# Issue with 3rd-party memc and eval modules

**URL:** <https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545>\
**Category:** NGINX\
**Created:** [February 16, 2010, 11:53am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545 "2010-02-16T11:53:31Z")\
**Posts on this page:** 18\
**Page:** 1

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 16, 2010, 11:53am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/1 "2010-02-16T11:53:31Z")

</div>

Hi,

There is an issue with the 3rd-party memc module for Nginx [1](http://wiki.nginx.org/NginxHttpMemcModule) where it  
doesn’t close the connection when it resides in an eval [2](http://www.grid.net.ru/nginx/eval.en.html) block.

Consider the following with memc in eval:

```
   eval $memc_return
   {
     set $memc_cmd 'set';
     set $memc_key 'key';
     set $memc_value 'value';

     memc_pass memcache_cluster;
   }

  echo 'hello!';
  echo_flush;

```

When this location is called via curl, you’ll get to see the following:

- About to connect() to localhost port 81 (#0)
- Trying 127.0.0.1… connected
- Connected to localhost (127.0.0.1) port 81 (#0)

> GET  
> /session/synchronize/da39a3ee5e6b4b0d3255bfef95601890afd80709/da39a3ee5e6b4b0d3255bfef95601890afd80709/abc  
> HTTP/1.1  
> User-Agent: curl/7.19.5 (i486-pc-linux-gnu) libcurl/7.19.5 OpenSSL/0.9.8g  
> zlib/1.2.3.3 libidn/1.15  
> Host: localhost:81  
> Accept: _/_

^C  
markus@zealand:/opt/nginx#

You can see i have to close the connection manually. I have also got a  
verbose  
memcache server log which exactly closes the connection at the point i  
press  
CTRL+C.

Now consider the following with memcached in eval, i have changed the  
above  
configuration to use memcached instead of memc:

- About to connect() to localhost port 81 (#0)
- Trying 127.0.0.1… connected
- Connected to localhost (127.0.0.1) port 81 (#0)

> GET  
> /session/synchronize/da39a3ee5e6b4b0d3255bfef95601890afd80709/da39a3ee5e6b4b0d3255bfef95601890afd80709/abc  
> HTTP/1.1  
> User-Agent: curl/7.19.5 (i486-pc-linux-gnu) libcurl/7.19.5 OpenSSL/0.9.8g  
> zlib/1.2.3.3 libidn/1.15  
> Host: localhost:81  
> Accept: _/_

\< HTTP/1.1 200 OK  
\< Server: nginx  
\< Date: Tue, 16 Feb 2010 10:46:22 GMT  
\< Content-Type: text/plain  
\< Transfer-Encoding: chunked  
\< Connection: close  
\<  
hello!

- Closing connection #0

You can clearly see what’s going on: this is what it should look like.  
Now,  
also consider using the memc module with the eval lines commented out. I  
also  
had to comment out the echo lines because otherwise it won’t pass to  
memcache:

- About to connect() to localhost port 81 (#0)
- Trying 127.0.0.1… connected
- Connected to localhost (127.0.0.1) port 81 (#0)

> GET  
> /session/synchronize/da39a3ee5e6b4b0d3255bfef95601890afd80709/da39a3ee5e6b4b0d3255bfef95601890afd80709/abc  
> HTTP/1.1  
> User-Agent: curl/7.19.5 (i486-pc-linux-gnu) libcurl/7.19.5 OpenSSL/0.9.8g  
> zlib/1.2.3.3 libidn/1.15  
> Host: localhost:81  
> Accept: _/_

\< HTTP/1.1 201 Created  
\< Server: nginx  
\< Date: Tue, 16 Feb 2010 10:50:31 GMT  
\< Content-Type: text/plain  
\< Content-Length: 8  
\< Connection: close  
\<  
STORED

- Closing connection #0

There is also a difference in HTTP response code and body if only using  
set,  
here is what i found:

memc returns code=HTTP 201 body=STORED  
memcached returns code=HTTP 200 body= ← this is empty

Can the contributers of the modules please tell us something about this  
behaviour? I’m using the latest stable 0.7 nginx and modules.

