NULL message headers in CentOS7 on PHP5.6

[douyux]

when test message_headers.php in centos i got following output:

> php message_headers.php
6 messages delivered  
Got message: message 0 | Headers: none  
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /root/test/message_headers.php on line 80  
Got message: message 1 | Headers: none  
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /root/test/message_headers.php on line 80  
Got message: message 2 | Headers: none  
Got message: message 3 | Headers: none  
Got message: message 4 | Headers: none  
Got message: message 5 | Headers: none 

and var_dump($msg->headers) just print UNKNOWN:0

• os: CentOS Linux release 7.6.1810 (Core)
• kernel: 3.10.0-957.1.3.el7.x86_64
• PHP version: 5.6.36
• librdkafka version: v1.5.0
• php-rdkafka version: 4.0.3
• kafka version: 2.12-2.3.1

---

It's confused that message_headers.php is test ok in ubuntu 16.04 with same kafka server and same librdkafka & php-rdkafka version:

> php message_headers.php
6 messages delivered
%4|1599617807.761|CONFWARN|rdkafka#consumer-2| [thrd:app]: Configuration property dr_msg_cb is a producer property and will be ignored by this consumer instance
Got message: message 0 | Headers: key: value
Got message: message 1 | Headers: key1: value1, key2: value2, key3: value3
Got message: message 2 | Headers: gzencoded: gzdata
Got message: message 3 | Headers: none
Got message: message 4 | Headers: none
Got message: message 5 | Headers: none

[nick-zh]

@douyux thx for the report, so when you:

var_dump($msg->headers);

before the array_walk what is the output?

[douyux]

var_dump headers before array_walk output is UNKNOWN:0:

code:

$msg = $topic->consume(0, 1000);
if (!$msg || $msg->err === RD_KAFKA_RESP_ERR__PARTITION_EOF) {
    break;
}
if (RD_KAFKA_RESP_ERR_NO_ERROR !== $msg->err) {
    throw new Exception($msg->errstr(), $msg->err);
}
echo 'var_dump:'; var_dump($msg->headers);
$headersString = isset($msg->headers) ? $msg->headers : [];
array_walk($headersString, function(&$value, $key) {
    if ('gzencoded' === $key) {
        $value = gzdecode($value);
    }
    $value = "{$key}: {$value}";
});
if (empty($headersString)) {
    $headersString = "none";
} else {
    $headersString = implode(", ", $headersString);
}
printf("Got message: %s | Headers: %s\n", $msg->payload, $headersString);

result:

[root@xxx test]# /usr/local/php/bin/php message_headers.php 
6 messages delivered
var_dump:NULL
Got message: message 0 | Headers: none
var_dump:UNKNOWN:0
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /root/test/message_headers.php on line 82
Got message: message 1 | Headers: none
var_dump:UNKNOWN:0
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /root/test/message_headers.php on line 82
Got message: message 2 | Headers: none
var_dump:NULL
Got message: message 3 | Headers: none
var_dump:NULL
Got message: message 4 | Headers: none
var_dump:NULL
Got message: message 5 | Headers: none

[Steveb-p]

@douyux is the PHP version on Ubuntu also PHP 5.6.36?

[nick-zh]

I will try to replicate this when i find some time. Is this happening on PHP7 as well or just PHP5?

[douyux]

ubuntu php version is: 5.6.40，i'm not sure is will happening on php7 and i think this is nothing to do with php version，maybe the sys & build env cause the issue

[douyux]

this dockerfile can reproduce the isse:

FROM centos:7

RUN yum install -y http://rpms.remirepo.net/enterprise/remi-release-7.rpm \
    && yum install -y yum-utils \
    && yum-config-manager --enable remi-php56 \
    && yum install -y php php-cli php-devel php-pear zlib-devel

RUN yum install -y gcc gcc-c++ automake autoconf libtool make

RUN curl -fsSL 'https://github.com/edenhill/librdkafka/archive/v1.5.0.tar.gz' -o rdkafka.tar.gz \
    && mkdir -p rdkafka \
    && tar -xf rdkafka.tar.gz -C rdkafka --strip-components=1 \
    && rm rdkafka.tar.gz \
    && ( \
        cd rdkafka \
        && ./configure \
        && make \
        && make install \
    ) \
    && rm -r rdkafka

RUN pecl install rdkafka-4.0.3 \
    && echo "extension=rdkafka" >> /etc/php.d/rdkafka.ini

RUN echo $'#!/bin/sh \n\
set -e \n\
exec "$@" \n\
' >> /usr/local/bin/php-entrypoint \
    && chmod +x /usr/local/bin/php-entrypoint

RUN cp /usr/lib64/php/modules/rdkafka.so /usr/lib64/php/modules/rdkafka

ENTRYPOINT ["php-entrypoint"]
CMD ["php", "-a"]

docker run on ubuntu16.04:

docker run -it --rm --name message-headers -v "$PWD":/usr/src/myapp -w /usr/src/myapp qt-centos-php php message_headers.php
6 messages delivered
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /usr/src/myapp/message_headers.php on line 82
Got message: message 0 | Headers: none
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /usr/src/myapp/message_headers.php on line 82
Got message: message 1 | Headers: none
PHP Warning:  array_walk() expects parameter 1 to be array, unknown given in /usr/src/myapp/message_headers.php on line 82
Got message: message 2 | Headers: none
Got message: message 3 | Headers: none
Got message: message 4 | Headers: none
Got message: message 5 | Headers: none

[nick-zh]

@douyux awesome thx a lot for this, i will check it out ✌️

[nick-zh]

@douyux so what i can report back for now is, that it works for php:7.x under CentOS7. With the deadline coming closer, with us dropping php:5 support, i am not sure how much effort i want to put into this. I will try to check if i can find out why it behaves differently from Ubuntu, but i can't promise anything.

[douyux]

@nick-zh thanks a lot for the feedback and efforts, it's nice to fix it when you have more free time in the future.