Read bindings from VCAP_SERVICES (#228)

Read bindings from VCAP_SERVICES

Signed-off-by: Ralf Pannemans <[email protected]>

Author: c0d1ngm0nk3y

platform.go

@@ -17,6 +17,7 @@
 package libcnb
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -41,6 +42,9 @@ const (
 	// See the Service Binding Specification for Kubernetes for more details - https://k8s-service-bindings.github.io/spec/
 	EnvServiceBindings = "SERVICE_BINDING_ROOT"
 
+	// EnvVcapServices is the name of the environment variable that contains the bindings in cloudfoundry
+	EnvVcapServices = "VCAP_SERVICES"
+
 	// EnvCNBBindings is the name of the environment variable that contains the path to the CNB bindings directory.
 	// See the CNB bindings extension spec for more details - https://github.com/buildpacks/spec/blob/main/extensions/bindings.md
 	//
@@ -113,6 +117,34 @@ func NewBindingFromPath(path string) (Binding, error) {
 	return NewBinding(filepath.Base(path), path, secret), nil
 }
 
+type vcapServicesBinding struct {
+	Name        string            `json:"name"`
+	Credentials map[string]string `json:"credentials"`
+}
+
+// NewBindingsFromVcapServicesEnv creates a new instance from all the bindings given from the VCAP_SERVICES.
+func NewBindingsFromVcapServicesEnv(content string) (Bindings, error) {
+	var contentTyped map[string][]vcapServicesBinding
+
+	err := json.Unmarshal([]byte(content), &contentTyped)
+	if err != nil {
+		return Bindings{}, nil
+	}
+
+	bindings := Bindings{}
+	for t, bArray := range contentTyped {
+		for _, b := range bArray {
+			bindings = append(bindings, Binding{
+				Name:   b.Name,
+				Type:   t,
+				Secret: b.Credentials,
+			})
+		}
+	}
+
+	return bindings, nil
+}
+
 func (b Binding) String() string {
 	var s []string
 	for k := range b.Secret {
@@ -163,6 +195,10 @@ func NewBindingsForLaunch() (Bindings, error) {
 		return NewBindingsFromPath(path)
 	}
 
+	if content, ok := os.LookupEnv(EnvVcapServices); ok {
+		return NewBindingsFromVcapServicesEnv(content)
+	}
+
 	return Bindings{}, nil
 }
 
@@ -201,6 +237,10 @@ func NewBindingsForBuild(platformDir string) (Bindings, error) {
 	if path, ok := os.LookupEnv(EnvCNBBindings); ok {
 		return NewBindingsFromPath(path)
 	}
+
+	if content, ok := os.LookupEnv(EnvVcapServices); ok {
+		return NewBindingsFromVcapServicesEnv(content)
+	}
 	return NewBindingsFromPath(filepath.Join(platformDir, "bindings"))
 }
 

platform_test.go

@@ -40,6 +40,57 @@ func testPlatform(t *testing.T, context spec.G, it spec.S) {
 		path = filepath.Join(platformPath, "bindings")
 	})
 
+	context("Cloudfoundry VCAP_SERVICES", func() {
+		context("Build", func() {
+			it("creates a bindings from VCAP_SERVICES", func() {
+				content, err := os.ReadFile("testdata/vcap_services.json")
+				Expect(err).NotTo(HaveOccurred())
+				t.Setenv(libcnb.EnvVcapServices, string(content))
+
+				bindings, err := libcnb.NewBindingsForBuild("")
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(bindings).To(HaveLen(2))
+
+				types := []string{bindings[0].Type, bindings[1].Type}
+				Expect(types).To(ContainElements("elephantsql", "sendgrid"))
+			})
+
+			it("creates empty bindings from empty VCAP_SERVICES", func() {
+				t.Setenv(libcnb.EnvVcapServices, "{}")
+
+				bindings, err := libcnb.NewBindingsForBuild("")
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(bindings).To(HaveLen(0))
+			})
+		})
+
+		context("Launch", func() {
+			it("creates a bindings from VCAP_SERVICES", func() {
+				content, err := os.ReadFile("testdata/vcap_services.json")
+				Expect(err).NotTo(HaveOccurred())
+				t.Setenv(libcnb.EnvVcapServices, string(content))
+
+				bindings, err := libcnb.NewBindingsForLaunch()
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(bindings).To(HaveLen(2))
+				types := []string{bindings[0].Type, bindings[1].Type}
+				Expect(types).To(ContainElements("elephantsql", "sendgrid"))
+			})
+
+			it("creates empty bindings from empty VCAP_SERVICES", func() {
+				t.Setenv(libcnb.EnvVcapServices, "{}")
+
+				bindings, err := libcnb.NewBindingsForLaunch()
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(bindings).To(HaveLen(0))
+			})
+		})
+	})
+
 	context("CNB Bindings", func() {
 		it.Before(func() {
 			Expect(os.MkdirAll(filepath.Join(path, "alpha", "metadata"), 0755)).To(Succeed())

testdata/vcap_services.json

@@ -0,0 +1,44 @@
+{
+    "elephantsql": [
+      {
+        "name": "elephantsql-binding-c6c60",
+        "binding_guid": "44ceb72f-100b-4f50-87a2-7809c8b42b8d",
+        "binding_name": "elephantsql-binding-c6c60",
+        "instance_guid": "391308e8-8586-4c42-b464-c7831aa2ad22",
+        "instance_name": "elephantsql-c6c60",
+        "label": "elephantsql",
+        "tags": [
+          "postgres",
+          "postgresql",
+          "relational"
+        ],
+        "plan": "turtle",
+        "credentials": {
+          "uri": "postgres://exampleuser:[email protected]:5432/exampleuser"
+        },
+        "syslog_drain_url": null,
+        "volume_mounts": []
+      }
+    ],
+    "sendgrid": [
+      {
+        "name": "mysendgrid",
+        "binding_guid": "6533b1b6-7916-488d-b286-ca33d3fa0081",
+        "binding_name": null,
+        "instance_guid": "8c907d0f-ec0f-44e4-87cf-e23c9ba3925d",
+        "instance_name": "mysendgrid",
+        "label": "sendgrid",
+        "tags": [
+          "smtp"
+        ],
+        "plan": "free",
+        "credentials": {
+          "hostname": "smtp.example.com",
+          "username": "QvsXMbJ3rK",
+          "password": "HCHMOYluTv"
+        },
+        "syslog_drain_url": null,
+        "volume_mounts": []
+      }
+    ]
+}