Files

57 lines
1.8 KiB
Go

// Package selfupdate handles the special case where the update target
// is the running service's own container. We must finish writing the
// HTTP response (and flush + close the connection) before exec'ing
// `docker compose up -d` against ourselves, otherwise the response is
// lost when the container is replaced.
package selfupdate
import (
"context"
"time"
"github.com/shcizo/package-updater/internal/discovery"
)
// IsSelf reports whether job targets the running service.
// Matches on Compose project name (which is also typically the
// service name for single-service stacks).
func IsSelf(job discovery.Job, selfProject string) bool {
return job.Project == selfProject
}
// innerExec is the executor abstraction we wrap.
type innerExec interface {
Execute(ctx context.Context, job discovery.Job) error
}
// Wrapped wraps an Executor with self-update-aware deferred execution.
type Wrapped struct {
inner innerExec
selfProject string
delay time.Duration
}
// Wrap returns a Wrapped that defers exec until after flush() for
// self-updates. The delay is added after flush before exec, so the
// kernel TCP buffer has time to drain.
func Wrap(inner innerExec, selfProject string, delay time.Duration) *Wrapped {
return &Wrapped{inner: inner, selfProject: selfProject, delay: delay}
}
// ExecuteWithFlush runs job, invoking flush() before exec for self-updates
// and waiting `delay` after flush. For non-self jobs, exec happens
// normally and flush is not invoked at all (the HTTP layer decides
// when to flush in that case).
func (w *Wrapped) ExecuteWithFlush(ctx context.Context, job discovery.Job, flush func()) error {
if !IsSelf(job, w.selfProject) {
return w.inner.Execute(ctx, job)
}
flush()
select {
case <-time.After(w.delay):
case <-ctx.Done():
return ctx.Err()
}
return w.inner.Execute(ctx, job)
}