Monitoring systems and load balancers are usually configured to use HEAD
requests for health monitoring. The /_ping endpoint currently does not
support this type of request, which means that those systems have fallback
to GET requests.
This patch adds support for HEAD requests on the /_ping endpoint.
Although optional, this patch also returns `Content-Type` and `Content-Length`
headers in case of a HEAD request; Refering to RFC 7231, section 4.3.2:
The HEAD method is identical to GET except that the server MUST NOT
send a message body in the response (i.e., the response terminates at
the end of the header section). The server SHOULD send the same
header fields in response to a HEAD request as it would have sent if
the request had been a GET, except that the payload header fields
(Section 3.3) MAY be omitted. This method can be used for obtaining
metadata about the selected representation without transferring the
representation data and is often used for testing hypertext links for
validity, accessibility, and recent modification.
A payload within a HEAD request message has no defined semantics;
sending a payload body on a HEAD request might cause some existing
implementations to reject the request.
The response to a HEAD request is cacheable; a cache MAY use it to
satisfy subsequent HEAD requests unless otherwise indicated by the
Cache-Control header field (Section 5.2 of [RFC7234]). A HEAD
response might also have an effect on previously cached responses to
GET; see Section 4.3.5 of [RFC7234].
With this patch applied, either `GET` or `HEAD` requests work; the only
difference is that the body is empty in case of a `HEAD` request;
curl -i --unix-socket /var/run/docker.sock http://localhost/_ping
HTTP/1.1 200 OK
Api-Version: 1.40
Cache-Control: no-cache, no-store, must-revalidate
Docker-Experimental: false
Ostype: linux
Pragma: no-cache
Server: Docker/dev (linux)
Date: Mon, 14 Jan 2019 12:35:16 GMT
Content-Length: 2
Content-Type: text/plain; charset=utf-8
OK
curl --head -i --unix-socket /var/run/docker.sock http://localhost/_ping
HTTP/1.1 200 OK
Api-Version: 1.40
Cache-Control: no-cache, no-store, must-revalidate
Content-Length: 0
Content-Type: text/plain; charset=utf-8
Docker-Experimental: false
Ostype: linux
Pragma: no-cache
Server: Docker/dev (linux)
Date: Mon, 14 Jan 2019 12:34:15 GMT
The client is also updated to use `HEAD` by default, but fallback to `GET`
if the daemon does not support this method.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
client.checkResponseErr() was hanging and consuming infinite memory
when the serverResp.Body io.Reader returns infinite stream.
This commit prohibits reading more than 1MiB.
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Since Go 1.7, context is a standard package. Since Go 1.9, everything
that is provided by "x/net/context" is a couple of type aliases to
types in "context".
Many vendored packages still use x/net/context, so vendor entry remains
for now.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In some cases a server may return an error on the ping response but
still provide version details. The client should use these values when
available.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Signed-off-by: Victor Vieux <vieux@docker.com>
update cobra and use Tags
Signed-off-by: Victor Vieux <vieux@docker.com>
allow client to talk to an older server
Signed-off-by: Victor Vieux <vieux@docker.com>
The docker client has historically used Transport.TLSClientConfig to set
the scheme for the API client. A recent moved the resolution to use the
http.Transport directly, rather than save the TLSClientConfig state on a
client struct. This caused issues when mutliple calls made with a single
client would have this field set in the http package on pre-1.7
installations. This fix detects the presence of the TLSClientConfig once
and sets the scheme accordingly.
We still don't know why this issue doesn't happen with Go 1.7 but it
must be more deterministic in the newer version.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Signed-off-by: Sean Rodman <srodman7689@gmail.com>
Updated the check for the permission error to use os.IsPermission instead of checking the error string. Also, changed the PermissionDenied method to just a new error.
Fixed a typo in client/request.go
Fixed Error name as specified by Pull request builder output.
Worked on making changes to the permissiondenied error.
Fixed typo
Signed-off-by: Sean Rodman <srodman7689@gmail.com>
Updated error message as requested.
Fixed the error as requested
Signed-off-by: Sean Rodman <srodman7689@gmail.com>
Under the convoluted code path for the transport configuration,
TLSConfig was being set even though the socket type is unix. This caused
other code detecting the TLSConfig to assume https, rather than using
the http scheme. This led to a situation where if `DOCKER_CERT_PATH` is
set, unix sockets start reverting to https. There is other odd behavior
from go-connections that is also reproduced here.
For the most part, we try to reproduce the side-effecting behavior from
go-connections to retain the current docker behavior. This whole mess
needs to ripped out and fixed, as this pile spaghetti is unnacceptable.
This code is way to convoluted for an http client. We'll need to fix
this but the Go API will break to do it.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This package doesn't really seem to do anything of real interest.
Removing it and replacing with a few helper functions. Most of this was
maintaining a fork of ctxhttp to support a mock that was unnecessary.
We could probably do with a further refactor of the client interface.
There is a lot of confusion of between transport, http layer and
application layer that makes for some awkward code. This change
improves the situation to the point where no breaking changes are
introduced.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Instead of reformatting error from the request action, we wrap it,
allowing the cause to be recovered. This is important for consumers that
need to be able to detect context errors, such as `Cancelled` and
`DeadlineExceeded`.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
