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 API now includes this information per record, and clients can
get this information using the `Ping` method if needed as fallback.
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>
This utility was added in 83b5729f64 to
replace httputils.ParseServerHeader, which was added to print a warning
on Windows in 126529c6d0. At the time, the
only available option to detect the daemon's OS was to parse the `Server`
header, which contained the version of Docker as well as the OS.
However, 7199522ea2 introduced an `OSType`
("Ostype") header that's included on all responses, and a later commit
e9dac5ef5e changed that to also be included
when producing an error for unsupported API versions.
Note that the casing in the midddleware was changed from `OSType` to
`Ostype` (normalized form) in 76a5ca1d4d,
but headers are case-insensitive, and `header.Get()` should handle either
case in the response.
In short; every API response contains an "Ostype" header, which already
contains the OS ("windows" or "linux") that doesn't require any parsing,
so let's put that header to use.
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>
In situations where an empty ID was passed, the client would construct an
invalid API endpoint URL, which either resulted in the "not found" handler
being hit (resulting in a "page not found" error), or even the wrong endpoint
being hit if the client follows redirects.
For example, `/containers/<empty id>/json` (inspect) redirects to `/containers/json`
(docker ps))
Given that empty IDs should never be expected (especially if they're part of
the API URL path), we can validate these and return early.
Its worth noting that a few methods already had an error in place; those
methods were related to the situation mentioned above, where (e.g.) an
"inspect" would redirect to a "list" endpoint. The existing errors, for
convenience, mimicked a "not found" error; this patch changes such errors
to an "Invalid Parameter" instead, which is more correct, but it could be
a breaking change for some edge cases where users parsed the output;
git grep 'objectNotFoundError{'
client/config_inspect.go: return swarm.Config{}, nil, objectNotFoundError{object: "config", id: id}
client/container_inspect.go: return container.InspectResponse{}, nil, objectNotFoundError{object: "container", id: containerID}
client/container_inspect.go: return container.InspectResponse{}, objectNotFoundError{object: "container", id: containerID}
client/distribution_inspect.go: return distributionInspect, objectNotFoundError{object: "distribution", id: imageRef}
client/image_inspect.go: return image.InspectResponse{}, nil, objectNotFoundError{object: "image", id: imageID}
client/network_inspect.go: return network.Inspect{}, nil, objectNotFoundError{object: "network", id: networkID}
client/node_inspect.go: return swarm.Node{}, nil, objectNotFoundError{object: "node", id: nodeID}
client/plugin_inspect.go: return nil, nil, objectNotFoundError{object: "plugin", id: name}
client/secret_inspect.go: return swarm.Secret{}, nil, objectNotFoundError{object: "secret", id: id}
client/service_inspect.go: return swarm.Service{}, nil, objectNotFoundError{object: "service", id: serviceID}
client/task_inspect.go: return swarm.Task{}, nil, objectNotFoundError{object: "task", id: taskID}
client/volume_inspect.go: return volume.Volume{}, nil, objectNotFoundError{object: "volume", id: volumeID}
Two such errors are still left, as "ID or name" would probably be confusing,
but perhaps we can use a more generic error to include those as well (e.g.
"invalid <object> reference: value is empty");
client/distribution_inspect.go: return distributionInspect, objectNotFoundError{object: "distribution", id: imageRef}
client/image_inspect.go: return image.InspectResponse{}, nil, objectNotFoundError{object: "image", id: imageID}
Before this patch:
docker container start ""
Error response from daemon: page not found
Error: failed to start containers:
docker container start " "
Error response from daemon: No such container:
Error: failed to start containers:
With this patch:
docker container start ""
invalid container name or ID: value is empty
Error: failed to start containers:
docker container start " "
invalid container name or ID: value is empty
Error: failed to start containers:
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
commit 17c3269a37 moved the ContainerStats
type to the container package, and renamed it to StatsResponse. However,
this name is chosen poorly, as it documents it to be the response of
the API endpoint, but is more accurately a wrapper around a reader,
used to read a (stream of) StatsJSON. We want to change StatsJSON
to StatsResponse, as it's more consistent with other response types.
As 17c3269a37 did not make it into a
non-pre-release, we can still change this.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This is the response type; other types related to stats are left
for now, but should be moved (as well as utilities ported from
the CLI repository).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
- remove some intermediate variables
- explicitly return "nil" if there's no error
- remove redundant check for response-headers being nil
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Metrics collectors generally don't need the daemon to prime the stats
with something to compare since they already have something to compare
with.
Before this change, the API does 2 collection cycles (which takes
roughly 2s) in order to provide comparison for CPU usage over 1s. This
was primarily added so that `docker stats --no-stream` had something to
compare against.
Really the CLI should have just made a 2nd call and done the comparison
itself rather than forcing it on all API consumers.
That ship has long sailed, though.
With this change, clients can set an option to just pull a single stat,
which is *at least* a full second faster:
Old:
```
time curl --unix-socket
/go/src/github.com/docker/docker/bundles/test-integration-shell/docker.sock
http://./containers/test/stats?stream=false\&one-shot=false > /dev/null
2>&1
real0m1.864s
user0m0.005s
sys0m0.007s
time curl --unix-socket
/go/src/github.com/docker/docker/bundles/test-integration-shell/docker.sock
http://./containers/test/stats?stream=false\&one-shot=false > /dev/null
2>&1
real0m1.173s
user0m0.010s
sys0m0.006s
```
New:
```
time curl --unix-socket
/go/src/github.com/docker/docker/bundles/test-integration-shell/docker.sock
http://./containers/test/stats?stream=false\&one-shot=true > /dev/null
2>&1
real0m0.680s
user0m0.008s
sys0m0.004s
time curl --unix-socket
/go/src/github.com/docker/docker/bundles/test-integration-shell/docker.sock
http://./containers/test/stats?stream=false\&one-shot=true > /dev/null
2>&1
real0m0.156s
user0m0.007s
sys0m0.007s
```
This fixes issues with downstreams ability to use the stats API to
collect metrics.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
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>
