76 lines
2.0 KiB
Go
76 lines
2.0 KiB
Go
// Package controller composes independently runnable scheduler and backend workers.
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package controller
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import (
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"context"
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"errors"
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"fmt"
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"slices"
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"strings"
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"golang.org/x/sync/errgroup"
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)
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type ComponentName string
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const (
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Scheduler ComponentName = "scheduler"
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PodWorker ComponentName = "pod-worker"
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VMWorker ComponentName = "vm-worker"
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)
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var defaultComponents = []ComponentName{Scheduler, PodWorker, VMWorker}
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// Selection parses --components. An empty value enables all components.
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type Selection []ComponentName
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func ParseSelection(value string) (Selection, error) {
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if strings.TrimSpace(value) == "" || strings.TrimSpace(value) == "all" {
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return append(Selection(nil), defaultComponents...), nil
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}
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var selected Selection
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for _, raw := range strings.Split(value, ",") {
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name := ComponentName(strings.TrimSpace(raw))
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if !slices.Contains(defaultComponents, name) {
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return nil, fmt.Errorf("unknown controller component %q", name)
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}
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if !slices.Contains(selected, name) {
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selected = append(selected, name)
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}
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}
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if len(selected) == 0 {
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return nil, errors.New("at least one controller component is required")
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}
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return selected, nil
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}
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type Component interface {
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Run(context.Context) error
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}
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type Registry map[ComponentName]Component
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// Run starts exactly the selected components in one process. The first real
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// failure cancels its peers; ordinary context cancellation is graceful.
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func Run(ctx context.Context, selection Selection, registry Registry) error {
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group, groupContext := errgroup.WithContext(ctx)
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for _, name := range selection {
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component, ok := registry[name]
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if !ok || component == nil {
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return fmt.Errorf("component %q is not configured", name)
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}
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name, component := name, component
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group.Go(func() error {
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err := component.Run(groupContext)
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if errors.Is(err, context.Canceled) && groupContext.Err() != nil {
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return nil
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}
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if err != nil {
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return fmt.Errorf("component %s: %w", name, err)
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}
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return nil
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})
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}
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return group.Wait()
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}
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