Deprecate `<none>:<none>` and `<none>@<none>` magic strings included in
`RepoTags` and `RepoDigests`.
Produce an empty arrays instead and leave the presentation of
untagged/dangling images up to the client.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Checking if the image creation failed due to IsAlreadyExists didn't use
the error from ImageService.Create.
Error from ImageService.Create was stored in a separate variable and
later IsAlreadyExists checked the standard `err` variable instead of the
`createErr`.
As there's no need to store the error in a separate variable - just
assign it to err variable and fix the check.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
PTR queries with domain names unknown to us are not necessarily invalid.
Act like a well-behaved middlebox and fall back to forwarding
externally, same as we do with the other query types.
Signed-off-by: Cory Snider <csnider@mirantis.com>
...for limiting concurrent external DNS requests with
"golang.org/x/sync/semaphore".Weighted. Replace the ad-hoc rate limiter
for when the concurrency limit is hit (which contains a data-race bug)
with "golang.org/x/time/rate".Sometimes.
Immediately retrying with the next server if the concurrency limit has
been hit just further compounds the problem. Wait on the semaphore and
refuse the query if it could not be acquired in a reasonable amount of
time.
Signed-off-by: Cory Snider <csnider@mirantis.com>
It handles figuring out the UDP receive buffer size and setting IO
timeouts, which simplifies our code. It is also more robust to receiving
UDP replies to earlier queries which timed out.
Log failures to perform a client exchange at level error so they are
more visible to operators and administrators.
Signed-off-by: Cory Snider <csnider@mirantis.com>
forwardExtDNS() will now continue with the next external DNS sever if
co.ReadMsg() returns (nil, nil). Previously it would abort resolving the
query and not reply to the container client. The implementation of
ReadMsg() in the currently- vendored version of miekg/dns cannot return
(nil, nil) so the difference is immaterial in practice.
Signed-off-by: Cory Snider <csnider@mirantis.com>
(*dns.Msg).Truncate() is more intelligent and standards-compliant about
truncating DNS response messages than our hand-rolled version. Fix a
silly fencepost error the max TCP message size: the limit is
dns.MaxMsgSize (65535), full stop.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The TC flag in a DNS message indicates that the sender had to
truncate it to fit within the length limit of the transmission channel.
It does NOT indicate that part of the message was lost before reaching
the recipient. Older versions of github.com/miekg/dns conflated the two
cases by returning ErrTruncated from ReadMsg() if the message was parsed
without error but had the TC flag set. The version of miekg/dns
currently vendored no longer returns an error when a well-formed DNS
message is received which has its TC flag set, but there was some
confusion on how to update libnetwork to deal with this behaviour
change. Truncated DNS replies are no longer different from any other
reply message: they are normal replies which do not need any special-
case handling to proxy back to the client.
Signed-off-by: Cory Snider <csnider@mirantis.com>
