1. Table implementations (spec files) can mark the table as 'cachable'.
2. Cached results depend on the shortest/quickest interval of scheduled
queries that act on results of the table.
3. The table API generator blocks caching on index/additional/required
table column options.
This commit contains the features specified in #1390 as well as a
refactoring of the general osquery configuration code.
The API for the config plugins hasn't changed, although now there's a
`genPack` method that config plugins can implement. If a plugin doesn't
implement `genPack`, then the map<string, string> format cannot be used.
The default config plugin, the filesystem plugin, now implements
`genPack`, so existing query packs code will continue to work as it
always has.
Now many other config plugins can implement custom pack handling for
what makes sense in their context. `genPacks` is not a pure virtual, so
it doesn't have to be implemented in your plugin if you don't want to
use it. Also, more importantly, all config plugins can use the standard
inline pack format if they want to use query packs. Which is awesome.
For more information, refer to #1390, the documentation and the doxygen
comments included with this pull requests, as well as the following
example config which is now supported, regardless of what config plugin
you're using:
```json
{
"options": {
"enable_monitor": "true"
},
"packs": {
"core_os_monitoring": {
"version": "1.4.5",
"discovery": [
"select pid from processes where name like '%osqueryd%';"
],
"queries": {
"kernel_modules": {
"query": "SELECT name, size FROM kernel_modules;",
"interval": 600
},
"system_controls": {
"query": "SELECT * FROM system_controls;",
"interval": 600,
"snapshot": true,
},
"usb_devices": {
"query": "SELECT * FROM usb_devices;",
"interval": 600
}
}
},
"osquery_internal_info": {
"version": "1.4.5",
"discovery": [
"select pid from processes where name like '%osqueryd%';"
],
"queries": {
"info": {
"query": "select i.*, p.resident_size, p.user_time, p.system_time, time.minutes as counter from osquery_info i, processes p, time where p.pid = i.pid;",
"interval": 60,
"snapshot": true
},
"registry": {
"query": "SELECT * FROM osquery_registry;",
"interval": 600,
"snapshot": true
},
"schedule": {
"query": "select name, interval, executions, output_size, wall_time, (user_time/executions) as avg_user_time, (system_time/executions) as avg_system_time, average_memory from osquery_schedule;",
"interval": 60,
"snapshot": true
}
}
}
}
}
```
The `osquery_packs` table was modified to remove the superfluous
columns which could already have been found in `osquery_schedule`. Two
more columns were added in their place, representing stats about pack's
discovery query execution history.
Notably, the internal API for the `osquery::Config` class has changed
rather dramatically as apart of the refactoring. We think this is an
improvement. While strictly adhering to the osquery config plugin
interface will have avoided any compatibility errors, advanced users may
notice compilation errors if they access config data directly. All
internal users of the config have obviously been updated. Yet another
reason to merge your code into mainline; we update it for you when we
refactor!
