Parser separation

api/broker/binding_request_parser/binding-request-parser.go

@@ -0,0 +1,90 @@
+package binding_request_parser
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser/legacy"
+	brp "code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser/types"
+	"code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser/v0_1"
+	"code.cloudfoundry.org/app-autoscaler/src/autoscaler/models"
+)
+
+// The parser for bind-requests needs to deal with a multi-version-schema. It therefore is a
+// aggregation of multiple dedicated parsers where each one is specialised for precisely one
+// particular schema-version. The top-level-parser then just extracts the schema that is referenced
+// within a binding-request and dispatches the parsing to the responsible one of the specialised
+// parsers.
+//
+// All the specialised parsers as well as the top-level one share the same interface `Parser` (as
+// well as some other dedicated types) within the sub-package `types`.
+
+// ================================================================================
+// To-level parser
+// ================================================================================
+
+type BindRequestParser struct {
+	legacyParser legacy.BindingRequestParser
+	v0_1Parser   v0_1.BindingRequestParser
+}
+
+var _ brp.Parser = BindRequestParser{}
+
+func NewFromParsers(
+	legacyParser legacy.BindingRequestParser, v0_1Parser v0_1.BindingRequestParser,
+) BindRequestParser {
+	return BindRequestParser{
+		legacyParser: legacyParser,
+		v0_1Parser:   v0_1Parser,
+	}
+}
+
+func New(
+	legacySchemaPath, v0_1SchemaPath string,
+	defaultCustomMetricsCredentialType models.CustomMetricsBindingAuthScheme,
+) (BindRequestParser, error) {
+	legacyParser, err := legacy.New(legacySchemaPath, defaultCustomMetricsCredentialType)
+	if err != nil {
+		return BindRequestParser{}, fmt.Errorf("failed to create legacy binding-request-parser: %w", err)
+	}
+
+	v0_1Parser, err := v0_1.NewFromFile(v0_1SchemaPath, defaultCustomMetricsCredentialType)
+	if err != nil {
+		return BindRequestParser{}, fmt.Errorf("failed to create v0.1 binding-request-parser: %w", err)
+	}
+
+	return NewFromParsers(legacyParser, v0_1Parser), nil
+}
+
+func (p BindRequestParser) Parse(
+	bindingReqParams string, ccAppGuid models.GUID,
+) (models.AppScalingConfig, error) {
+	schemaVersion, err := extractSchemaVersion(bindingReqParams)
+	if err != nil {
+		return models.AppScalingConfig{}, err
+	}
+
+	switch schemaVersion {
+	case "0.1":
+		return p.v0_1Parser.Parse(bindingReqParams, ccAppGuid)
+	case "": // The legacy-schema is the only one without a version-identifier;
+		return p.legacyParser.Parse(bindingReqParams, ccAppGuid)
+	default:
+		return models.AppScalingConfig{}, fmt.Errorf(
+			"unsupported schema-version '%s' referenced in binding-request", schemaVersion)
+	}
+}
+
+func extractSchemaVersion(bindingReqParams string) (string, error) {
+	type schemaHolder struct {
+		Schema string `json:"schema-version,omitempty"`
+	}
+
+	var holder schemaHolder
+	err := json.Unmarshal([]byte(bindingReqParams), &holder)
+	if err != nil {
+		return "", fmt.Errorf("failed to extract schema-version from binding-request: %w", err)
+	}
+
+	return holder.Schema, nil
+}

api/broker/binding_request_parser/binding-request-parser_suite_test.go

@@ -0,0 +1,13 @@
+package binding_request_parser_test
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"testing"
+)
+
+func TestServer(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "BindingRequestParser test suite")
+}

