Currently in tests, we have calls to os.Remove and os.RemoveAll where we
don't check the returned error. This hides useful error messages when
tests fail to run, such as "too many open files".
This change checks for more filesystem related errors and calls t.Fatal
if there is an error.
This contains a rewrite to the services layer for exporting and importing. The code this merges to already had a first significant rewrite that moved from special interest processing to plain subscriptions.
This code changes the prior version's dealing with reverse mapping which was based mostly on thresholds and manual pruning, with some sporadic timer usage. This version uses the jetstream branch's code that understands interest and failed deliveries. So this code is much more tuned to reacting to interest changes. It also removes thresholds and goes only by interest changes or expirations based around a new service export property, response thresholds. This allows a service provider to provide semantics on how long a response should take at a maximum.
This commit also introduces formal support for service export streamed and chunked response types send an empty message to signify EOF.
This commit also includes additions to the service latency tracking such that errors are now sent, not only successful interactions. We have added a Status field and an optional Error fields to ServiceLatency.
We support the following Status codes, these are directly from HTTP.
400 Bad Request (request did not have a reply subject)
408 Request Timeout (when system detects request interest went away, old request style to make dependable)..
503 Service Unavailable (no service responders running)
504 Service Timeout (The new response threshold expired)
Signed-off-by: Derek Collison <derek@nats.io>
