feat(scheduler): add Scheduler service interface with host function wrappers for scheduling tasks

plugins/host/go/nd_host_scheduler.go

@@ -0,0 +1,129 @@
+// Code generated by hostgen. DO NOT EDIT.
+//
+// This file contains client wrappers for the Scheduler host service.
+// It is intended for use in Navidrome plugins built with TinyGo.
+
+package main
+
+import (
+	"encoding/json"
+	"errors"
+
+	"github.com/extism/go-pdk"
+)
+
+// scheduler_scheduleonetime is the host function provided by Navidrome.
+//
+//go:wasmimport extism:host/user scheduler_scheduleonetime
+func scheduler_scheduleonetime(int32, uint64, uint64) uint64
+
+// scheduler_schedulerecurring is the host function provided by Navidrome.
+//
+//go:wasmimport extism:host/user scheduler_schedulerecurring
+func scheduler_schedulerecurring(uint64, uint64, uint64) uint64
+
+// scheduler_cancelschedule is the host function provided by Navidrome.
+//
+//go:wasmimport extism:host/user scheduler_cancelschedule
+func scheduler_cancelschedule(uint64) uint64
+
+// SchedulerScheduleOneTimeResponse is the response type for Scheduler.ScheduleOneTime.
+type SchedulerScheduleOneTimeResponse struct {
+	NewScheduleID string `json:"newScheduleID,omitempty"`
+	Error         string `json:"error,omitempty"`
+}
+
+// SchedulerScheduleRecurringResponse is the response type for Scheduler.ScheduleRecurring.
+type SchedulerScheduleRecurringResponse struct {
+	NewScheduleID string `json:"newScheduleID,omitempty"`
+	Error         string `json:"error,omitempty"`
+}
+
+// SchedulerScheduleOneTime calls the scheduler_scheduleonetime host function.
+// ScheduleOneTime schedules a one-time event to be triggered after the specified delay.
+//
+// Parameters:
+//   - delaySeconds: Number of seconds to wait before triggering the event
+//   - payload: Data to be passed to the scheduled event handler
+//   - scheduleID: Optional unique identifier for the scheduled job. If empty, one will be generated
+//
+// Returns the schedule ID that can be used to cancel the job, or an error if scheduling fails.
+func SchedulerScheduleOneTime(delaySeconds int32, payload []byte, scheduleID string) (*SchedulerScheduleOneTimeResponse, error) {
+	payloadMem := pdk.AllocateBytes(payload)
+	defer payloadMem.Free()
+	scheduleIDMem := pdk.AllocateString(scheduleID)
+	defer scheduleIDMem.Free()
+
+	// Call the host function
+	responsePtr := scheduler_scheduleonetime(delaySeconds, payloadMem.Offset(), scheduleIDMem.Offset())
+
+	// Read the response from memory
+	responseMem := pdk.FindMemory(responsePtr)
+	responseBytes := responseMem.ReadBytes()
+
+	// Parse the response
+	var response SchedulerScheduleOneTimeResponse
+	if err := json.Unmarshal(responseBytes, &response); err != nil {
+		return nil, err
+	}
+
+	return &response, nil
+}
+
+// SchedulerScheduleRecurring calls the scheduler_schedulerecurring host function.
+// ScheduleRecurring schedules a recurring event using a cron expression.
+//
+// Parameters:
+//   - cronExpression: Standard cron format expression (e.g., "0 0 * * *" for daily at midnight)
+//   - payload: Data to be passed to each scheduled event handler invocation
+//   - scheduleID: Optional unique identifier for the scheduled job. If empty, one will be generated
+//
+// Returns the schedule ID that can be used to cancel the job, or an error if scheduling fails.
+func SchedulerScheduleRecurring(cronExpression string, payload []byte, scheduleID string) (*SchedulerScheduleRecurringResponse, error) {
+	cronExpressionMem := pdk.AllocateString(cronExpression)
+	defer cronExpressionMem.Free()
+	payloadMem := pdk.AllocateBytes(payload)
+	defer payloadMem.Free()
+	scheduleIDMem := pdk.AllocateString(scheduleID)
+	defer scheduleIDMem.Free()
+
+	// Call the host function
+	responsePtr := scheduler_schedulerecurring(cronExpressionMem.Offset(), payloadMem.Offset(), scheduleIDMem.Offset())
+
+	// Read the response from memory
+	responseMem := pdk.FindMemory(responsePtr)
+	responseBytes := responseMem.ReadBytes()
+
+	// Parse the response
+	var response SchedulerScheduleRecurringResponse
+	if err := json.Unmarshal(responseBytes, &response); err != nil {
+		return nil, err
+	}
+
+	return &response, nil
+}
+
+// SchedulerCancelSchedule calls the scheduler_cancelschedule host function.
+// CancelSchedule cancels a scheduled job identified by its schedule ID.
+//
+// This works for both one-time and recurring schedules. Once cancelled, the job will not trigger
+// any future events.
+//
+// Returns an error if the schedule ID is not found or if cancellation fails.
+func SchedulerCancelSchedule(scheduelID string) error {
+	scheduelIDMem := pdk.AllocateString(scheduelID)
+	defer scheduelIDMem.Free()
+
+	// Call the host function
+	responsePtr := scheduler_cancelschedule(scheduelIDMem.Offset())
+
+	// Read the response from memory
+	responseMem := pdk.FindMemory(responsePtr)
+	errStr := string(responseMem.ReadBytes())
+
+	if errStr != "" {
+		return errors.New(errStr)
+	}
+
+	return nil
+}

