* Add ability to print field names only
Add ability to print field names only instead of all information about
fields (description, etc) using -N cmdline option.
This will be used to add some versioning support steps that check for a
changed set of fields.
* Add an engine version that changes w/ filter flds
Add a method falco_engine::engine_version() that returns the current
engine version (e.g. set of supported fields, rules objects, operators,
etc.). It's defined in falco_engine_version.h, starts at 2 and should be
updated whenever a breaking change is made.
The most common reason for an engine change will be an update to the set
of filter fields. To make this easy to diagnose, add a build time check
that compares the sha256 output of "falco --list -N" against a value
that's embedded in falco_engine_version.h. A mismatch fails the build.
* Check engine version when loading rules
A rules file can now have a field "required_engine_version N". If
present, the number is compared to the falco engine version. If the
falco engine version is less, an error is thrown.
* Unit tests for engine versioning
Add a required version: 2 to one trace file to check the positive case
and add a new test that verifies that a too-new rules file won't be loaded.
* Rename falco test docker image
Rename sysdig/falco to falcosecurity/falco in unit tests.
* Don't pin falco_rules.yaml to an engine version
Currently, falco_rules.yaml is compatible with versions <= 0.13.1 other
than the required_engine_version object itself, so keep that line
commented out so users can use this rules file with older falco
versions.
We'll uncomment it with the first incompatible falco engine change.
