Add agent-inject-containers-annotation (#313)

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Unreleased
+
+Features:
+* Add agent-inject-containers annotation [GH-313](https://github.com/hashicorp/vault-k8s/pull/313)
+
 ## 0.14.2 (January 19, 2022)
 
 Changes:

agent-inject/agent/agent.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/hashicorp/vault/sdk/helper/strutil"
 	"github.com/mattbaird/jsonpatch"
 	corev1 "k8s.io/api/core/v1"
 )
@@ -49,6 +50,9 @@ type Agent struct {
 	// sidecar container.
 	ImageName string
 
+	// Containers determine which containers should be injected
+	Containers []string
+
 	// Inject is the flag used to determine if a container should be requested
 	// in a pod request.
 	Inject bool
@@ -93,7 +97,7 @@ type Agent struct {
 	RequestsMem string
 
 	// Secrets are all the templates, the path in Vault where the secret can be
-	//found, and the unique name of the secret which will be used for the filename.
+	// found, and the unique name of the secret which will be used for the filename.
 	Secrets []*Secret
 
 	// ServiceAccountTokenVolume holds details of a volume mount for a
@@ -308,6 +312,7 @@ func New(pod *corev1.Pod, patches []*jsonpatch.JsonPatchOperation) (*Agent, erro
 		Namespace:                 pod.Annotations[AnnotationAgentRequestNamespace],
 		Patches:                   patches,
 		Pod:                       pod,
+		Containers:                []string{},
 		RequestsCPU:               pod.Annotations[AnnotationAgentRequestsCPU],
 		RequestsMem:               pod.Annotations[AnnotationAgentRequestsMem],
 		ServiceAccountTokenVolume: sa,
@@ -363,6 +368,8 @@ func New(pod *corev1.Pod, patches []*jsonpatch.JsonPatchOperation) (*Agent, erro
 		return agent, err
 	}
 
+	agent.Containers = strings.Split(pod.Annotations[AnnotationAgentInjectContainers], ",")
+
 	agent.RevokeGrace, err = agent.revokeGrace()
 	if err != nil {
 		return agent, err
@@ -520,12 +527,14 @@ func (a *Agent) Patch() ([]byte, error) {
 			"/spec/volumes")...)
 	}
 
-	//Add Volume Mounts
+	// Add Volume Mounts
 	for i, container := range a.Pod.Spec.Containers {
-		a.Patches = append(a.Patches, addVolumeMounts(
-			container.VolumeMounts,
-			a.ContainerVolumeMounts(),
-			fmt.Sprintf("/spec/containers/%d/volumeMounts", i))...)
+		if strutil.StrListContains(a.Containers, container.Name) {
+			a.Patches = append(a.Patches, addVolumeMounts(
+				container.VolumeMounts,
+				a.ContainerVolumeMounts(),
+				fmt.Sprintf("/spec/containers/%d/volumeMounts", i))...)
+		}
 	}
 
 	// Init Container
@@ -562,7 +571,7 @@ func (a *Agent) Patch() ([]byte, error) {
 				"/spec/initContainers")...)
 		}
 
-		//Add Volume Mounts
+		// Add Volume Mounts
 		for i, container := range containers {
 			if container.Name == "vault-agent-init" {
 				continue

agent-inject/agent/agent_test.go

@@ -31,6 +31,24 @@ func testPod(annotations map[string]string) *corev1.Pod {
 						},
 					},
 				},
+				{
+					Name: "foo1",
+					VolumeMounts: []corev1.VolumeMount{
+						{
+							Name:      "foo1",
+							MountPath: "/data/foo1",
+						},
+					},
+				},
+				{
+					Name: "foo2",
+					VolumeMounts: []corev1.VolumeMount{
+						{
+							Name:      "foo2",
+							MountPath: "/data/foo2",
+						},
+					},
+				},
 			},
 		},
 	}

agent-inject/agent/annotations.go

@@ -54,6 +54,12 @@ const (
 	// If not provided, a default generic template is used.
 	AnnotationAgentInjectTemplate = "vault.hashicorp.com/agent-inject-template"
 
+	// AnnotationAgentInjectContainers is the key of the annotation that controls
+	// in which containers the secrets volume should be mounted. Multiple containers can
+	// be specified in a comma-separated list. If not provided, the secrets volume will
+	// be mounted in all containers in the pod.
+	AnnotationAgentInjectContainers = "vault.hashicorp.com/agent-inject-containers"
+
 	// AnnotationAgentInjectDefaultTemplate sets the default template type. Possible values
 	// are "json" and "map".
 	AnnotationAgentInjectDefaultTemplate = "vault.hashicorp.com/agent-inject-default-template"
@@ -418,6 +424,14 @@ func Init(pod *corev1.Pod, cfg AgentConfig) error {
 		pod.ObjectMeta.Annotations[AnnotationAgentCacheExitOnErr] = strconv.FormatBool(DefaultAgentCacheExitOnErr)
 	}
 
