open-nomad/client/allocrunner/taskrunner/dispatch_hook.go
2023-04-10 15:36:59 +00:00

76 lines
1.8 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package taskrunner
import (
"context"
"os"
"path/filepath"
"github.com/golang/snappy"
hclog "github.com/hashicorp/go-hclog"
"github.com/hashicorp/nomad/client/allocrunner/interfaces"
"github.com/hashicorp/nomad/nomad/structs"
)
// dispatchHook writes a dispatch payload to the task dir
type dispatchHook struct {
payload []byte
logger hclog.Logger
}
func newDispatchHook(alloc *structs.Allocation, logger hclog.Logger) *dispatchHook {
h := &dispatchHook{
payload: alloc.Job.Payload,
}
h.logger = logger.Named(h.Name())
return h
}
func (*dispatchHook) Name() string {
// Copied in client/state when upgrading from <0.9 schemas, so if you
// change it here you also must change it there.
return "dispatch_payload"
}
func (h *dispatchHook) Prestart(ctx context.Context, req *interfaces.TaskPrestartRequest, resp *interfaces.TaskPrestartResponse) error {
if len(h.payload) == 0 || req.Task.DispatchPayload == nil || req.Task.DispatchPayload.File == "" {
// No dispatch payload
resp.Done = true
return nil
}
err := writeDispatchPayload(req.TaskDir.LocalDir, req.Task.DispatchPayload.File, h.payload)
if err != nil {
return err
}
h.logger.Trace("dispatch payload written",
"path", req.TaskDir.LocalDir,
"filename", req.Task.DispatchPayload.File,
"bytes", len(h.payload),
)
// Dispatch payload written successfully; mark as done
resp.Done = true
return nil
}
// writeDispatchPayload writes the payload to the given file or returns an
// error.
func writeDispatchPayload(base, filename string, payload []byte) error {
renderTo := filepath.Join(base, filename)
decoded, err := snappy.Decode(nil, payload)
if err != nil {
return err
}
if err := os.MkdirAll(filepath.Dir(renderTo), 0777); err != nil {
return err
}
return os.WriteFile(renderTo, decoded, 0777)
}