uncloud/internal/service/container.go

package service

import (
	"github.com/docker/docker/api/types"
	"regexp"
)

const (
	LabelServiceID   = "uncloud.service.id"
	LabelServiceName = "uncloud.service.name"
	LabelServiceMode = "uncloud.service.mode"
)

type Container struct {
	types.Container
}

// ServiceID returns the service ID that the container is part of.
func (c *Container) ServiceID() string {
	return c.Labels[LabelServiceID]
}

// ServiceName returns the service name that the container is part of.
func (c *Container) ServiceName() string {
	return c.Labels[LabelServiceName]
}

// ServiceMode returns the replication mode of the service that the container is part of.
func (c *Container) ServiceMode() string {
	return c.Labels[LabelServiceMode]
}

// runningStatusRegex matches the status string of a running container.
// - "Up 3 minutes (healthy)" -> groups: ["Up 3 minutes (healthy)", "healthy"]
// - "Up 5 seconds" -> groups: ["Up 5 seconds", ""]
// - "Up 2 hours (unhealthy)" -> groups: ["Up 2 hours (unhealthy)", "unhealthy"]
// - "Up 1 minute (health: starting)" -> groups: ["Up 1 minute (health: starting)", "health: starting"]
// - "Restarting (0) 5 seconds ago" -> no match
// See https://github.com/moby/moby/blob/c130ce1f5d1e38b98a97044a39557de43bc0d58f/container/state.go#L77-L90
// for more details on how the status string for a running container is formatted.
var runningStatusRegex = regexp.MustCompile(`^Up [^(]+(?:\(([^)]+)\))?$`)

// Healthy determines if the container is running and healthy based on its status string.
// A running container with no health check configured is considered healthy.
func (c *Container) Healthy() bool {
	if c.State != "running" {
		return false
	}

	matches := runningStatusRegex.FindStringSubmatch(c.Status)
	// Not "Up" or invalid format.
	if matches == nil {
		return false
	}

	// If there's no health status (no health check configured so no parentheses), container is considered healthy.
	if matches[1] == "" {
		return true
	}

	// If the health status in parentheses is "healthy", the container is considered healthy.
	return matches[1] == types.Healthy
}