Overwrite old data

[git-blame]

I find this package useful in several scenarios. Now I am looking to maintain a rolling log buffer. But I realized that this ring buffer does not overwrite old data like the traditional definition of a ring/circular buffer.

It is simple to implement a Writer wrapper to do this. For example, simply reading some bytes from the read end if needed. But I will have to ensure concurrency because although the buffer's functions are thread-safe, calling them separately are not.

But before I do, I want to confirm that overwriting data is not supported at this time. Or is there a mode I can set that allows this functionality?

[smallnest]

But I realized that this ring buffer does not overwrite old data like the traditional definition of a ring/circular buffer.

Why do you think it does not overwrite old data? Since It is a ringbuffer, it should be reuse the buffer.

[git-blame]

In ringbuffer.Write code, if it is non-blocking, it returns ErrIsFull.

        err = r.setErr(err, true)
        if r.block && (err == ErrIsFull || err == ErrTooMuchDataToWrite) {
...
    if r.block && wrote > 0 {
        r.writeCond.Broadcast()
    }

    return wrote, r.setErr(err, true)

Also, I am testing with hclog which can write to both stderr and a Writer. Using a ringbuffer of 1024 bytes, I see that it has the 1st 1024 bytes of log data. If it is overwriting old data, I expect to see the last 1024 bytes of log.

End of logs on stderr:

...
2025-01-20T14:29:49.665Z [DEBUG] native_plugin: 2025/01/20 14:29:49 [DEBUG] plugin: plugin server: accept unix /tmp/plugin4106242905: use of closed network connection
2025-01-20T14:29:49.665Z [INFO]  plugin process exited: plugin=modules/native_plugin id=499058
2025-01-20T14:29:49.666Z [DEBUG] plugin exited
2025-01-20T14:29:49.666Z [INFO]  Stopping all pipeline plugins

logs in ringbuffer:

2025-01-20T14:29:47.642Z [DEBUG] Loading plugin: export
2025-01-20T14:29:47.642Z [DEBUG] starting plugin: path=modules/analytics_service_plugin args=[modules/analytics_service_plugin]
2025-01-20T14:29:47.644Z [DEBUG] plugin started: path=modules/analytics_service_plugin pid=499052
2025-01-20T14:29:47.644Z [DEBUG] waiting for RPC address: plugin=modules/analytics_service_plugin
2025-01-20T14:29:47.647Z [DEBUG] analytics_service_plugin: plugin address: address=/tmp/plugin1632902623 network=unix timestamp=2025-01-20T14:29:47.647Z
2025-01-20T14:29:47.648Z [DEBUG] using plugin: version=1
2025-01-20T14:29:47.650Z [DEBUG] Adding plugin: export
2025-01-20T14:29:47.650Z [DEBUG] Loading plugin: network_discover
2025-01-20T14:29:47.650Z [DEBUG] starting plugin: path=modules/native_plugin args=[modules/native_plugin]
2025-01-20T14:29:47.651Z [DEBUG] plugin started: path=modules/native_plugin pid=499058
2025-01-20T14:29:47.651Z [DEBUG] waiting for RPC address: plugin=modules/native_plugin
2025-01-20T14:29:47.654Z [DEBUG]

Note by the timestamp, etc. that ringbuffer contains the first logs until it is full. If it is circular, it should contain the last logs.