+	if _, ok := pod.ObjectMeta.Annotations[AnnotationAgentInjectContainers]; !ok {
+		containerNames := make([]string, len(pod.Spec.Containers))
+		for i, v := range pod.Spec.Containers {
+			containerNames[i] = v.Name
+		}
+		pod.ObjectMeta.Annotations[AnnotationAgentInjectContainers] = strings.Join(containerNames, ",")
+	}
+
 	if _, ok := pod.ObjectMeta.Annotations[AnnotationAgentInjectDefaultTemplate]; !ok {
 		pod.ObjectMeta.Annotations[AnnotationAgentInjectDefaultTemplate] = cfg.DefaultTemplate
 	}
@@ -561,7 +575,6 @@ func (a *Agent) tlsSkipVerify() (bool, error) {
 }
 
 func (a *Agent) preserveSecretCase(secretName string) (bool, error) {
-
 	preserveSecretCaseAnnotationName := fmt.Sprintf("%s-%s", AnnotationPreserveSecretCase, secretName)
 
 	var raw string

agent-inject/agent/annotations_test.go

@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"encoding/json"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -955,6 +956,91 @@ func TestAuthConfigAnnotations(t *testing.T) {
 	}
 }
 
+func TestInjectContainers(t *testing.T) {
+	tests := []struct {
+		name          string
+		annotations   map[string]string
+		expectedValue string
+		ExpectedPatch []jsonpatch.JsonPatchOperation
+	}{
+		{
+			name:          "No InjectionContainers annotations",
+			annotations:   map[string]string{},
+			expectedValue: "foobar,foo1,foo2",
+			ExpectedPatch: []jsonpatch.JsonPatchOperation{
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/volumes/-"},
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/containers/0/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/containers/1/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/containers/2/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/initContainers"},
+				{Operation: "add", Path: "/spec/containers/-"},
+				{Operation: "add", Path: "/metadata/annotations/" + EscapeJSONPointer(AnnotationAgentStatus)},
+			},
+		},
+		{
+			name:          "InjectionContainers annotation with container name",
+			annotations:   map[string]string{AnnotationAgentInjectContainers: "foo1"},
+			expectedValue: "foo1",
+			ExpectedPatch: []jsonpatch.JsonPatchOperation{
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/volumes/-"},
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/containers/1/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/initContainers"},
+				{Operation: "add", Path: "/spec/containers/-"},
+				{Operation: "add", Path: "/metadata/annotations/" + EscapeJSONPointer(AnnotationAgentStatus)},
+			},
+		},
+		{
+			name:          "InjectionContainer annotations with multiple containers names",
+			annotations:   map[string]string{AnnotationAgentInjectContainers: "foo1,foo2"},
+			expectedValue: "foo1,foo2",
+			ExpectedPatch: []jsonpatch.JsonPatchOperation{
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/volumes/-"},
+				{Operation: "add", Path: "/spec/volumes"},
+				{Operation: "add", Path: "/spec/containers/1/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/containers/2/volumeMounts/-"},
+				{Operation: "add", Path: "/spec/initContainers"},
+				{Operation: "add", Path: "/spec/containers/-"},
+				{Operation: "add", Path: "/metadata/annotations/" + EscapeJSONPointer(AnnotationAgentStatus)},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pod := testPod(tt.annotations)
+			var patches []*jsonpatch.JsonPatchOperation
+			agentConfig := basicAgentConfig()
+			err := Init(pod, agentConfig)
+			if err != nil {
+				t.Errorf("got error, shouldn't have: %s", err)
+			}
+			agent, err := New(pod, patches)
+			if err != nil {
+				t.Errorf("got error, shouldn't have: %s", err)
+			}
+			patch, err := agent.Patch()
+			if err != nil {
+				t.Errorf("got error, shouldn't have: %s", err)
+			}
+			require.Equal(t, pod.Annotations[AnnotationAgentInjectContainers], tt.expectedValue)
+
+			var output []jsonpatch.JsonPatchOperation
+			require.NoError(t, json.Unmarshal(patch, &output))
+			for i := range output {
+				output[i].Value = nil
+			}
+			require.Equal(t, tt.ExpectedPatch, output)
+
+		})
+	}
+
+}
+
 func TestDefaultTemplateOverride(t *testing.T) {
 	tests := []struct {
 		annotations   map[string]string