Many many thanks in advance

Cheers,

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 16, 2010, 12:12pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/2 "2010-02-16T12:12:50Z")

</div>

Hi Markus,  
could you check if the same happens with agentzh’s modified eval module?

> **[GitHub - openresty/nginx-eval-module: A module for evaluating memcached or...](https://github.com/openresty/nginx-eval-module)**
>
> A module for evaluating memcached or proxy response into variable - GitHub - openresty/nginx-eval-module: A module for evaluating memcached or proxy response into variable

Best regards,  
Piotr S. \< removed\_email\_address@domain.invalid \>

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 16, 2010, 12:48pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/3 "2010-02-16T12:48:32Z")

</div>

Hello Piotr,

Thanks for you reply but i am already using the latest module which  
allows for  
multiple eval blocks in a single location, works fine by the way.

Cheers,

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 16, 2010, 1:08pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/4 "2010-02-16T13:08:26Z")

</div>

Hello Markus,

> Thanks for you reply but i am already using the latest module which allows  
> for  
> multiple eval blocks in a single location, works fine by the way.

Yes, I’m aware of that. But the version you’re using (official one)  
doesn’t  
include changes made by agentzh, hence my request for you to check if it  
works with memc. Please note that this modification was made before  
multiple  
evel blocks were added, so it will work with only one block.

Anyway, if memc will work fine with modifications made by agentzh, then  
you  
should ask Valery to include them in official release.

Best regards,  
Piotr S. \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 16, 2010, 1:08pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/5 "2010-02-16T13:08:26Z")

</div>

Hi,

There is a small mistake in the first post; the standard memcache module  
does  
not support commands, hence it cannot be used to set variables. The  
issue with  
the 3rd-party memc module persists though.

Cheers,

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 9:51am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/6 "2010-02-17T09:51:00Z")

</div>

Hello Piotr,

Sorry for the late reply, the ML is not very happy with me i guess for i  
didn’t get this in my mailbox. I’ve downloaded and compiled agentzh’s  
eval  
module.

What comes out:

Well, agentzh’s latest eval source - directly taken from the most recent  
commit - not only works with multiple eval blocks, it also neatly allows  
the  
memc module to close it’s connection to the memcache server. So it seems  
it is  
not memc issue but has to do with the eval module.

First i used Valery’s source from his github, it seems the source at the  
time  
did allow for multiple eval blocks but could not let the connection  
close.

The question now is, will their come an `official` source for the eval  
module?  
Or may we assume Valery’s page [1](http://www.grid.net.ru/nginx/eval.en.html) is the one point to download from?

Thanks Piotr for the tip!

Regards,

> Yes, I’m aware of that. But the version you’re using (official one) doesn’t  
> include changes made by agentzh, hence my request for you to check if it  
> works with memc. Please note that this modification was made before multiple  
> evel blocks were added, so it will work with only one block.
> 
> Anyway, if memc will work fine with modifications made by agentzh, then you  
> should ask Valery to include them in official release.
> 
> Best regards,  
> Piotr S. \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 11:00am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/7 "2010-02-17T11:00:40Z")

</div>

Hi Markus,

> Well, agentzh’s latest eval source - directly taken from the most recent  
> commit - not only works with multiple eval blocks,

This must be some nice side-effect 🙂 As far as I know agentzh intended  
to  
make eval module work with ngx\_drizzle / ngx\_postgres / ngx\_oracle, he  
didn’t mention anything about multiple blocks to me.

> it also neatly allows the  
> memc module to close it’s connection to the memcache server. So it seems  
> it is  
> not memc issue but has to do with the eval module.

Great!

> The question now is, will their come an `official` source for the eval  
> module?  
> Or may we assume Valery’s page [1] is the one point to download from?

