3.18. Checking System Events This Ruby example retrieves logged system events. # In order to ensure that no events are lost, it is recommended to write # the index of the last processed event, in persistent storage. # Here, it is stored in a file called `index.txt`. In a production environment, # it will likely be stored in a database. INDEX_TXT = 'index.txt'.freeze def write_index(index) File.open(INDEX_TXT, 'w') { |f| f.write(index.to_s) } end def read_index return File.read(INDEX_TXT).to_i if File.exist?(INDEX_TXT) nil end # This is the function that is called to process the events. It prints # the identifier and description of each event. def process_event(event) puts("#{event.id} - #{event.description}") end # Find the root of the tree of services: system_service = connection.system_service # Find the service that manages the collection of events: events_service = system_service.events_service # If no index is stored yet, retrieve the last event and start with it. # Events are ordered by index, in ascending order. `max=1` retrieves only one event, # the last event. unless read_index events = events_service.list(max: 1) unless events.empty? first = events.first process_event(first) write_index(first.id.to_i) end end # This loop retrieves the events, always starting from the last index. It waits # before repeating. The `from` parameter specifies that you want to retrieve # events that are newer than the last index that was processed. Note: the `max` # parameter is not used, so that all pending events will be retrieved. loop do sleep(5) events = events_service.list(from: read_index) events.each do |event| process_event(event) write_index(event.id.to_i) end end For more information, see EventsService:list .

Commands:
In order to ensure that no events are lost, it is recommended to write the index of the last processed event, in persistent storage. Here, it is stored in a file called `index.txt`. In a production environment, it will likely be stored in a database. INDEX_TXT = 'index.txt'.freeze def write_index(index) File.open(INDEX_TXT, 'w') { |f| f.write(index.to_s) } end def read_index return File.read(INDEX_TXT).to_i if File.exist?(INDEX_TXT) nil end This is the function that is called to process the events. It prints the identifier and description of each event. def process_event(event) puts("#{event.id} - #{event.description}") end Find the root of the tree of services: system_service = connection.system_service Find the service that manages the collection of events: events_service = system_service.events_service If no index is stored yet, retrieve the last event and start with it. Events are ordered by index, in ascending order. `max=1` retrieves only one event, the last event. unless read_index events = events_service.list(max: 1) unless events.empty? first = events.first process_event(first) write_index(first.id.to_i) end end This loop retrieves the events, always starting from the last index. It waits before repeating. The `from` parameter specifies that you want to retrieve events that are newer than the last index that was processed. Note: the `max` parameter is not used, so that all pending events will be retrieved. loop do sleep(5) events = events_service.list(from: read_index) events.each do |event| process_event(event) write_index(event.id.to_i) end end