feat: adds support for workflow initializers

Author: cludden

internal/plugin/service.go

@@ -17,6 +17,7 @@ const (
 	clientPkg     = "go.temporal.io/sdk/client"
 	enumsPkg      = "go.temporal.io/api/enums/v1"
 	expressionPkg = "github.com/cludden/protoc-gen-go-temporal/pkg/expression"
+	helpersPkg    = "github.com/cludden/protoc-gen-go-temporal/pkg/helpers"
 	temporalPkg   = "go.temporal.io/sdk/temporal"
 	updatePkg     = "go.temporal.io/api/update/v1"
 	uuidPkg       = "github.com/google/uuid"

internal/plugin/worker.go

@@ -93,6 +93,20 @@ func (svc *Service) genWorkerBuilderFunction(f *g.File, workflow string) {
 							}),
 						)
 
+						fn.If(
+							g.List(g.Id("initializable"), g.Id("ok")).Op(":=").Id("wf").Op(".").Parens(g.Qual(helpersPkg, "Initializable")),
+							g.Id("ok"),
+						).Block(
+							g.If(g.Err().Op(":=").Id("initializable").Dot("Initialize").Call(g.Id("ctx")), g.Err().Op("!=").Nil()).Block(
+								g.ReturnFunc(func(returnVals *g.Group) {
+									if hasOutput {
+										returnVals.Nil()
+									}
+									returnVals.Err()
+								}),
+							),
+						)
+
 						// register query handlers
 						for _, q := range opts.GetQuery() {
 							query := q.GetRef()

pkg/helpers/helpers.go

@@ -0,0 +1,8 @@
+package helpers
+
+import "go.temporal.io/sdk/workflow"
+
+// Initializable describes a Workflow that supports initialization prior to registering signal, query, or update handlers
+type Initializable interface {
+	Initialize(ctx workflow.Context) error
+}