Error: Future resolved more than once

[cope]

So, I get a "User successfully retrieved from LDAP server", but then right after the below error :(

I am using:

LDAP.generateSettings = function (request) {
    return {
        "serverDn": "DC=mycompany,DC=com",
        "serverUrl": "ldap://111.111.111.11",
        "whiteListedFields": ["displayName", "mail", "memberOf"],
        "autopublishFields": ["displayName", "mail", "memberOf"]
    };
}

And this is the error:

I20150826-13:45:12.114(2)? User successfully retrieved from LDAP server
W20150826-13:45:12.164(2)? (STDERR)
W20150826-13:45:12.165(2)? (STDERR) C:\Users\cope\AppData\Local\.meteor\packages\meteor-tool\1.1.4\mt-os.win_32\dev_bundle\server-lib\node_modules\fibers\future.js:226
W20150826-13:45:12.165(2)? (STDERR)                     throw new Error('Future resolved more than once');
W20150826-13:45:12.165(2)? (STDERR)                           ^
W20150826-13:45:12.165(2)? (STDERR) Error: Future resolved more than once
W20150826-13:45:12.165(2)? (STDERR)     at Object.Future.return (C:\Users\cope\AppData\Local\.meteor\package-tool\1.1.4\mt-os.windows.x86_32\dev_bundle\server-lib\node_modules\fibers\future.js:226:10)
W20150826-13:45:12.165(2)? (STDERR)     at EventEmitter.<anonymous> (packages/babrahams:accounts-ldap/ldap_serve:1)
W20150826-13:45:12.165(2)? (STDERR)     at EventEmitter.emit (events.js:95:17)
W20150826-13:45:12.166(2)? (STDERR)     at _done (C:\Users\cope\AppData\Local\.meteor\packages\babrahams_accap\0.3.1\npm\node_modules\ldapjs\lib\client\client.js:785:22)
W20150826-13:45:12.166(2)? (STDERR)     at messageCallback (C:\Users\cope\AppData\Local\.meteor\packages\babccounts-ldap\0.3.1\npm\node_modules\ldapjs\lib\client\client.js:858:14)
W20150826-13:45:12.166(2)? (STDERR)     at Parser.onMessage (C:\Users\cope\AppData\Local\.meteor\packages\baaccounts-ldap\0.3.1\npm\node_modules\ldapjs\lib\client\client.js:199:12)
W20150826-13:45:12.166(2)? (STDERR)     at Parser.emit (events.js:95:17)
W20150826-13:45:12.166(2)? (STDERR)     at Parser.write (C:\Users\cope\AppData\Local\.meteor\packages\babrahunts-ldap\0.3.1\npm\node_modules\ldapjs\lib\messages\parser.js:105:8)
W20150826-13:45:12.166(2)? (STDERR)     at end (C:\Users\cope\AppData\Local\.meteor\packages\babrahams_accou\0.3.1\npm\node_modules\ldapjs\lib\messages\parser.js:71:19)
W20150826-13:45:12.167(2)? (STDERR)     at Parser.write (C:\Users\cope\AppData\Local\.meteor\packages\babrahunts-ldap\0.3.1\npm\node_modules\ldapjs\lib\messages\parser.js:107:10)
=> Exited with code: 8

[JackAdams]

This was an issue previously (#3), and I thought I'd fixed it, but apparently not.
:( indeed.

[cope]

Let me know if there is anything I can do to help... I am using 0.3.1:

babrahams:accounts-ldap        added, version 0.3.1
babrahams:accounts-ldap-ionic  added, version 0.1.8
sacha:spin                     added, version 2.3.1

[JackAdams]

I had a quick look through the code and couldn't spot how any of the Futures could be resolving twice, but I have to admit - I'm pretty shaky when it comes to Fibers and Futures.

If you'd like to take a look at the code in this part of the codebase, that's probably where the error is occurring.

[cope]

I am a total n00b when it comes to Futures :( Never used it so far.

Do you need a for loop on line 115? What if you just have:

//for (var k in serverDNs) {
    var serverDn = serverDNs[0].split(/,?DC=/).slice(1).join('.');

    ...

    success = bindFuture.wait();
    // if (success) { break; }
//}

?

[JackAdams]

Yeah, that's there so you can put an array in as the value for serverDn. For the settings you're generating, that for loop is only going to run once, so it wouldn't make any difference.

[cope]

I thought so too...

Question, is client.bind asynchronous?

[JackAdams]

Yep. client.bind is async. So is client.search. That's why there's a need for Futures.

[cope]

And then here then

success = bindFuture.wait();

the code waits for the asynchronous call to return the value?

Then I am almost 100% sure that the problem is NOT in _bind.

Which would mean it is below in _search where searchFuture is used?

