How to implement ? 
};

Now, how to deal with the response data in lru_crawler metadump all is complicated for me, so can you add such method or tell me how to implement ?
Thanks.

I'm a develop from China, so please forgive me English :)

Please add this check to
function validateKey(key, operation) {
misc.assert(key, 'Cannot "' + operation + '" without key!');
misc.assert(typeof key === 'string', 'Key needs to be of type "string"');
misc.assert(key.length < 250, 'Key must be less than 250 characters long');
}

Memcached does not allow spaces in the key...
https://stackoverflow.com/questions/5826768/can-memcached-keys-contain-spaces

I'm trying to port my memcached code over to memcached-plus, and it does not seem that the commands reject when there are server issues, and instead onNetError seems to be the catch-all.

The problem I'm having is that the memcached library commands can return an error in the callback, which I generally use as part of my promise rejection.

However, with memcached-plus, the lib call just hangs there, as if waiting to resolve indefinitely if I shut down the memcached server mid-transaction. My fear is that if the server is down, these promises will continue to queue up with heavy usage.

Ideally I'd like the error to be a rejection on the promise. Is that possible to do?

Here's what I'm trying to do:

  function failure (reject, err) {
    // do some error handling then have a custom error be caught downstream
   // *including server net issues*

   ...
    reject(getResponseObj(DB_FAILURE))
  }
...

 // assume this is a method in my memcache client
  del (key) {
    return new Promise ((resolve, reject) => {
      this.memcached.delete(key).then(resolve).catch((err) => failure(reject, err))
    })
  }

Here
https://github.com/victorquinn/memcache-plus/blob/master/lib/connection.js#L247

deferred is undefined when the list is empty, thus resulting in an undefined error

It crashes with the stack trace as below:

node_modules/memcache-plus/lib/connection.js:246
    if (deferred.type === 'autodiscovery') {
                 ^

TypeError: Cannot read property 'type' of undefined
    at Connection.read (node_modules/memcache-plus/lib/connection.js:246:18)
    at Carrier.emit (events.js:315:20)
    at Carrier.EventEmitter.emit (domain.js:486:12)
    at node_modules/carrier/lib/carrier.js:24:12
    at processTicksAndRejections (internal/process/task_queues.js:75:11)

I'm running a benchmark script which calls many get/set/append/remove commands.
It works in most cases, and crashes in other cases at the same environment.

• node v14.15.1
• memcached (server) 1.5.22
• memcache-plus (client) 0.2.21

It's usually a devDep and it's a bit odd to see it installed as part of a production install. I can understand maybe if you're going to run tests before prod is started, but if you're going to do that, you'd probably have the lib at the application level, not at this module level.

See this for more details on current implementation.

Turns out, we can use the Memcached flags in order to implement the "what gets put in gets pulled out" functionality. This may not be entirely compatible with another library as they could use the flags for something different, but it seems this is the most ideal solution.

I will evaluate other libraries and see if there is some consensus as to the value of these flags to indicate type.

This is not entirely a prerequisite for implementing incr/decr but generally needed and a good idea.

When I set something into memcache where the value is a multi-lined string (delimiter of \n), when I get the value back, it contains only the last line.