ACAP program installation process

[sinnrrr]

I noticed there is a difference between how apps are being installed on the camera.

I had a situation, where logs from one app, haven't been captured, while from another everything worked. I decided to view to systemd unit configuration for these apps and found out that one of them (where logs didn't capture) was launched using init.d and another one normally (full path to binary). That means that everything from stdout goes to init.d and never reaches systemd, which is why we cannot see logs, as they are not put into the journal.

I have noticed one difference between these apps: the manifest.json file is missing in the app package, the logs of which does not being captured. Does this mean that the installer acts differently based on that? In which cases it includes init.d in the unit configuration file of the app, and why use init.d at all if you're using systemd?

[mattias-kindborg-at-work]

Hi @sinnrrr. Are these apps publicly accessible, can I inspect them?

manifest.json is a continuation of package.conf, for more information see the ACAP version 3 documentation. ACAP applications built with newer versions of the ACAP version 3 SDK or ACAP version 4 SDK will use manifest.json as a description of the package. Logs are accessible via http://<ip>/axis-cgi/admin/systemlog.cgi?appname=<app name> where <ip> is the IP address of the Axis device and <app name> is the name/id of the application. Could you please verify that logs for both applications are available using this URI?

[sinnrrr]

I have another camera that have the same app installed there, the logs ARE available there and the systemd service looks as follows:

[Unit]
Description=RR Axis Streamer
After=acap-pre.target
Requires=acap-pre.target
[Service]
Slice=extension-acap.slice
RemainAfterExit=yes
ExecStart=/usr/local/packages/rr_axis_streamer/rr_axis_streamer
Restart=always
User=root
Group=root
[Install]
WantedBy=acap.target

[mattias-kindborg-at-work]

Given that this is the same installed ACAP application, does the firmware version of the two cameras differ?

[sinnrrr]

Yeah, it seems like one camera had 10.12.xx, whilst the other had 10.4.xx (this one didn't show the logs).
Upgrading the firmware worked!

[daniel-falk]

I think the standard for cameras is still to use init.d (even in FW 11.x) which means that stdout is not captured by the system log? To make debugging easier we use a library that logs both to stdout and to the system log, like this:

/* Log a message both to the system logger and to stdout */
void fapp_logger_log(int priority, const char *fmt, ...) {
  va_list args;

  /* Log to stdout */
  va_start(args, fmt);
  printf("%s: ", fapp_logger_level_to_str(priority));
  vprintf(fmt, args);
  printf("\n");
  va_end(args);

  /* Log to system logger */
  va_start(args, fmt);
  vsyslog(priority, fmt, args);
  va_end(args);
}

Some third party libraries logs only to stdout in which case it is much harder to capture the logs.. Manually redirecting the stdout file descriptor is of course possible...

[dsoltysiuk]

Thanks! This makes sense.