Create System Log record, when stale semaphore is discovered or hit

1. when somebody hits a semaphore and sees error message log it into "System Log" with "Error" Log Level - 0.5h
2. add following columns to "Semaphores" table: - 0.5h
   • MainIDs - db type: text; comma-separated list of IDs
   • UserId - db type: int
   • IpAddress - db type: varchar(15)
   • Hostname - db type: varchar(255)
   • LogRequestURI - db type: varchar(255)
   • Backtrace - db type: longtext;
3. add following setting in the "System Settings" sub-section in the "Configuration > Website > Advanced" section: - 0.5h
   • name: "SemaphoreLifetime"
   • title: "Semaphore Inactivity Timeout (seconds)"
   • default: 300 (means 5 minutes)
4. create "adm:OnDeleteStaleSemaphores" event, that will: - 1.5h
   • get records from "Semaphores" table, where "Semaphores.Timestamp + {SemaphoreLifetime}

     > UNIX_TIMESTAMP()"

   • if none found, then exit
   • for each found record:
     • create record in "SystemLog" table (using "$this->Application->log" method) where:
       • the "setLogField" method will be used to replace "LogHostname", "LogRequestSource", "LogRequestURI", "LogUserId", "IpAddress" and "LogSessionKey" field values with one, that Semaphore has
       • the "addTrace" method will be used to add trace from semaphore
       • the "setUserData" method will be used to store: value of "MainIDs" field, semaphore creation time, semaphore removal time
       • "Log Level" would be "error"
       • "Message" would be "Stale semaphore discovered"
       • goal is to make that record look like it was created along with semaphore creation
     • delete semaphore record
   • turn "adm:OnDeleteStaleSemaphores" event into a scheduled task, that will run each 5 minutes - 0.5h

Quote: 3.5h*1.4=5h