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"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/pkg/archive"
)
// 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 09:48:13 +00:00
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) (container.ContainerCreateCreatedBody, 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, checkpoint string, checkpointDir string) error
ContainerStop(name string, seconds *int) error
ContainerUnpause(name string) error
ContainerUpdate(name string, hostConfig *container.HostConfig) (container.ContainerUpdateOKBody, 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
}
// systemBackend includes functions to implement to provide system wide containers functionality
type systemBackend interface {
ContainersPrune(config *types.ContainersPruneConfig) (*types.ContainersPruneReport, error)
}
// Backend is all the methods that need to be implemented to provide container specific functionality.
type Backend interface {
execBackend
copyBackend
stateBackend
monitorBackend
attachBackend
systemBackend
}