You mean version with agentzh’s modification?  
I don’t think so, unless Valery will pull the changes into his  
repository 😉

Best regards,  
Piotr S. \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 12:55pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/8 "2010-02-17T12:55:25Z")

</div>

Sounds good!

But Valery, i previously used your new eval module that allows for  
multiple  
blocks. That version had an issue with not letting memc\_pass close the  
memcached connection when setting values (getting values worked  
properly).

Now, for the moment, i use agentzh’s eval which for some reason also  
allows  
for multiple eval blocks and does let memc\_pass close the connection.

I’d prefer to use your release if a fix could be made that closes the  
connection with the memcache server.

Regards,

> avoided, if an appropriate state machine is implemented.
> 
> As soon as these issues are resolved, I’ll accept this code.

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

<div class="post-metadata">

**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 1:20pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/9 "2010-02-17T13:20:00Z")

</div>

----- Markus J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I’d prefer to use your release if a fix could be made that closes the  
> connection with the memcache server.

I’ll try to fix this problem.

> > 
> 
> Markus J. - Technisch Architect - Buyways BV  
> [http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
> 050-8536620 / 06-50258350
> 
> * * *
> 
> nginx mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [mailman.nginx.org archive](http://nginx.org/mailman/listinfo/nginx)

## –

Regards,  
Valery K.

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 1:27pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/10 "2010-02-17T13:27:02Z")

</div>

On Wed, Feb 17, 2010 at 7:07 PM, Valery K.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> In particular I don’t like the presence of “eval\_subrequest\_in\_memory” directive at all, because it specifies which way of internal communication the module needs to use, which doesn’t make any sense for end user.

Thanks for replying to my pull request (although indirectly). Yeah, I  
don’t like the name of that directive as well. I chose that just  
because I can’t find a better name at that moment 😛

> Second, the contributed code allocates a buffer and uses it in order to assemble the output of subrequest in it. This allocation can be totally avoided, if an appropriate state machine is implemented.

I just copied (almost) the way that ngx\_http\_upstream does buffered  
outputing 😉 To be honest, I didn’t and don’t see how that allocation  
can be totally avoided for general use cases. Silly me! 😛

> As soon as these issues are resolved, I’ll accept this code.

It’ll be great if you provide some more elaborate suggestions or even  
patches to my patches if you do have the tuits 🙂

Just as Piotr mentioned ealier, the initial motivation for my ngx\_eval  
branch is to provide support for ngx\_drizzle + ngx\_rds\_json. Adding  
subrequest-in-memory support to every content handler/upstream handler  
_with_ output filter support is boring and no fun. So I chose to fix  
ngx\_eval rather than my content handler/upstream modules 😉

Thanks!  
-agentzh

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 12:17pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/11 "2010-02-17T12:17:56Z")

</div>

> > The question now is, will their come an `official` source for the eval  
> > module?  
> > Or may we assume Valery’s page [1] is the one point to download from?
> 
> You mean version with agentzh’s modification?  
> I don’t think so, unless Valery will pull the changes into his repository 😉

I appreciate your interest in my software, but the problem with this  
contributed code at the moment is that it is not as efficient as it  
could possibly be and it is not universal enough.

In particular I don’t like the presence of “eval\_subrequest\_in\_memory”  
directive at all, because it specifies which way of internal  
communication the module needs to use, which doesn’t make any sense for  
end user.

Second, the contributed code allocates a buffer and uses it in order to  
assemble the output of subrequest in it. This allocation can be totally  
avoided, if an appropriate state machine is implemented.

As soon as these issues are resolved, I’ll accept this code.

–  
Regards,  
Valery K.

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 17, 2010, 1:27pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/12 "2010-02-17T13:27:37Z")

</div>

Great!! Let us know, we’ll test it as soon as we can and report back on  
it.

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 18, 2010, 12:48pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/13 "2010-02-18T12:48:53Z")

</div>

Hi Markus,

> Anyway, i wonder if creating a module on my own would be easier in the  
> end,  
> dealing with many conditional operators and eval blocks inside the  
> configuration is either quite a challenge or not feasible.

