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moby--moby/api/server/router/container/backend.go

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package container
import (
"io"
"time"
"golang.org/x/net/context"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/pkg/archive"
"github.com/docker/engine-api/types"
"github.com/docker/engine-api/types/container"
)
// execBackend includes functions to implement to provide exec functionality.
type execBackend interface {
ContainerExecCreate(name string, config *types.ExecConfig) (string, error)
ContainerExecInspect(id string) (*backend.ExecInspect, error)
ContainerExecResize(name string, height, width int) error
Add support for user-defined healthchecks This PR adds support for user-defined health-check probes for Docker containers. It adds a `HEALTHCHECK` instruction to the Dockerfile syntax plus some corresponding "docker run" options. It can be used with a restart policy to automatically restart a container if the check fails. The `HEALTHCHECK` instruction has two forms: * `HEALTHCHECK [OPTIONS] CMD command` (check container health by running a command inside the container) * `HEALTHCHECK NONE` (disable any healthcheck inherited from the base image) The `HEALTHCHECK` instruction tells Docker how to test a container to check that it is still working. This can detect cases such as a web server that is stuck in an infinite loop and unable to handle new connections, even though the server process is still running. When a container has a healthcheck specified, it has a _health status_ in addition to its normal status. This status is initially `starting`. Whenever a health check passes, it becomes `healthy` (whatever state it was previously in). After a certain number of consecutive failures, it becomes `unhealthy`. The options that can appear before `CMD` are: * `--interval=DURATION` (default: `30s`) * `--timeout=DURATION` (default: `30s`) * `--retries=N` (default: `1`) The health check will first run **interval** seconds after the container is started, and then again **interval** seconds after each previous check completes. If a single run of the check takes longer than **timeout** seconds then the check is considered to have failed. It takes **retries** consecutive failures of the health check for the container to be considered `unhealthy`. There can only be one `HEALTHCHECK` instruction in a Dockerfile. If you list more than one then only the last `HEALTHCHECK` will take effect. The command after the `CMD` keyword can be either a shell command (e.g. `HEALTHCHECK CMD /bin/check-running`) or an _exec_ array (as with other Dockerfile commands; see e.g. `ENTRYPOINT` for details). The command's exit status indicates the health status of the container. The possible values are: - 0: success - the container is healthy and ready for use - 1: unhealthy - the container is not working correctly - 2: starting - the container is not ready for use yet, but is working correctly If the probe returns 2 ("starting") when the container has already moved out of the "starting" state then it is treated as "unhealthy" instead. For example, to check every five minutes or so that a web-server is able to serve the site's main page within three seconds: HEALTHCHECK --interval=5m --timeout=3s \ CMD curl -f http://localhost/ || exit 1 To help debug failing probes, any output text (UTF-8 encoded) that the command writes on stdout or stderr will be stored in the health status and can be queried with `docker inspect`. Such output should be kept short (only the first 4096 bytes are stored currently). When the health status of a container changes, a `health_status` event is generated with the new status. The health status is also displayed in the `docker ps` output. Signed-off-by: Thomas Leonard <thomas.leonard@docker.com> Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2016-04-18 05:48:13 -04:00
ContainerExecStart(ctx context.Context, name string, stdin io.ReadCloser, stdout io.Writer, stderr io.Writer) error
ExecExists(name string) (bool, error)
}
// copyBackend includes functions to implement to provide container copy functionality.
type copyBackend interface {
ContainerArchivePath(name string, path string) (content io.ReadCloser, stat *types.ContainerPathStat, err error)
ContainerCopy(name string, res string) (io.ReadCloser, error)
ContainerExport(name string, out io.Writer) error
ContainerExtractToDir(name, path string, noOverwriteDirNonDir bool, content io.Reader) error
ContainerStatPath(name string, path string) (stat *types.ContainerPathStat, err error)
}
// stateBackend includes functions to implement to provide container state lifecycle functionality.
type stateBackend interface {
ContainerCreate(config types.ContainerCreateConfig, validateHostname bool) (types.ContainerCreateResponse, error)
ContainerKill(name string, sig uint64) error
ContainerPause(name string) error
ContainerRename(oldName, newName string) error
ContainerResize(name string, height, width int) error
ContainerRestart(name string, seconds int) error
ContainerRm(name string, config *types.ContainerRmConfig) error
ContainerStart(name string, hostConfig *container.HostConfig, validateHostname bool) error
ContainerStop(name string, seconds int) error
ContainerUnpause(name string) error
ContainerUpdate(name string, hostConfig *container.HostConfig, validateHostname bool) ([]string, error)
ContainerWait(name string, timeout time.Duration) (int, error)
}
// monitorBackend includes functions to implement to provide containers monitoring functionality.
type monitorBackend interface {
ContainerChanges(name string) ([]archive.Change, error)
ContainerInspect(name string, size bool, version string) (interface{}, error)
ContainerLogs(ctx context.Context, name string, config *backend.ContainerLogsConfig, started chan struct{}) error
ContainerStats(ctx context.Context, name string, config *backend.ContainerStatsConfig) error
ContainerTop(name string, psArgs string) (*types.ContainerProcessList, error)
Containers(config *types.ContainerListOptions) ([]*types.Container, error)
}
// attachBackend includes function to implement to provide container attaching functionality.
type attachBackend interface {
ContainerAttach(name string, c *backend.ContainerAttachConfig) error
}
// Backend is all the methods that need to be implemented to provide container specific functionality.
type Backend interface {
execBackend
copyBackend
stateBackend
monitorBackend
attachBackend
}