x5/IDEAS.md

   1 IPC
   2 ---
   3
   4 ### 1 file per sensor
   5 A sensor writes to a file, bar reads it.
   6
   7 #### problems
   8 - Race condition: a sensor's message needs multiple `write` calls to complete
   9   and bar reads in between those calls.
  10
  11 This might not be so bad in practice, since we expect sensor messages to be
  12 small and this to complete in a single `write` call.
  13
  14
  15 ### 1 pipe per sensor
  16 A sensor produces a message to a named pipe, bar consumes it.
  17
  18 #### problems
  19 - Cannot accommodate multiple readers (besides bar, I want other tools to be
  20   able to read sensor data, like the `today` script (akin to `motd`));
  21 - Writer blocked when no consumers, though this is irrelevant since only 1
  22   consumer is possible :)
  23
  24
  25 ### N pipes per sensor
  26 A sensor monitors a `subscribers` directory for named pipes and produces
  27 messages for all subscribers.
  28
  29 #### problems
  30 - Reader blocked (which is fine for bar, but not for today/motd)
  31
  32
  33 ### 1 file + lock per sensor
  34
  35 #### problems
  36 - Lock contentions
  37
  38
  39 ### 1 pipe + 1 file per sensor
  40 A sensor writes message to file, then to pipe, bar reads pipe, others can read
  41 file.