flow: improve store

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

flow/flow.go

@@ -4,12 +4,41 @@ package flow
 import (
 	"context"
 	"errors"
+
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 var (
 	ErrStepNotExists = errors.New("step not exists")
+	ErrMissingClient = errors.New("client not set")
 )
 
+// RawMessage is a raw encoded JSON value.
+// It implements Marshaler and Unmarshaler and can be used to delay decoding or precompute a encoding.
+type RawMessage []byte
+
+// MarshalJSON returns m as the JSON encoding of m.
+func (m *RawMessage) MarshalJSON() ([]byte, error) {
+	if m == nil {
+		return []byte("null"), nil
+	}
+	return *m, nil
+}
+
+// UnmarshalJSON sets *m to a copy of data.
+func (m *RawMessage) UnmarshalJSON(data []byte) error {
+	if m == nil {
+		return errors.New("RawMessage UnmarshalJSON on nil pointer")
+	}
+	*m = append((*m)[0:0], data...)
+	return nil
+}
+
+type Message struct {
+	Header metadata.Metadata
+	Body   RawMessage
+}
+
 // Step represents dedicated workflow step
 type Step interface {
 	// ID returns step id
@@ -17,7 +46,7 @@ type Step interface {
 	// Endpoint returns rpc endpoint service_name.service_method or broker topic
 	Endpoint() string
 	// Execute step run
-	Execute(ctx context.Context, req interface{}, opts ...ExecuteOption) error
+	Execute(ctx context.Context, req *Message, opts ...ExecuteOption) (*Message, error)
 	// Requires returns dependent steps
 	Requires() []string
 	// Options returns step options
@@ -26,20 +55,41 @@ type Step interface {
 	Require(steps ...Step) error
 	// String
 	String() string
+	// GetStatus returns step status
+	GetStatus() Status
+	// SetStatus sets the step status
+	SetStatus(Status)
+	// Request returns step request message
+	Request() *Message
+	// Response returns step response message
+	Response() *Message
 }
 
+type Status int
+
+const (
+	StatusPending Status = iota
+	StatusRunning
+	StatusFailure
+	StatusSuccess
+	StatusAborted
+	StatusSuspend
+)
+
 // Workflow contains all steps to execute
 type Workflow interface {
 	// ID returns id of the workflow
 	ID() string
+	// Execute workflow with args, return execution id and error
+	Execute(ctx context.Context, req *Message, opts ...ExecuteOption) (string, error)
+	// RemoveSteps remove steps from workflow
+	RemoveSteps(steps ...Step) error
+	// AppendSteps append steps to workflow
+	AppendSteps(steps ...Step) error
+	// Status returns workflow status
+	Status() Status
 	// Steps returns steps slice where parallel steps returned on the same level
 	Steps() ([][]Step, error)
-	// Execute workflow with args, return execution id and error
-	Execute(ctx context.Context, req interface{}, opts ...ExecuteOption) (string, error)
-	// RemoveSteps remove steps from workflow
-	RemoveSteps(ctx context.Context, steps ...Step) error
-	// AppendSteps append steps to workflow
-	AppendSteps(ctx context.Context, steps ...Step) error
 }
 
 // Flow the base interface to interact with workflows