Use a cancelReadCloser to automatically close the reader when the context
is cancelled. Consumers are still recommended to manually close the reader,
but the cancelReadCloser makes the Close idempotent.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The JSON field was added in [moby@9fd2c0f], to address [moby#19177], which
reported an incompatibility with Classic (V1) Swarm, which produced a non-
standard response;
> Make docker load to output json when the response content type is json
> Swarm hijacks the response from docker load and returns JSON rather
> than plain text like the Engine does. This makes the API library to return
> information to figure that out.
A later change in [moby@96d7db6] added additional logic to make sure the
correct content-type was returned, depending on whether the `quiet` option
was set (which produced a non-JSON response). This caused inconsistency in
the API response, and [moby@2f27632] changed the endpoint to always produce
JSON (only skipping the "progress" output if `quiet` was set).
This means that the "load" endpoint ([`imageRouter.postImagesLoad`]) now
unconditionally returns JSON, making the `JSON` field fully redundant.
We should consider deprecating the "quiet" option, as it's really the client's
responsibility to show or hide progress-bars, but we can do this separately.
This patch removes the JSON field, as it's redundant, and the way it handles
the content-type is incorrect because it would not handle correct, but different
formatted response-headers (`application/json; charset=utf-8`), which could
result in malformed output on the client.
[moby@9fd2c0f]: 9fd2c0feb0
[moby#19177]: https://github.com/moby/moby/issues/19177
[moby@96d7db6]: 96d7db665b
[moby@2f27632]: 2f27632cde
[`imageRouter.postImagesLoad`]: 7b9d2ef6e5/api/server/router/image/image_routes.go (L248-L255)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
It's not the response coming from the API, but a wrapper for a response
reader. We should ultimately remove it.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Not perfect yet, but addressing some godoc "doc" links that needed
to be updated, and touching up some references.
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 don't yet support this at the API level, so for now it returns
an error when trying to set multiple, but this makes sure that the
client types are already ready for this.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add `Platform` parameter that allows to select a specific platform to
save/load.
This is a breaking change to the Go client as it changes the signatures
of `ImageLoad` and `ImageSave`.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
This moves the type, but we should consider removing this type, and just
returning an io.ReadCloser
This type was added in 9fd2c0feb0c131d01d727d50baa7183b976c7bdc;
> Make docker load to output json when the response content type is json
> Swarm hijacks the response from docker load and returns JSON rather
> than plain text like the Engine does. This makes the API library to return
> information to figure that out.
However the "load" endpoint unconditionally returns JSON;
7b9d2ef6e5/api/server/router/image/image_routes.go (L248-L255)
Commit 96d7db665b made the response-type depend
on whether "quiet" was set, but this logic got changed in a follow-up
2f27632cde, which made the JSON response-type
unconditionally, but the output produced depend on whether"quiet" was set.
We should deprecated the "quiet" option, as it's really a client
responsibility.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Use http.Header, which is more descriptive on intent, and we're already
importing the package in the client. Removing the "header" type also fixes
various locations where the type was shadowed by local variables named
"headers".
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>