plugins/host/scheduler.go

@@ -0,0 +1,42 @@
+package host
+
+import "context"
+
+// SchedulerService provides task scheduling capabilities for plugins.
+//
+// This service allows plugins to schedule both one-time and recurring tasks using
+// cron expressions. All scheduled tasks can be cancelled using their schedule ID.
+//
+//nd:hostservice name=Scheduler permission=scheduler
+type SchedulerService interface {
+	// ScheduleOneTime schedules a one-time event to be triggered after the specified delay.
+	//
+	// Parameters:
+	//   - delaySeconds: Number of seconds to wait before triggering the event
+	//   - payload: Data to be passed to the scheduled event handler
+	//   - scheduleID: Optional unique identifier for the scheduled job. If empty, one will be generated
+	//
+	// Returns the schedule ID that can be used to cancel the job, or an error if scheduling fails.
+	//nd:hostfunc
+	ScheduleOneTime(ctx context.Context, delaySeconds int32, payload []byte, scheduleID string) (newScheduleID string, err error)
+
+	// ScheduleRecurring schedules a recurring event using a cron expression.
+	//
+	// Parameters:
+	//   - cronExpression: Standard cron format expression (e.g., "0 0 * * *" for daily at midnight)
+	//   - payload: Data to be passed to each scheduled event handler invocation
+	//   - scheduleID: Optional unique identifier for the scheduled job. If empty, one will be generated
+	//
+	// Returns the schedule ID that can be used to cancel the job, or an error if scheduling fails.
+	//nd:hostfunc
+	ScheduleRecurring(ctx context.Context, cronExpression string, payload []byte, scheduleID string) (newScheduleID string, err error)
+
+	// CancelSchedule cancels a scheduled job identified by its schedule ID.
+	//
+	// This works for both one-time and recurring schedules. Once cancelled, the job will not trigger
+	// any future events.
+	//
+	// Returns an error if the schedule ID is not found or if cancellation fails.
+	//nd:hostfunc
+	CancelSchedule(ctx context.Context, scheduelID string) error
+}

