[systemd-devel] Access journal log files within Docker Container using sd-journal API

[Sebastian Borchers]

Hello,

I have a question. I am trying to read journald log files within a
docker container on a host that is using systemd.
Inside the container, systemd is NOT running. I want to use a library
that uses the sd-journal API to read the logs within the container.

I tried the following docker cmd:

/docker run --rm --interactive --tty \//
//        --net host \//
//        //--privileged \//
//        //-v /run:/run \//
//        -v /var:/var \//
//        --mount type=bind,source=/sys/fs/cgroup,target=/sys/fs/cgroup \//
//        --mount type=bind,source=/sys/fs/fuse,target=/sys/fs/fuse \
        myContainer:latest
/

When running my code inside this container, though, the log files are
always empty.
Running the same code on my host machine correctly yields the log files.

I know that just mounting whole /var and --privileged are bad. This is
just a proof of concept.
What am I missing to make this work?

In case its important, this is my code to read log files (library is
go-systemd/sdjournal)

/jr, err := sdjournal.NewJournalReader(sdjournal.JournalReaderConfig{})//
//if err != nil {//
//    return//
//}
buf := make([]byte, 1024)
n, err := jr.Read(buf)
if err != nil {
    if n > 0 {
        println(string(buf[:n]))
    }
    if err == io.EOF {
        println("EOF")
        err = nil
    }
    return
}
println(string(buf[:n]))/

I also tried to supply the path to the log dir:
"/var/log/journal/<machine-id>" in the reader conf, but the result was
the same.
//

Kind regards,

Sebastian

P.S.: This is my first message on this mailing list, sorry if I missed
any rule or best practice.

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