Fix task is not properly restarted when the live is closed and started again.

Use more friendly log format to replace golang's default `log.Logger`. (not completed)
Cleaner task status management.

1 files changed, 87 insertions, 0 deletions

diff --git a/recording/task.go b/recording/task.go
new file mode 100644
index 0000000..9aa41a8
--- /dev/null
+++ b/recording/task.go
@@ -0,0 +1,87 @@
+package recording
+
+/*
+In this file we implement task lifecycle management.
+Concrete task works are done in the `runner.go` file.
+*/
+
+import (
+	"bilibili-livestream-archiver/logging"
+	"context"
+	"fmt"
+)
+
+type TaskStatus int
+
+const (
+	StNotStarted TaskStatus = iota
+	StRunning
+	StRestarting
+	StStopped
+)
+
+var (
+	ErrTaskIsAlreadyStarted = fmt.Errorf("task is already started")
+	ErrTaskIsStopped        = fmt.Errorf("restarting a stopped task is not allowed")
+)
+
+// RunningTask is an augmented TaskConfig struct
+// that contains volatile runtime information.
+type RunningTask struct {
+	TaskConfig
+	// ctx: the biggest context this task uses. It may create children contexts.
+	ctx context.Context
+	// result: if the task is ended, here is the returned error
+	result error
+	// status: running status
+	status TaskStatus
+	// hookStarted: called asynchronously when the task is started. This won't be called when restarting.
+	hookStarted func()
+	// hookStopped: called asynchronously when the task is stopped. This won't be called when restarting.
+	hookStopped func()
+	// logger: where to print logs
+	logger logging.Logger
+}
+
+func NewRunningTask(
+	config TaskConfig,
+	ctx context.Context,
+	hookStarted func(),
+	hookStopped func(),
+	logger logging.Logger,
+) RunningTask {
+	return RunningTask{
+		TaskConfig:  config,
+		ctx:         ctx,
+		status:      StNotStarted,
+		hookStarted: hookStarted,
+		hookStopped: hookStopped,
+		logger:      logger,
+	}
+}
+
+func (t *RunningTask) StartTask() error {
+	st := t.status
+	switch st {
+	case StNotStarted:
+		// TODO real start
+		go func() {
+			defer func() { t.status = StStopped }()
+			t.hookStarted()
+			defer t.hookStopped()
+			// do the task
+			_ = t.runTaskWithAutoRestart()
+		}()
+		return nil
+	case StRunning:
+		return ErrTaskIsAlreadyStarted
+	case StRestarting:
+		return ErrTaskIsAlreadyStarted
+	case StStopped:
+		// we don't allow starting a stopped task
+		// because some state needs to be reset
+		// just create a new task and run
+		return ErrTaskIsStopped
+	}
+	panic(fmt.Errorf("invalid task status: %v", st))
+}