Setup to use SASL OAuthbearer with Azure AAD token

[minhdn90]

I'm modifying producer.cpp of librdkafka-1.9.2 to test using OAuthbearer token from Azure AAD to send data to Azure Event Hub (Standard tier, Kafka surface enabled).
The modified example compiles but keeps printing

mnguyen@LONL110875:~/librdkafka-1.9.2/examples$ ./producer_cpp my-evh-namespace.servicebus.windows.net:9093 my-evh
%7|1672702528.337|SASL|rdkafka#producer-1| [thrd:app]: Selected provider OAUTHBEARER (builtin) for SASL mechanism OAUTHBEARER
%7|1672702528.337|BRKMAIN|rdkafka#producer-1| [thrd::0/internal]: :0/internal: Enter main broker thread
%7|1672702528.337|BROKER|rdkafka#producer-1| [thrd:app]: sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bootstrap: Added new broker with NodeId -1
%7|1672702528.337|CONNECT|rdkafka#producer-1| [thrd:app]: sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bootstrap: Selected for cluster connection: bootstrap servers added (broker has 0 connection attempt(s))
%7|1672702528.337|BRKMAIN|rdkafka#producer-1| [thrd:sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bo]: sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bootstrap: Enter main broker thread
%7|1672702528.337|CONNECT|rdkafka#producer-1| [thrd:sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bo]: sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bootstrap: Received CONNECT op
%7|1672702528.337|STATE|rdkafka#producer-1| [thrd:sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bo]: sasl_plaintext://my-evh-namespace.servicebus.windows.net:9093/bootstrap: Broker changed state INIT -> TRY_CONNECT
%7|1672702528.337|INIT|rdkafka#producer-1| [thrd:app]: librdkafka v1.9.2 (0x10902ff) rdkafka#producer-1 initialized (builtin.features snappy,ssl,sasl,regex,lz4,sasl_gssapi,sasl_plain,sasl_scram,plugins,sasl_oauthbearer, GCC GXX PKGCONFIG INSTALL GNULD LDS C11THREADS LIBDL PLUGINS SSL SASL_CYRUS HDRHISTOGRAM SYSLOG SNAPPY SOCKEM SASL_SCRAM SASL_OAUTHBEARER CRC32C_HW, debug 0x246)
% Type message value and hit enter to produce message.
%7|1672702529.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702530.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702531.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702532.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702533.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702534.337|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702535.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702536.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702537.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702538.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702539.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702540.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702541.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702542.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702543.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702544.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702545.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702546.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702547.338|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702548.339|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection
%7|1672702549.339|CONNECT|rdkafka#producer-1| [thrd:main]: Cluster connection already in progress: no cluster connection

And it doesn't deliver any messages:

Configuration is as follow:
conf->set("security.protocol", "SASL_PLAINTEXT", errstr);
conf->set("sasl.mechanism", "OAUTHBEARER", errstr);
conf->set("sasl.oauthbearer.method", "oidc", errstr);
conf->set("sasl.oauthbearer.client.id", "MY-CLIENT-ID", errstr);
conf->set("sasl.oauthbearer.client.secret", "MY-CLIENT-SECRET", errstr);
conf->set("sasl.oauthbearer.token.endpoint.url", "https://login.microsoftonline.com/{tenantID}/oauth2/v2.0/token", errstr);
conf->set("sasl.oauthbearer.scope", "https://my-evh-namespace.servicebus.windows.net/.default", errstr);
conf->set("debug", "broker,topic,msg,security", errstr);

Same issue occurs if I use SASL_SSL instead of SASL_PLAINTEXT. But test using SAS connection string works fine with the following configuration:
conf->set("security.protocol", "SASL_SSL", errstr);
conf->set("sasl.mechanism", "PLAIN", errstr);
conf->set("sasl.username", "$ConnectionString", errstr);
conf->set("sasl.password", "Endpoint=sb://my-evh-namespace.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=XXXXXXXXXX", errstr);

What am I missing here? Or is this an issue with the library?

[minhdn90]

I have figured it out. For anyone with the same issue, the key here is to install libcurl. For Ubuntu it's libcurl4-openssl-dev
I installed the library then went though the compilation process for librdkafka again. Then the modified example works.