ce1ceeb257
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>
42 lines
1.3 KiB
Go
42 lines
1.3 KiB
Go
package client // import "github.com/docker/docker/client"
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import (
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"context"
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"net/url"
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"github.com/docker/docker/api/types"
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)
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// ContainerStats returns near realtime stats for a given container.
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// It's up to the caller to close the io.ReadCloser returned.
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func (cli *Client) ContainerStats(ctx context.Context, containerID string, stream bool) (types.ContainerStats, error) {
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query := url.Values{}
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query.Set("stream", "0")
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if stream {
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query.Set("stream", "1")
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}
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resp, err := cli.get(ctx, "/containers/"+containerID+"/stats", query, nil)
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if err != nil {
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return types.ContainerStats{}, err
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}
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osType := getDockerOS(resp.header.Get("Server"))
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return types.ContainerStats{Body: resp.body, OSType: osType}, err
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}
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// ContainerStatsOneShot gets a single stat entry from a container.
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// It differs from `ContainerStats` in that the API should not wait to prime the stats
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func (cli *Client) ContainerStatsOneShot(ctx context.Context, containerID string) (types.ContainerStats, error) {
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query := url.Values{}
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query.Set("stream", "0")
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query.Set("one-shot", "1")
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resp, err := cli.get(ctx, "/containers/"+containerID+"/stats", query, nil)
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if err != nil {
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return types.ContainerStats{}, err
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}
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osType := getDockerOS(resp.header.Get("Server"))
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return types.ContainerStats{Body: resp.body, OSType: osType}, err
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}
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