This fixes a bug in the CLI handling of node lookup failures when
querying allocation and FS endpoints.
Allocation and FS endpoint are handled by the client; one can query the
relevant client directly, or query a server to have it forwarded
transparently to relevant client. Querying the client directly is
benefecial to avoid loading servers with IO.
As an optimization, the CLI attempts to query the client directly, but
then falls back to using server forwarding path if it encounters network
or connection errors (e.g. clients are locked down or in a separate
inaccessible network).
Here, we fix a bug where if the CLI fails to find to lookup the client
details because it lacks ACL capability or other unexpected reasons, the
CLI will not go through fallback path.
Closing the frames chan is the only race-free way to signal to receivers
that all frames have been sent and no errors have occurred.
If EOF is sent on error chan receivers may not receive the last frame
(or frames since the chan is buffered) before receiving the error.
Closing frames is the idiomatic way of signaling there is no more data
to be read from a chan.
This PR enhances the API package by having client only RPCs route
through the server when they are low cost and for filesystem access to
first attempt a direct connection to the node and then falling back to
a server routed request.
Fixes#3013
It's a little weird that Client now has a method for returning a
NewClient, but it's a convenient way to dedupe the logic to
connect-directly-to-a-node which is nontrivial and had sutble
differences between locations.