It would actually help if you would share with us what are you trying to  
achieve 😉

Best regards,  
Piotr S. \< [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) \>

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 18, 2010, 11:56am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/14 "2010-02-18T11:56:12Z")

</div>

Hi,

I’ve tested a bit further and the both agentzh and Valery’s module do  
not  
close the connection inside an interal location called by  
echo\_subrequest. In  
that internal location i try to use proxy\_pass to fetch an uuid from a  
backend.

Earlier i had that block of code in a larger location but due to various  
module’s order of execution i tried to split the parts into internal  
location.

I immediately got the same problem as before. I’ve then tried to use the  
other  
module but it doesn’t work either.

Anyway, i wonder if creating a module on my own would be easier in the  
end,  
dealing with many conditional operators and eval blocks inside the  
configuration is either quite a challenge or not feasible.

Cheers,

> I’ll try to fix this problem.

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 19, 2010, 11:31am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/15 "2010-02-19T11:31:01Z")

</div>

Hi,

In the end, i need two pieces of server side logic:

1. HTTP request filter that looks up a key in memcache (specified in a  
cookie). Then, an additional lookup is required and finally either the  
URL can  
be rewritten or the original cookie can be overwritten.

In pseudo:  
request.cookie.token = memcache\_get(memcache\_get(request.cookie.token));

Of course, some validation checks need to be executed such as verifying  
if the  
client’s IP address is actually linked to the token.

This part already works and uses two eval blocks.

1. A HTTP request with multiple parameters needs to be processed and a  
cookie  
needs to be set (eval) which value is a random hash generated by some  
backend  
(eval), that value then will be stored in memcache as well (eval) as a  
HTTP  
specified token. This step is a token synchronization process that  
initializes  
a session so it can be called using the logic above.

This second part is filled with checks, validations etc and is hard to  
implement because of order of exection (eval before rewrite). But i  
really  
need rewrite’s conditional statement a lot of times. Splitting it all up  
in  
seperate named locations is quite a challenge.

Doing all this in the config would be nice but on the other hand making  
a  
module for it would be even better. It would be some sort of combination  
of  
the memcache module and user\_id module.

Cheers,

> It would actually help if you would share with us what are you trying to  
> achieve 😉

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

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**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 24, 2010, 2:52pm UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/16 "2010-02-24T14:52:41Z")

</div>

Yes, i can provide a snippet. In the end i have decided to abandon the  
project  
of doing it in configuration. It is extremely hard to try and write  
imperative  
code in a declarative language; although we do have the if operator [1](http://wiki.nginx.org/IfIsEvil),  
working with it is more troublesome than ever before 😉

We will now try and build a module for our purpose, at least, i hope so.

Anyway, here is a snippet to reproduce a non -closing connection using  
eval in  
a named location called by echo\_exec - it gets complicated indeed.

```
location /test
{
  echo_exec @initialize;
}

location @initialize
{
  eval_override_content_type 'text/plain';

  eval $id
  {
    rewrite ^(.*)$ /id;
    proxy_pass http://data-1:8080;
  }
}

```

This will fail and also fail with a memc\_pass call. However, it will  
work if  
you replace the echo\_exec call with the entire contents of the named  
location.

Even this little piece of code gave me a hard time; imagine how some 50  
lines  
using various eval blocks, proxy\_pass and memc\_pass directives and many  
evil  
if operators 😉

Anyway, thanks for all the support on the way!

