Getting librdkafka builtin features

[maxm86545]

Description

Problem

builtin.features: gzip, snappy, ssl, sasl, regex, lz4, sasl_gssapi, sasl_plain, sasl_scram, plugins, zstd, sasl_oauthbearer, http, oidc.
https://github.com/edenhill/librdkafka/blob/b47da0e4eec900d9cb091d2f524e957505dbb513/CONFIGURATION.md
It is not possible to detect the available features of librdkafka using custom PHP code. I can't dynamically manage librdkafka options depending on the environment.

Solution

• librdkafka build information in phpinfo.
• There is a constant with librdkafka build information.
• There is a check function (???).

Hint: builtin_features/BUILT_WITH https://github.com/edenhill/librdkafka/blob/b47da0e4eec900d9cb091d2f524e957505dbb513/src/rdkafka.c#L2544

[arnaud-lb]

Thank you for this request.

CONFIGURATION.md suggests that applications can/should read the default value of the builtin.feature setting to get the list of available features: https://github.com/edenhill/librdkafka/blob/b47da0e4eec900d9cb091d2f524e957505dbb513/CONFIGURATION.md?plain=1#L6 :

Property	C/P	Range	Default	Importance	Description
builtin.features	*		gzip, snappy, ssl, sasl, regex, lz4, sasl_gssapi, sasl_plain, sasl_scram, plugins, zstd, sasl_oauthbearer, http, oidc	low	Indicates the builtin features for this build of librdkafka. An application can either query this value or attempt to set it with its list of required features to check for library support. Type: CSV flags

As a confirmation for this, the kcat tool does exactly that: https://github.com/edenhill/kcat/blob/3ffe04f170cebf5f2ab86accd7581b076eb81619/kcat.c#L1293-L1327

Currently php-rdkafka doesn't implement Conf::get(), but we can still read configuration values through Conf::dump() :

$conf = new RdKafka\Conf();
$features = $conf->dump()['builtin.features'];

I've created a separate issue for the get() method: #527