6aea26b431
Commit e6907243af applied a fix for situations
where the client was configured with API-version negotiation, but did not yet
negotiate a version.
However, the checkVersion() function that was implemented copied the semantics
of cli.NegotiateAPIVersion, which ignored connection failures with the
assumption that connection errors would still surface further down.
However, when using the result of a failed negotiation for NewVersionError,
an API version mismatch error would be produced, masking the actual connection
error.
This patch changes the signature of checkVersion to return unexpected errors,
including failures to connect to the API.
Before this patch:
docker -H unix:///no/such/socket.sock secret ls
"secret list" requires API version 1.25, but the Docker daemon API version is 1.24
With this patch applied:
docker -H unix:///no/such/socket.sock secret ls
Cannot connect to the Docker daemon at unix:///no/such/socket.sock. Is the docker daemon running?
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
117 lines
3.6 KiB
Go
117 lines
3.6 KiB
Go
package client // import "github.com/docker/docker/client"
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"io"
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"net/url"
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"github.com/docker/docker/api/types/container"
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"github.com/docker/docker/api/types/versions"
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)
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const containerWaitErrorMsgLimit = 2 * 1024 /* Max: 2KiB */
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// ContainerWait waits until the specified container is in a certain state
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// indicated by the given condition, either "not-running" (default),
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// "next-exit", or "removed".
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//
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// If this client's API version is before 1.30, condition is ignored and
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// ContainerWait will return immediately with the two channels, as the server
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// will wait as if the condition were "not-running".
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//
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// If this client's API version is at least 1.30, ContainerWait blocks until
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// the request has been acknowledged by the server (with a response header),
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// then returns two channels on which the caller can wait for the exit status
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// of the container or an error if there was a problem either beginning the
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// wait request or in getting the response. This allows the caller to
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// synchronize ContainerWait with other calls, such as specifying a
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// "next-exit" condition before issuing a ContainerStart request.
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func (cli *Client) ContainerWait(ctx context.Context, containerID string, condition container.WaitCondition) (<-chan container.WaitResponse, <-chan error) {
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resultC := make(chan container.WaitResponse)
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errC := make(chan error, 1)
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// Make sure we negotiated (if the client is configured to do so),
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// as code below contains API-version specific handling of options.
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//
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// Normally, version-negotiation (if enabled) would not happen until
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// the API request is made.
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if err := cli.checkVersion(ctx); err != nil {
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errC <- err
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return resultC, errC
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}
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if versions.LessThan(cli.ClientVersion(), "1.30") {
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return cli.legacyContainerWait(ctx, containerID)
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}
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query := url.Values{}
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if condition != "" {
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query.Set("condition", string(condition))
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}
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resp, err := cli.post(ctx, "/containers/"+containerID+"/wait", query, nil, nil)
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if err != nil {
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defer ensureReaderClosed(resp)
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errC <- err
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return resultC, errC
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}
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go func() {
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defer ensureReaderClosed(resp)
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body := resp.body
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responseText := bytes.NewBuffer(nil)
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stream := io.TeeReader(body, responseText)
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var res container.WaitResponse
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if err := json.NewDecoder(stream).Decode(&res); err != nil {
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// NOTE(nicks): The /wait API does not work well with HTTP proxies.
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// At any time, the proxy could cut off the response stream.
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//
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// But because the HTTP status has already been written, the proxy's
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// only option is to write a plaintext error message.
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//
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// If there's a JSON parsing error, read the real error message
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// off the body and send it to the client.
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if errors.As(err, new(*json.SyntaxError)) {
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_, _ = io.ReadAll(io.LimitReader(stream, containerWaitErrorMsgLimit))
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errC <- errors.New(responseText.String())
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} else {
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errC <- err
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}
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return
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}
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resultC <- res
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}()
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return resultC, errC
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}
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// legacyContainerWait returns immediately and doesn't have an option to wait
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// until the container is removed.
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func (cli *Client) legacyContainerWait(ctx context.Context, containerID string) (<-chan container.WaitResponse, <-chan error) {
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resultC := make(chan container.WaitResponse)
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errC := make(chan error)
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go func() {
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resp, err := cli.post(ctx, "/containers/"+containerID+"/wait", nil, nil, nil)
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if err != nil {
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errC <- err
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return
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}
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defer ensureReaderClosed(resp)
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var res container.WaitResponse
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if err := json.NewDecoder(resp.body).Decode(&res); err != nil {
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errC <- err
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return
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}
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resultC <- res
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}()
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return resultC, errC
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}
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