Regards,

On Wednesday 24 February 2010 05:26:04 agentzh wrote:

> tested a bit further and the both agentzh and Valery’s module do not
> 
> > close the connection inside an interal location called by echo\_subrequ

Markus J. - Technisch Architect - Buyways BV  
[http://www.linkedin.com/in/markus17](http://www.linkedin.com/in/markus17)  
050-8536620 / 06-50258350

---

<div class="post-metadata">

**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 25, 2010, 3:03am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/17 "2010-02-25T03:03:38Z")

</div>

On Wed, Feb 24, 2010 at 9:52 PM, Markus J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Yes, i can provide a snippet. In the end i have decided to abandon the project  
> of doing it in configuration. It is extremely hard to try and write imperative  
> code in a declarative language; although we do have the if operator [1](http://wiki.nginx.org/IfIsEvil),  
> working with it is more troublesome than ever before 😉

Sigh. I’m sure there’s some bug in one of those modules that you were  
using. I’m afraid you’ll also have a hard time in writing a module  
yourself because the nginx’s core does not have a nice API 😉

> We will now try and build a module for our purpose, at least, i hope so.
> 
> Anyway, here is a snippet to reproduce a non -closing connection using eval in  
> a named location called by echo\_exec - it gets complicated indeed.

I’ve reproduced this connection hang using the following (slightly  
modified) version of config:

location /test  
{  
echo\_exec @initialize;  
}

location @initialize  
{  
eval\_override\_content\_type ‘text/plain’;

```
 eval $id
 {
   #rewrite ^(.*)$ /id;
   proxy_pass http://127.0.0.1:$server_port/id;
 }
 echo $id;

```

}  
location /id {  
echo hi;  
}

Our Test::Nginx::Socket module reports a timeout that the nginx server  
does not close the client connection in time.

But I’ve found a work-around by avoid using named location:

location /test  
{  
echo\_exec /initialize;  
}

location /initialize  
{  
internal;  
eval\_override\_content\_type ‘text/plain’;

```
 eval $id
 {
   #rewrite ^(.*)$ /id;
   proxy_pass http://127.0.0.1:$server_port/id;
 }
 echo $id;

```

}  
location /id {  
echo hi;  
}

Then GET /test gives the output as expected:

```
 hi

```

It seems to be a named location issue. According to the implementation  
in the nginx core, “named location” is quite buggy. And we’ve run into  
some other issues earlier as well. So my suggestion is to use the  
“internal” directive combined with normal locations for such kind of  
things.

> Even this little piece of code gave me a hard time; imagine how some 50 lines  
> using various eval blocks, proxy\_pass and memc\_pass directives and many evil  
> if operators 😉

I do understand the frustration. Without considerable knowledge to the  
nginx internals, it’s quite difficult to diagnose issues when things  
go wrong.

> Anyway, thanks for all the support on the way!

You’re always welcome to report detailed issues to the list and please  
don’t give up config file scripting 😉

> 

Well, the “if” directive in the http rewrite module is not that evil  
as long as we know how it works. I believe the evilness of “if” has  
been exaggerated. It just not works the way you’re used to in most of  
other languages like C and Perl.

We’ve been enjoying “if” in our nginx.conf for something big:

```
http://agentzh.org/misc/nginx.conf

```

I’ve given some hints regarding “if”'s behavior here:

[http://forum.nginx.org/read.php?2,25197,25197](http://forum.nginx.org/read.php?2,25197,25197)

It’s not that hard to predict how it works 😉

On the other hand, I’d say named locations are indeed evil because it  
does not clear the request object like normal locations and may lead  
to consequences that are _very_ hard to predict.

Cheers,  
-agentzh

---

<div class="post-metadata">

**Author:** ![mflive](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/e99b99/32.png) [@mflive](https://www.ruby-forum.com/u/mflive)\
**Post date:** [February 24, 2010, 5:26am UTC](https://www.ruby-forum.com/t/issue-with-3rd-party-memc-and-eval-modules/183545/18 "2010-02-24T05:26:35Z")

</div>

On Thu, Feb 18, 2010 at 6:55 PM, Markus J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> I’ve tested a bit further and the both agentzh and Valery’s module do not  
> close the connection inside an interal location called by echo\_subrequest.

Can you provide a minimized config snippet that can reproduce this  
problem? It’s getting a bit complicated it seems 😉

BTW, I’m a big fan of nginx.conf scripting myself 😉

Cheers,  
-agentzh