Add support for detecting configuration file changes via file system
notifications (fsnotify). Watches are added for the whole directory
chain (up to root directory) so that all changes (even directory
renames) affecting the given configuration file path are captured.
Previously dynamic (re-)configuration of nfd-worker was implemented by
(re-)reading the configuration file on every labeling pass. This was
simple and effective, even if a bit wasteful. However, it didn't provide
asynchronous configuration updates that will be required for e.g.
controlling the "sleep-interval" parameter dynamically which will be
implemented by later patches.
When updating node labels and annotations use JSON patches instead of
doing a read-modify-write on the whole node object. Patching is already
being used in managing extended resources so some of the existing code
was re-usable.
This patch should mitigate the problem of node update failures caused by
race conditions (a change in the node object between our read and write)
resulting e.g. in errors/restarts in nfd worker pods.
Update go dep golang.org/x/text
CVE-2020-14040
golang.org/x/text: possibility to trigger an infinite loop in
encoding/unicode could lead to crash
Reported on Bug 1853652
Signed-off-by: Carlos Eduardo Arango Gutierrez <carangog@redhat.com>