plugins/host/scheduler_gen.go

@@ -0,0 +1,153 @@
+// Code generated by hostgen. DO NOT EDIT.
+
+package host
+
+import (
+	"context"
+	"encoding/json"
+
+	extism "github.com/extism/go-sdk"
+)
+
+// SchedulerScheduleOneTimeResponse is the response type for Scheduler.ScheduleOneTime.
+type SchedulerScheduleOneTimeResponse struct {
+	NewScheduleID string `json:"newScheduleID,omitempty"`
+	Error         string `json:"error,omitempty"`
+}
+
+// SchedulerScheduleRecurringResponse is the response type for Scheduler.ScheduleRecurring.
+type SchedulerScheduleRecurringResponse struct {
+	NewScheduleID string `json:"newScheduleID,omitempty"`
+	Error         string `json:"error,omitempty"`
+}
+
+// RegisterSchedulerHostFunctions registers Scheduler service host functions.
+// The returned host functions should be added to the plugin's configuration.
+func RegisterSchedulerHostFunctions(service SchedulerService) []extism.HostFunction {
+	return []extism.HostFunction{
+		newSchedulerScheduleOneTimeHostFunction(service),
+		newSchedulerScheduleRecurringHostFunction(service),
+		newSchedulerCancelScheduleHostFunction(service),
+	}
+}
+
+func newSchedulerScheduleOneTimeHostFunction(service SchedulerService) extism.HostFunction {
+	return extism.NewHostFunctionWithStack(
+		"scheduler_scheduleonetime",
+		func(ctx context.Context, p *extism.CurrentPlugin, stack []uint64) {
+			// Read parameters from stack
+			delaySeconds := extism.DecodeI32(stack[0])
+			payload, err := p.ReadBytes(stack[1])
+			if err != nil {
+				return
+			}
+			scheduleID, err := p.ReadString(stack[2])
+			if err != nil {
+				return
+			}
+
+			// Call the service method
+			newscheduleid, err := service.ScheduleOneTime(ctx, delaySeconds, payload, scheduleID)
+			if err != nil {
+				schedulerWriteError(p, stack, err)
+				return
+			}
+			// Write JSON response to plugin memory
+			resp := SchedulerScheduleOneTimeResponse{
+				NewScheduleID: newscheduleid,
+			}
+			schedulerWriteResponse(p, stack, resp)
+		},
+		[]extism.ValueType{extism.ValueTypeI32, extism.ValueTypePTR, extism.ValueTypePTR},
+		[]extism.ValueType{extism.ValueTypePTR},
+	)
+}
+
+func newSchedulerScheduleRecurringHostFunction(service SchedulerService) extism.HostFunction {
+	return extism.NewHostFunctionWithStack(
+		"scheduler_schedulerecurring",
+		func(ctx context.Context, p *extism.CurrentPlugin, stack []uint64) {
+			// Read parameters from stack
+			cronExpression, err := p.ReadString(stack[0])
+			if err != nil {
+				return
+			}
+			payload, err := p.ReadBytes(stack[1])
+			if err != nil {
+				return
+			}
+			scheduleID, err := p.ReadString(stack[2])
+			if err != nil {
+				return
+			}
+
+			// Call the service method
+			newscheduleid, err := service.ScheduleRecurring(ctx, cronExpression, payload, scheduleID)
+			if err != nil {
+				schedulerWriteError(p, stack, err)
+				return
+			}
+			// Write JSON response to plugin memory
+			resp := SchedulerScheduleRecurringResponse{
+				NewScheduleID: newscheduleid,
+			}
+			schedulerWriteResponse(p, stack, resp)
+		},
+		[]extism.ValueType{extism.ValueTypePTR, extism.ValueTypePTR, extism.ValueTypePTR},
+		[]extism.ValueType{extism.ValueTypePTR},
+	)
+}
+
+func newSchedulerCancelScheduleHostFunction(service SchedulerService) extism.HostFunction {
+	return extism.NewHostFunctionWithStack(
+		"scheduler_cancelschedule",
+		func(ctx context.Context, p *extism.CurrentPlugin, stack []uint64) {
+			// Read parameters from stack
+			scheduelID, err := p.ReadString(stack[0])
+			if err != nil {
+				return
+			}
+
+			// Call the service method
+			err = service.CancelSchedule(ctx, scheduelID)
+			if err != nil {
+				// Write error string to plugin memory
+				if ptr, err := p.WriteString(err.Error()); err == nil {
+					stack[0] = ptr
+				}
+				return
+			}
+			// Write empty string to indicate success
+			if ptr, err := p.WriteString(""); err == nil {
+				stack[0] = ptr
+			}
+		},
+		[]extism.ValueType{extism.ValueTypePTR},
+		[]extism.ValueType{extism.ValueTypePTR},
+	)
+}
+
+// schedulerWriteResponse writes a JSON response to plugin memory.
+func schedulerWriteResponse(p *extism.CurrentPlugin, stack []uint64, resp any) {
+	respBytes, err := json.Marshal(resp)
+	if err != nil {
+		schedulerWriteError(p, stack, err)
+		return
+	}
+	respPtr, err := p.WriteBytes(respBytes)
+	if err != nil {
+		stack[0] = 0
+		return
+	}
+	stack[0] = respPtr
+}
+
+// schedulerWriteError writes an error response to plugin memory.
+func schedulerWriteError(p *extism.CurrentPlugin, stack []uint64, err error) {
+	errResp := struct {
+		Error string `json:"error"`
+	}{Error: err.Error()}
+	respBytes, _ := json.Marshal(errResp)
+	respPtr, _ := p.WriteBytes(respBytes)
+	stack[0] = respPtr
+}