flamenco/internal/worker/task_executor.go
Sybren A. Stüvel 62ea7dcf1d Worker: avoid task errors on shutdown
When shutting down, the main worker context closes. This causes the
subprocess to be killed, which in turn caused a task execution error. This
now no longer happens, as such errors are expected on shutdown and do not
indicate task failure.
2022-04-08 14:32:25 +02:00

100 lines
2.8 KiB
Go

package worker
// SPDX-License-Identifier: GPL-3.0-or-later
import (
"context"
"errors"
"fmt"
"github.com/rs/zerolog/log"
"git.blender.org/flamenco/pkg/api"
)
type CommandRunner interface {
Run(ctx context.Context, taskID string, cmd api.Command) error
}
// Generate mock implementation of this interface.
//go:generate go run github.com/golang/mock/mockgen -destination mocks/task_exe_listener.gen.go -package mocks git.blender.org/flamenco/internal/worker TaskExecutionListener
// TaskExecutionListener sends task lifecycle events (start/fail/complete) to the Manager.
type TaskExecutionListener interface {
// TaskStarted tells the Manager that task execution has started.
TaskStarted(ctx context.Context, taskID string) error
// TaskFailed tells the Manager the task failed for some reason.
TaskFailed(ctx context.Context, taskID string, reason string) error
// TaskCompleted tells the Manager the task has been completed.
TaskCompleted(ctx context.Context, taskID string) error
}
type TaskExecutor struct {
cmdRunner CommandRunner
listener TaskExecutionListener
}
var _ TaskRunner = (*TaskExecutor)(nil)
func NewTaskExecutor(cmdRunner CommandRunner, listener TaskExecutionListener) *TaskExecutor {
return &TaskExecutor{
cmdRunner: cmdRunner,
listener: listener,
}
}
// Run runs a task.
// Returns ErrTaskReassigned when the task was reassigned to another worker.
func (te *TaskExecutor) Run(ctx context.Context, task api.AssignedTask) error {
logger := log.With().Str("task", task.Uuid).Logger()
logger.Info().Str("taskType", task.TaskType).Msg("starting task")
if err := te.listener.TaskStarted(ctx, task.Uuid); err != nil {
if err == ErrTaskReassigned {
return ErrTaskReassigned
}
return fmt.Errorf("sending 'task started' notification to manager: %w", err)
}
for _, cmd := range task.Commands {
select {
case <-ctx.Done():
// Shutdown does not mean task failure; cleanly shutting down will hand
// back the task for requeueing on the Manager.
logger.Warn().Msg("task execution aborted due to context shutdown")
return nil
default:
}
runErr := te.cmdRunner.Run(ctx, task.Uuid, cmd)
if runErr == nil {
// All was fine, go run the next command.
continue
}
if errors.Is(runErr, context.Canceled) {
logger.Warn().Msg("task execution aborted due to context shutdown")
return nil
}
// Notify Manager that this task failed.
if err := te.listener.TaskFailed(ctx, task.Uuid, runErr.Error()); err != nil {
if err == ErrTaskReassigned {
return ErrTaskReassigned
}
return fmt.Errorf("sending 'task failed' notification to manager: %w", err)
}
return runErr
}
if err := te.listener.TaskCompleted(ctx, task.Uuid); err != nil {
if err == ErrTaskReassigned {
return ErrTaskReassigned
}
return fmt.Errorf("sending 'task completed' notification to manager: %w", err)
}
return nil
}