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Create standalone classes falco_engine/falco_outputs that can be embedded in other programs. falco_engine is responsible for matching events against rules, and falco_output is responsible for formatting an alert string given an event and writing the alert string to all configured outputs. falco_engine's main interfaces are: - load_rules/load_rules_file: Given a path to a rules file or a string containing a set of rules, load the rules. Also loads needed lua code. - process_event(): check the event against the set of rules and return the results of a match, if any. - describe_rule(): print details on a specific rule or all rules. - print_stats(): print stats on the rules that matched. - enable_rule(): enable/disable any individual rule. New falco command line option -D allows you to disable one or more rules on the command line. falco_output's main interfaces are: - init(): load needed lua code. - add_output(): add an output channel for alert notifications. - handle_event(): given an event that matches one or more rules, format an alert message and send it to any output channels. Each of falco_engine/falco_output maintains a separate lua state and loads separate sets of lua files. The code to create and initialize the lua state is in a base class falco_common. falco_engine no longer logs anything. In the case of errors, it throws exceptions. falco_logger is now only used as a logging mechanism for falco itself and as an output method for alert messages. (This should really probably be split, but it's ok for now). falco_engine contains an sinsp_evttype_filter object containing the set of eventtype filters. Instead of calling m_inspector->add_evttype_filter() to add a filter created by the compiler, call falco_engine::add_evttype_filter() instead. This means that the inspector runs with a NULL filter and all events are returned from do_inspect. This depends on draios/sysdig#633 which has a wrapper around a set of eventtype filters. Some additional changes along with creating these classes: - Some cleanups of unnecessary header files, cmake include_directory()s, etc to only include necessary includes and only include them in header files when required. - Try to avoid 'using namespace std' in header files, or assuming someone else has done that. Generally add 'using namespace std' to all source files. - Instead of using sinsp_exception for all errors, define a falco_engine_exception class for exceptions coming from the falco engine and use it instead. For falco program code, switch to general exceptions under std::exception and catch + display an error for all exceptions, not just sinsp_exceptions. - Remove fields.{cpp,h}. This was dead code. - Start tracking counts of rules by priority string (i.e. what's in the falco rules file) as compared to priority level (i.e. roughtly corresponding to a syslog level). This keeps the rule processing and rule output halves separate. This led to some test changes. The regex used in the test is now case insensitive to be a bit more flexible. - Now that draios/sysdig#632 is merged, we can delete the rules object (and its lua_parser) safely. Finally, fix most memory leaks found by valgrind: - falco_configuration wasn't deleting the allocated m_config yaml config. - several ifstreams were being created simply to test which falco config file to use. - In the lua output methods, an event formatter was being created using falco.formatter() but there was no corresponding free_formatter(). This depends on changes in draios/sysdig#640.
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