This introduces a `WithMinimumAPIVersion` RouteWrapper to configure the
minimum API version required for a route. It produces a 400 (Invalid Request)
error when accessing the endpoint on API versions lower than the given version.
Note that technically, it should produce a 404 ("not found") error,
as the endpoint should be considered "non-existing" on such API versions,
but 404 status-codes are used in business logic for various endpoints.
This patch allows removal of corresponding API-version checks from the client,
and other implementation of clients for the API. While the produced error message
is slightly more "technical", these situations should be rare and only happen
when the API version of the client is explicitly overridden, or a client was
implemented with a fixed API version (potentially missing version checks).
Before this patch, these errors were produced by the client:
DOCKER_API_VERSION=v1.24 docker container prune -f
docker container prune requires API version 1.25, but the Docker daemon API version is 1.24
With this patch applied, the error is returned by the daemon:
DOCKER_API_VERSION=v1.24 docker container prune -f
Error response from daemon: POST /containers/prune requires minimum API version 1.25
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
These comments were added to enforce using the correct import path for
our packages ("github.com/docker/docker", not "github.com/moby/moby").
However, when working in go module mode (not GOPATH / vendor), they have
no effect, so their impact is limited.
Remove these imports in preparation of migrating our code to become an
actual go module.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Looking in history to learn why this struct existed, shows that this type
was mostly the result of tech-debt accumulating over time;
- originally ([moby@1aa7f13]) most of the request handling was internal;
the [`call()` function][1] would make a request, read the `response.Body`,
and return it as a `[]byte` (or an error if one happened).
- some features needed the statuscode, so [moby@a4bcf7e] added an extra
output variable to return the `response.StatusCode`.
- some new features required streaming, so [moby@fdd8d4b] changed the
function to return the `response.Body` as a `io.ReadCloser`, instead
of a `[]byte`.
- some features needed access to the content-type header, so a new
`clientRequest` method was introduced in [moby@6b2eeaf] to read the
`Content-Type` header from `response.Headers` and return it as a string.
- of course, `Content-Type` may not be the only header needed, so [moby@0cdc3b7]
changed the signature to return `response.Headers` as a whole as a
`http.Header`
- things became a bit unwieldy now, with the function having four (4) output
variables, so [moby@126529c] chose to refactor this code, introducing a
`serverResponse` struct to wrap them all, not realizing that all these
values were effectively deconstructed from the `url.Response`, so now
re-assembling them into our own "URL response", only preserving a subset
of the information available.
- now that we had a custom struct, it was possible to add more information
to it without changing the signature. When there was a need to know the
URL of the request that initiated the response, [moby@27ef09a] introduced
a `reqURL` field to hold the `request.URL` which notably also is available
in `response.Request.URL`.
In short;
- The original implementation tried to (pre-maturely) abstract the underlying
response to provide a simplified interface.
- While initially not needed, abstracting caused relevant information from
the response (and request) to be unavailable to callers.
- As a result, we ended up in a situation where we are deconstructing the
original `url.Response`, only to re-assemble it into our own, custom struct
(`serverResponsee`) with only a subset of the information preserved.
This patch removes the `serverResponse` struct, instead returning the
`url.Response` as-is, so that all information is preserved, allowing callers
to use the information they need.
There is one follow-up change to consider; commit [moby@589df17] introduced
a `ensureReaderClosed` utility. Before that commit, the response body would
be closed in a more idiomatic way through a [`defer serverResp.body.Close()`][2].
A later change in [docker/engine-api@5dd6452] added an optimization to that
utility, draining the response to allow connections to be reused. While
skipping that utility (and not draining the response) would not be a critical
issue, it may be easy to overlook that utility, and to close the response
body in the "idiomatic" way, resulting in a possible performance regression.
We need to check if that optimization is still relevant or if later changes
in Go itself already take care of this; we should also look if context
cancellation is handled correctly for these. If it's still relevant, we could
- Wrap the the `url.Response` in a custom struct ("drainCloser") to provide
a `Close()` function handling the draining and closing; this would re-
introduce a custom type to be returned, so perhaps not what we want.
- Wrap the `url.Response.Body` in the response returned (so, calling)
`response.Body.Close()` would call the wrapped closer.
- Change the signature of `Client.sendRequest()` (and related) to return
a `close()` func to handle this; doing so would more strongly encourage
callers to close the response body.
[1]: 1aa7f1392d/commands.go (L1008-L1027)
[2]: 589df17a1a/api/client/ps.go (L84-L89)
[moby@1aa7f13]: 1aa7f1392d
[moby@a4bcf7e]: a4bcf7e1ac
[moby@fdd8d4b]: fdd8d4b7d9
[moby@6b2eeaf]: 6b2eeaf896
[moby@0cdc3b7]: 0cdc3b7539
[moby@126529c]: 126529c6d0
[moby@27ef09a]: 27ef09a46f
[moby@589df17]: 589df17a1a
[docker/engine-api@5dd6452]: 5dd6452d4d
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
We try to perform API-version negotiation as lazy as possible (and only execute
when we are about to make an API request). However, some code requires API-version
dependent handling (to set options, or remove options based on the version of the
API we're using).
Currently this code depended on the caller code to perform API negotiation (or
to configure the API version) first, which may not happen, and because of that
we may be missing options (or set options that are not supported on older API
versions).
This patch:
- splits the code that triggered API-version negotiation to a separate
Client.checkVersion() function.
- updates NewVersionError to accept a context
- updates NewVersionError to perform API-version negotiation (if enabled)
- updates various Client functions to manually trigger API-version negotiation
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Changes certain words and adds punctuation to the comments of functions in the client package, which end up in the GoDoc documentation. Areas where only periods were needed were ignored to prevent excessive code churn.
Signed-off-by: Levi Harrison <levisamuelharrison@gmail.com>
Unlike a plain `net/http/client.Do()`, requests made through client/request
use the `sendRequest` function, which parses the server response, and may
convert non-transport errors into errors (through `cli.checkResponseErr()`).
This means that we cannot assume that no reader was opened if an error is
returned.
This patch changes various locations where `ensureReaderClosed` was only
called in the non-error situation, and uses a `defer` to make sure it's
always called.
`ensureReaderClosed` itself already checks if the response's body was set,
so in situations where the error was due to a transport error, calling
`ensureReaderClosed` should be a no-op.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
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>
The Docker CLI already performs version-checks when
running commands, but other clients consuming the API
client may not do so.
This patch adds a version check to various
client functions.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
