tools/awssdkpatch: add multiclient support (hashicorp#37540)

The new `-multiclient` flag supports services where both V1 and V2 AWS SDK clients are used simultaneously. This is a common pattern for large services (e.g. `ec2`), where the migration will take place in parts. When set, the generated patch file will include additional patches to migrate tagging and filter helper functions to the appropriate V2 variant.

GNUmakefile

@@ -85,7 +85,7 @@ awssdkpatch-gen: awssdkpatch ## Generate a patch file using awssdkpatch
 		echo "PKG=foo make awssdkpatch-gen" ; \
 		exit 1 ; \
 	fi
-	@awssdkpatch -service $(PKG)
+	@awssdkpatch $(AWSSDKPATCH_OPTS) -service $(PKG)
 
 awssdkpatch: prereq-go ## Install awssdkpatch
 	cd tools/awssdkpatch && $(GO_VER) install github.com/hashicorp/terraform-provider-aws/tools/awssdkpatch

docs/aws-go-sdk-migrations.md

@@ -43,10 +43,18 @@ PKG=ec2 make awssdkpatch-apply
 You may also optionally generate the patch and use [`gopatch`](https://github.com/uber-go/gopatch) to preview differences before modfiying any files.
 
 ```console
-PKG=ec2 make awssdkpatch-gen
+make awssdkpatch-gen PKG=ec2
 gopatch -d -p awssdk.patch ./internal/service/ec2/...
 ```
 
+#### Custom options
+
+To set additional `awssdkpatch` flags during patch generation, use the `AWSSDKPATCH_OPTS` environment variable.
+
+```console
+make awssdkpatch-gen PKG=ec2 AWSSDKPATCH_OPTS="-multiclient"
+```
+
 ## Imports
 
 In each go source file with a V1 SDK import, the library should be replaced with V2:

tools/awssdkpatch/README.md

@@ -17,6 +17,8 @@ Usage: awssdkpatch [flags]
 Flags:
   -importalias string
         alias that the service package is imported as (optional)
+  -multiclient
+        whether the service supports both v1 and v2 clients (optional)
   -out string
         output file (optional) (default "awssdk.patch")
   -service string
@@ -51,3 +53,11 @@ If the service uses an import alias, include the `-importalias` flag when genera
 ```console
 awssdkpatch -service dms -importalias dms
 ```
+
+### Multiple clients
+
+If the service supports both V1 and V2 AWS SDK clients (a common pattern in large services which are migrated in parts), include the `-multiclient` flag when generating the patch file:
+
+```console
+awssdkpatch -service ec2 -multiclient
+```

tools/awssdkpatch/main.go

@@ -21,6 +21,7 @@ import (
 
 var (
 	importalias string
+	multiclient bool
 	out         string
 	service     string
 
@@ -32,6 +33,7 @@ type TemplateData struct {
 	GoV1Package        string
 	GoV1ClientTypeName string
 	GoV2Package        string
+	MultiClient        bool
 	ImportAlias        string
 	ProviderPackage    string
 	InputOutputTypes   []string
@@ -48,6 +50,7 @@ func main() {
 		flag.PrintDefaults()
 	}
 	flag.StringVar(&importalias, "importalias", "", "alias that the service package is imported as (optional)")
+	flag.BoolVar(&multiclient, "multiclient", false, "whether the service supports both v1 and v2 clients (optional)")
 	flag.StringVar(&out, "out", "awssdk.patch", "output file (optional)")
 	flag.StringVar(&service, "service", "", "service to migrate (required)")
 	flag.Parse()
@@ -113,6 +116,7 @@ func getPackageData(sd data.ServiceRecord) (TemplateData, error) {
 		GoV1ClientTypeName: sd.GoV1ClientTypeName(),
 		GoV2Package:        sd.GoV2Package(),
 		ImportAlias:        importalias,
+		MultiClient:        multiclient,
 		ProviderPackage:    providerPackage,
 	}
 

tools/awssdkpatch/patch.tmpl

@@ -176,3 +176,59 @@ var x identifier
 @@
 +import "github.com/hashicorp/terraform-provider-aws/internal/enum"
 enum.x
+
+{{- if .MultiClient }}
+# Replace generated Tags function with the V2 variant.
+@@
+@@
+-Tags(...)
++TagsV2(...)
+
+# Replace generated KeyValueTags function with the V2 variant.
+@@
+@@
+-KeyValueTags(...)
++keyValueTagsV2(...)
+
+# Replace generated getTagsIn function with the V2 variant.
+@@
+@@
+-getTagsIn(...)
++getTagsInV2(...)
+
+# Replace generated getTagSpecificationsIn function with the V2 variant.
+@@
+@@
+-getTagSpecificationsIn(...)
++getTagSpecificationsInV2(...)
+
+# Replace generated setTagsOut function with the V2 variant.
+@@
+@@
+-setTagsOut(...)
++setTagsOutV2(...)
+
+# Replace generated createTags function with the V2 variant.
+@@
+@@
+-createTags(...)
++createTagsV2(...)
+
+# Replace generated updateTags function with the V2 variant.
+@@
+@@
+-updateTags(...)
++updateTagsV2(...)
+
+# Replace generated newTagFilterList function with the V2 variant.
+@@
+@@
+-newTagFilterList(...)
++newTagFilterListV2(...)
+
+# Replace generated newCustomFilterList function with the V2 variant.
+@@
+@@
+-newCustomFilterList(...)
++newCustomFilterListV2(...)
+{{- end }}