Support namespacing in cache.Store by framing the interface functions
around interface{} and providing a key function to each Store implementation.
Implementation of a fix for #2294.
Watch depends on long running connections, which intervening proxies
may break without the control of the remote server. Specific errors
handled are io.EOF, io.EOF wrapped by *url.Error, http connection
reset errors (caused by race conditions in golang http code), and
connection reset by peer (simply tolerated).
Watches are often established via long-running HTTP GET requests which
will inevitably time out during the normal course of operations. When
the watches time out, an io.EOF or an io.ErrUnexpectedEOF will bubble
up to client components such as StreamWatcher and Reflector. Treat EOF
as a clean watch termination. Treat ErrUnexpectedEOF as a less-clean
but non-fatal watch termination and log the event at the warning level.
This greatly reduces the amount of log noise generated during what is
ultimately normal operation, and adds the flexibility for the operator
to make a distinction between the EOF conditions if so desired (by
adjusting the logging level).
Prepares for the meta object to front multiple underlying types
when TypeMeta and ObjectMeta is split in internal and v1beta3, but
combined in v1beta1 and v1beta2
Allows us to define different watch versioning regimes in the future
as well as to encode information with the resource version.
This changes /watch/resources?resourceVersion=3 to start the watch at
4 instead of 3, which means clients can read a resource version and
then send it back to the server. Clients should no longer do math on
resource versions.
Move a lot of common error logging into better buckets:
glog.Errorf() - Always an error
glog.Warningf() - Something unexpected, but probably not an error
glog.V(0) - Generally useful for this to ALWAYS be visible
to an operator
* Programmer errors
* Logging extra info about a panic
* CLI argument handling
glog.V(1) - A reasonable default log level if you don't want
verbosity
* Information about config (listening on X, watching Y)
* Errors that repeat frequently that relate to conditions
that can be corrected (pod detected as unhealthy)
glog.V(2) - Useful steady state information about the service
* Logging HTTP requests and their exit code
* System state changing (killing pod)
* Controller state change events (starting pods)
* Scheduler log messages
glog.V(3) - Extended information about changes
* More info about system state changes
glog.V(4) - Debug level verbosity (for now)
* Logging in particularly thorny parts of code where
you may want to come back later and check it
Wojciech Tyczynski