api/broker/binding_request_parser/binding-request-parser_test.go

@@ -0,0 +1,164 @@
+package binding_request_parser_test
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	br "code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser"
+	lp "code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser/legacy"
+	brp_v1 "code.cloudfoundry.org/app-autoscaler/src/autoscaler/api/broker/binding_request_parser/v0_1"
+	"code.cloudfoundry.org/app-autoscaler/src/autoscaler/models"
+)
+
+var _ = Describe("BindingRequestParsers", func() {
+	const v0_1SchemaFilePath string = "file://./v0_1/meta.schema.json"
+	const legacySchemaFilePath string = "file://./legacy/schema.json"
+
+	const validModernBindingRequestRaw string = `
+	{
+		"schema-version": "0.1",
+		"configuration": {
+			  "app_guid": "8d0cee08-23ad-4813-a779-ad8118ea0b91",
+			  "custom_metrics": {
+				  "metric_submission_strategy": {
+					  "allow_from": "bound_app"
+				  }
+			  }
+		},
+		"instance_min_count": 1,
+		"instance_max_count": 5,
+		"scaling_rules": [
+			  {
+				  "metric_type": "memoryused",
+				  "threshold": 30,
+				  "operator": "<",
+				  "adjustment": "-1"
+			  }
+		]
+	}`
+	const validLegacyBindingRequestRaw string = `
+		{
+		 "configuration": {
+			 "custom_metrics": {
+			   "metric_submission_strategy": {
+				   "allow_from": "bound_app"
+			   }
+			 }
+		 },
+		 "instance_min_count": 1,
+		 "instance_max_count": 4,
+		 "scaling_rules": [
+		   {
+			 "metric_type": "memoryutil",
+			 "breach_duration_secs": 600,
+			 "threshold": 30,
+			 "operator": "<",
+			 "cool_down_secs": 300,
+			 "adjustment": "-1"
+		   },
+		   {
+			 "metric_type": "memoryutil",
+			 "breach_duration_secs": 600,
+			 "threshold": 90,
+			 "operator": ">=",
+			 "cool_down_secs": 300,
+			 "adjustment": "+1"
+		   }
+		 ]
+	   }`
+
+	Describe("v0.1_BindingRequestParser", func() {
+		var (
+			v0_1Parser brp_v1.BindingRequestParser
+			err        error
+		)
+		var _ = BeforeEach(func() {
+			v0_1Parser, err = brp_v1.NewFromFile(v0_1SchemaFilePath, models.X509Certificate)
+			Expect(err).NotTo(HaveOccurred())
+		})
+		Context("When using the new format for binding-requests", func() {
+			Context("and parsing a valid and complete one", func() {
+				It("should return a correctly populated BindingRequestParameters", func() {
+					bindingRequestRaw := validModernBindingRequestRaw
+					ccAppGuid := models.GUID("") // Raw request is about creating a service-key;
+
+					bindingRequest, err := v0_1Parser.Parse(bindingRequestRaw, ccAppGuid)
+
+					Expect(err).NotTo(HaveOccurred())
+					Expect(bindingRequest.GetConfiguration().GetAppGUID()).To(
+						Equal(models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")))
+				})
+			})
+		})
+	})
+
+	Describe("LegacyBindingRequestParser", func() {
+		var (
+			legacyParser lp.BindingRequestParser
+			err          error
+		)
+		var _ = BeforeEach(func() {
+			Expect(err).NotTo(HaveOccurred())
+			legacyParser, err = lp.New(legacySchemaFilePath, models.X509Certificate)
+			Expect(err).NotTo(HaveOccurred())
+		})
+
+		Context("When using the legacy format for binding-requests", func() {
+			It("should return a correctly populated BindingRequestParameters", func() {
+				bindingRequestRaw := validLegacyBindingRequestRaw
+				appGuidFromCC := models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")
+
+				appScalingConfig, err := legacyParser.Parse(bindingRequestRaw, appGuidFromCC)
+
+				Expect(err).NotTo(HaveOccurred())
+				Expect(appScalingConfig.GetConfiguration().GetAppGUID()).
+					To(Equal(models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")))
+				// 🚧 To-do: Add a few more field-comparisons;
+			})
+		})
+	})
+
+	Describe("CombinedBindingRequestParser", func() {
+		var (
+			parser br.BindRequestParser
+			err    error
+		)
+		var _ = BeforeEach(func() {
+			parser, err = br.New(
+				legacySchemaFilePath,
+				v0_1SchemaFilePath,
+				models.X509Certificate,
+			)
+			Expect(err).NotTo(HaveOccurred())
+		})
+
+		Context("When using the v0.1 schema for binding-requests", func() {
+			Context("and parsing a valid and complete one", func() {
+				It("should return a correctly populated BindingRequestParameters", func() {
+					bindingRequestRaw := validModernBindingRequestRaw
+					appGuidFromCC := models.GUID("")
+
+					bindingRequest, err := parser.Parse(bindingRequestRaw, appGuidFromCC)
+
+					Expect(err).NotTo(HaveOccurred())
+					Expect(bindingRequest.GetConfiguration().GetAppGUID()).To(
+						Equal(models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")))
+				})
+			})
+		})
+
+		Context("When using the legacy schema for binding-requests", func() {
+			It("should return a correctly populated BindingRequestParameters", func() {
+				bindingRequestRaw := validLegacyBindingRequestRaw
+				appGuidFromCC := models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")
+
+				bindingRequest, err := parser.Parse(bindingRequestRaw, appGuidFromCC)
+
+				Expect(err).NotTo(HaveOccurred())
+				Expect(bindingRequest.GetConfiguration().GetAppGUID()).
+					To(Equal(models.GUID("8d0cee08-23ad-4813-a779-ad8118ea0b91")))
+				// 🚧 To-do: Add a few more field-comparisons;
+			})
+		})
+	})
+})