Is it possible for the client.search call to fire two events? Maybe "searchEntry" and "searchReference" events? OR, and this seems more likely to me, "error" and "end" events one after another? Or the "end" event after any other event?

[cope]

WAIT! Notice above, I get: "User successfully retrieved from LDAP server", which means we are looking in the wrong place, aren't we? Line 299:

LDAP.log("User successfully retrieved from LDAP server");

which is well after _bind and _search finished, right?

[JackAdams]

Okay. I'm glad you persisted with this. I'm also pretty sure that _bind is not the problem and that, like you say, there is a possibility that the _search Future resolves twice - once on something (not sure which yet) and then again on end. The first resolution lets the rest of the code run, so the function returns and the code down around line 299 runs. Then, on end, it tries to resolve again, finds that that ship has already sailed, and throws an error.

My guess is that an empty userObj is being "successfully" retrieved from the LDAP server on searchEntry, which causes searchFuture to return, and then on end, we find userObj is empty and searchFuture returns again with false (so now it has resolved twice, leading to the error).

I have a rough and ready fix sketched out in my head, but I don't think I'll have time to test and release a new version today.

[cope]

OK, so bad news, my error log in the OP was somehow cut-off at the worse line, the good news is that I have the new log and it shows exactly where the problem is!

W20150826-15:39:25.549(2)? (STDERR) Error: Future resolved more than once
W20150826-15:39:25.549(2)? (STDERR)     at Object.Future.return (C:\Users\cope\AppData\Local\.meteor\packages\meteor-tool\1.1.4\mt-os.windows.x86_32\dev_bundle\server-lib\node_modules\fibers\future.js:226:10)
W20150826-15:39:25.549(2)? (STDERR)     at EventEmitter.<anonymous> (packages/babrahams:accounts-ldap/ldap_server.js:180:1)

As you can see, the line is 180, which is:

searchFuture.return(false);

under searchReference event:

res.on('searchReference', function (referral) {
    LDAP.log('referral: ' + referral.uris.join());
    searchFuture.return(false);
});

[cope]

Today is NOT an issue :) No worries, I can live without it :D

I just started with Meteor like a week ago, and I wanted to build an app to convince my boss that Meteor is the way to go from now on :D And for that I needed an LDAP login...

The good news is that my boss is on vacation for another 10 days, so I have time :D

[JackAdams]

Ah ... then my guess above was wrong, but this is very helpful info!
I'll try to release a new version in the next day or two with a fix, but I'll need a bit of time to replicate the error in a dev environment first.

[cope]

Whenever you release it, I'll be here to test it :)

Thanks!

[JackAdams]

Cool. Thanks for your help with this. Very much appreciated.

[cope]

Just thinking out loud here, and I appologize if this is a dumb question...

but, is there such a thing as future.unwait or unbind, or something that will tell the future object it should not listen anymore?

[JackAdams]

I'd have to read up on the docs about Futures. I think I should do that anyway ... 😁

Sent from my iPhone

On Aug 27, 2015, at 4:36 PM, Predrag Stojadinovic [email protected] wrote:

Just thinking out loud here, and I appologize if this is a dumb question...

but, is there such a thing as future.unwait or unbind, or something that will tell the future object it should not listen anymore?

—
Reply to this email directly or view it on GitHub.

[cope]

:D Can you live a link to those docs here as well, googling with the word "future" just gives back stupid results :(

[JackAdams]

https://github.com/laverdet/node-fibers

Just noticed that there is an isResolved() API call. That should solve all our problems. I'll try to release a new version in the next hour or two.

[JackAdams]

Okay. Just released 0.3.2. Will be interested to hear what happens.

[cope]

So, it seems that the Future issue is resolved. After "User successfully retrieved from LDAP server" it prints a whole bunch of text starting with {"dn":"CN=...

But then throws this error:

I20150827-13:59:59.635(2)? Exception while invoking method 'login' TypeError: Cannot read property '' of null
I20150827-13:59:59.635(2)?     at [object Object].Package (packages/babrahams:accounts-ldap/ldap_server.js:320:1)
I20150827-13:59:59.635(2)?     at packages/accounts-base/accounts_server.js:358:1
I20150827-13:59:59.635(2)?     at tryLoginMethod (packages/accounts-base/accounts_server.js:161:1)
I20150827-13:59:59.636(2)?     at runLoginHandlers (packages/accounts-base/accounts_server.js:355:1)
I20150827-13:59:59.636(2)?     at [object Object].Meteor.methods.login (packages/accounts-base/accounts_server.js:409:1)

