[ACAP3] How and where to install libs using the dockerfile?

[c-hristian]

Please bear with me as i'm new to this sort of development and don't fully know the terminology as well.

I'm trying to understand how to install a lib with the Dockerfile for the app to include.

For example, i'm wanting to install mosquitto and in my dockerfile i have something like:

RUN apt-get update && apt-get install -y \
    software-properties-common \
    && add-apt-repository ppa:mosquitto-dev/mosquitto-ppa \
    && apt-get update \
    && apt-get install -y \
    build-essential \
    mosquitto \
    libmosquitto-dev \
    # other packages \
    && rm -rf /var/lib/apt/lists/*

This does install mosquitto on the container but whenever i go and build the acap application it cannot find the mosquitto lib

Error:

#23 2.250 /usr/lib/gcc-cross/arm-linux-gnueabihf/9/../../../../arm-linux-gnueabihf/bin/ld: cannot find -lmosquitto
#23 2.253 collect2: error: ld returned 1 exit status
#23 2.258 make: *** [Makefile:46: orbit_acap] Error 1

[github-actions[bot]]

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[rocky-ji]

if you are using ACAP3 or ACAP native SDK, you need crosscompile the library, refer to these example openssl_curl_example:

https://github.com/AxisCommunications/acap-native-sdk-examples/tree/main/utility-libraries
https://github.com/AxisCommunications/acap3-examples/tree/main/utility-libraries/openssl_curl_example

[pppaulpeter]

what if i am using the ACAP 4?

[rocky-ji]

already include for ACAP 4: https://github.com/AxisCommunications/acap-native-sdk-examples/tree/main/utility-libraries
if

[pppaulpeter]

thanks, it is not easy as i thought

[daniel-falk]

Do you mind if I take a step back and ask what do you want to use the MQTT client for? @c-hristian @pppaulpeter

Perhaps you can do what you want to by using the axevent library already included in the SDKs and then configure event forwarding to the cameras built-in MQTT broker? This would save you both the energy of cross-compiling the client library, but also of building a user interface for configuration since that can be done in the cameras existing UI. The downside is of course flexibility, and there might (or might not) be more manual configuration needed from the user.

I have created a video here where I show how to connect an ACAPs ax-events with the onboard MQTT broker. You can both send and receive messages using this approach.