View Source Implementation

Implementation

Ecron uses an efficient approach to manage job execution times and intervals:

1. The top supervisor ecron_sup starts first.
2. Then ecron_sup starts a child ecron (gen_server worker).
3. ecron will look for the configuration {local_jobs, Jobs} at initialization.
4. For each crontab job found, determine the next time in the future that each command must run.
5. Place those commands in the ordered_set ETS with their {NextCorrespondingTime, Name} to run as the key.
6. Enter ecron's main loop:
   • Examine the task entry at the head of the ETS, compute how far in the future it must run.
   • Sleep for that period of time using the gen_server timeout feature.
   • On awakening and after verifying the correct time, execute the task at the head of the ETS (spawn in background).
   • Delete the old key in ETS.
   • Determine the next time in the future to run this command and place it back in the ETS at that time value.

Additionally, you can use ecron:statistic(Name) to see the job's latest 16 results and execution times.

flowchart TD
    A[ecron_sup] -->|starts| B[ecron]
    
    subgraph initialization
    B -->|init| C[ets:new - ordered_set]
    C -->|read config| D[local_jobs]
    D -->|calculate times| E["ets:insert with {NextTriggeredTime, Name}"]
    end
    
    subgraph main_loop
    E -->|loop| F[Get first entry from ETS]
    F -->|sleep until time| G["Execute(spawn) job in background"]
    G -->|delete old key| H[Calculate new time]
    H -->|"ets:insert new {NextTriggeredTime, Name}"| E
    end