I20150827-13:59:59.636(2)?     at maybeAuditArgumentChecks (packages/ddp/livedata_server.js:1617:1)
I20150827-13:59:59.636(2)?     at packages/ddp/livedata_server.js:648:1
I20150827-13:59:59.640(2)?     at [object Object]._.extend.withValue (packages/meteor/dynamics_nodejs.js:56:1)
I20150827-13:59:59.640(2)?     at packages/ddp/livedata_server.js:647:1
I20150827-13:59:59.640(2)?     at [object Object]._.extend.withValue (packages/meteor/dynamics_nodejs.js:56:1)
I20150827-13:59:59.640(2)? referral: ldap://DomainDnsZones.mycompany.com/DC=DomainDnsZones,DC=mycompany,DC=com
I20150827-13:59:59.640(2)? referral: ldap://ForestDnsZones.mycompany.com/DC=ForestDnsZones,DC=mycompany,DC=com
I20150827-13:59:59.641(2)? referral: ldap://nvprod.mycompany.com/DC=nvprod,DC=mycompany,DC=com
I20150827-13:59:59.641(2)? referral: ldap://mycompany.com/CN=Configuration,DC=mycompany,DC=com
I20150827-13:59:59.641(2)? status: 0

It says ldap_server.js:320 but that line is commented out?

[JackAdams]

You're getting a referral there. This is something the package won't help with. I don't think it's going to be able to retrieve a record from your LDAP server unless you change the settings you're using.

I've just released 0.3.3 which doesn't throw an error in this situation, but still doesn't solve your problem.

[cope]

Crap :( I have no idea where the referral comes from :(

I am using these settings:

LDAP.generateSettings = function (request) {
    return {
        "serverDn": "DC=mycompany,DC=com",
        "serverUrl": "ldap://111.11.111.11",
        "whiteListedFields": ["displayName", "userprincipalname", "mail", "memberOf"],
        "autopublishFields": ["displayName", "userprincipalname", "mail", "memberOf"]
    };
}

[cope]

Question, given that this happens:

"User successfully retrieved from LDAP server"

is it possible to, well, stop there?

What I mean is, the user and pwd are confirmed, so what could be causing those referrals? :(

[JackAdams]

Does the latest version (0.3.3) still say

"User successfully retrieved from LDAP server"

and then fail?

[cope]

I'll have to recheck on Monday at work, but looking at the comments above, I did update after you announced 0.3.3, so I would say yes.

[JackAdams]

Weird. And the data that immediately follows User successfully retrieved from LDAP server looks like a correct record from the LDAP server, complete with username and email fields?

[cope]

Exactly. (again, I will recheck on Monday to confirm this properly)

[JackAdams]

Hmm... I'm running out of ideas.

If you want to play around with this a bit, to see if you can isolate exactly what's going on, you could clone this repo into a /packages directory in the root directory of your app and then that local version will override my version from atmosphere until you delete the cloned-and-modified package from the /packages directory. That will allow you to make changes, test and troubleshoot locally. And if you find a solution I'll be more than happy to merge the changes back into master. In fact, I'll be really, really grateful. But no pressure -- it's just a way you can take the situation into your own hands if you want to. :-)

[cope]

Not a bad idea. I will try that first thing on Monday, then.

[cope]

Sorry for not replying yesterday, bugs happened, must be taken care of... Hopefully I will have some time during the week to try your suggestion.

[JackAdams]

No problem at all. If you can figure it out, that'd be fantastic but, like I said, no pressure from my side -- I see any contributions as an unexpected bonus. You've already done a lot to tighten up the existing codebase by keeping this issue alive and giving feedback on the latest releases.

[JackAdams]

Sorry for being so quiet on this issue for so long. I've released 0.4.6 today, which may or may not help. In any case, I'm grateful for your encouragement in debugging this package.

[skarborg]

This was happening to me when my filter was too "wide" (objectClass=user) resulting in many matches and callbacks from ldapjs client. With a proper search filter (&(CN=username)(objectClass=user)) and one match/result this stopped happening.

[skarborg]

Shouldnt the

searchFuture.return

in

.on('searchEntry'

also be wrapped with

if (!searchFuture.isResolved()) {
}

?

Thanks for great package btw

[JackAdams]

Well... that explains a few things. And, yes, it should be wrapped as you've suggested. I imagine that would have prevented the future from resolving more than once when the net was cast too wide and it returned multiple matches.

The thanks really belong to someone else. I just took hive:accounts-ldap and kept modifying it in response to my app's needs. I don't actually know a heck of a lot about futures, LDAP, etc.

[catonice]

Good day peeps,
I encountered this error "Future resolve more than once" and tried a lot of things to fix it.
I found that some specific serverDns would cause this error to be thrown and this comment by @skarborg gave me that clue to selectively test each one (I can run against multiple serverDns but in my specific case a few were the culprits):
"This was happening to me when my filter was too "wide" (objectClass=user) resulting in many matches and callbacks from ldapjs client. With a proper search filter (&(CN=username)(objectClass=user)) and one match/result this stopped happening."
I removed the problem dns in my case (I don't have a lot of knowledge on what dns we are using so).
I hope this helps someone else.
Thanks!