Merge pull request #13 from utilitywarehouse/prepend-init

Add prependInitContainers option

docs/sidecar-configuration-format.md

@@ -44,6 +44,9 @@ inherits: "some-sidecar.yaml"
 # https://medium.com/@marko.luksa/delaying-application-start-until-sidecar-is-ready-2ec2d21a7b74
 prependContainers: false
 
+# prependInitContainers is the same as above, but for initContainers
+prependInitContainers: false
+
 containers:
 # we inject a nginx container
 - name: sidecar-nginx

internal/pkg/config/config.go

@@ -32,18 +32,19 @@ var (
 
 // InjectionConfig is a specific instance of a injected config, for a given annotation
 type InjectionConfig struct {
-	Name               string               `json:"name"`
-	Inherits           string               `json:"inherits"`
-	Containers         []corev1.Container   `json:"containers"`
-	Volumes            []corev1.Volume      `json:"volumes"`
-	Environment        []corev1.EnvVar      `json:"env"`
-	VolumeMounts       []corev1.VolumeMount `json:"volumeMounts"`
-	HostAliases        []corev1.HostAlias   `json:"hostAliases"`
-	HostNetwork        bool                 `json:"hostNetwork"`
-	HostPID            bool                 `json:"hostPID"`
-	InitContainers     []corev1.Container   `json:"initContainers"`
-	ServiceAccountName string               `json:"serviceAccountName"`
-	PrependContainers  bool                 `json:"prependContainers"`
+	Name                  string               `json:"name"`
+	Inherits              string               `json:"inherits"`
+	Containers            []corev1.Container   `json:"containers"`
+	Volumes               []corev1.Volume      `json:"volumes"`
+	Environment           []corev1.EnvVar      `json:"env"`
+	VolumeMounts          []corev1.VolumeMount `json:"volumeMounts"`
+	HostAliases           []corev1.HostAlias   `json:"hostAliases"`
+	HostNetwork           bool                 `json:"hostNetwork"`
+	HostPID               bool                 `json:"hostPID"`
+	InitContainers        []corev1.Container   `json:"initContainers"`
+	ServiceAccountName    string               `json:"serviceAccountName"`
+	PrependContainers     bool                 `json:"prependContainers"`
+	PrependInitContainers bool                 `json:"prependInitContainers"`
 
 	version string
 }

internal/pkg/config/config_test.go

@@ -206,6 +206,18 @@ var (
 			InitContainerCount: 0,
 			PrependContainers:  true,
 		},
+		"prepend-init-containers": testhelper.ConfigExpectation{
+			Name:                  "prepend-init-containers",
+			Version:               "latest",
+			Path:                  fixtureSidecarsDir + "/prepend-init-containers.yaml",
+			EnvCount:              0,
+			ContainerCount:        0,
+			VolumeCount:           0,
+			VolumeMountCount:      0,
+			HostAliasCount:        0,
+			InitContainerCount:    2,
+			PrependInitContainers: true,
+		},
 	}
 )
 

internal/pkg/testing/config.go

@@ -12,17 +12,18 @@ type ConfigExpectation struct {
 	// version is the parsed version string, or "latest" if omitted
 	Version string
 	// Path is the path to the YAML to load the sidecar yaml from
-	Path               string
-	EnvCount           int
-	ContainerCount     int
-	VolumeCount        int
-	VolumeMountCount   int
-	HostAliasCount     int
-	HostNetwork        bool
-	HostPID            bool
-	InitContainerCount int
-	ServiceAccount     string
-	PrependContainers  bool
+	Path                  string
+	EnvCount              int
+	ContainerCount        int
+	VolumeCount           int
+	VolumeMountCount      int
+	HostAliasCount        int
+	HostNetwork           bool
+	HostPID               bool
+	InitContainerCount    int
+	ServiceAccount        string
+	PrependContainers     bool
+	PrependInitContainers bool
 
 	// LoadError is an error, if any, that is expected during load
 	LoadError error

pkg/server/webhook.go

@@ -470,7 +470,12 @@ func createPatch(pod *corev1.Pod, inj *config.InjectionConfig, annotations map[s
 		// this mutates inj.InitContainers with our environment vars
 		mutatedInjectedInitContainers := mergeEnvVars(inj.Environment, inj.InitContainers)
 		mutatedInjectedInitContainers = mergeVolumeMounts(inj.VolumeMounts, mutatedInjectedInitContainers)
-		patch = append(patch, appendContainers(pod.Spec.InitContainers, mutatedInjectedInitContainers, "/spec/initContainers")...)
+		// then, add containers to the patch
+		if inj.PrependInitContainers {
+			patch = append(patch, prependContainers(pod.Spec.InitContainers, mutatedInjectedInitContainers, "/spec/initContainers")...)
+		} else {
+			patch = append(patch, appendContainers(pod.Spec.InitContainers, mutatedInjectedInitContainers, "/spec/initContainers")...)
+		}
 	}
 
 	{ // container injections

pkg/server/webhook_test.go

@@ -38,6 +38,7 @@ var (
 	obj7v2      = "test/fixtures/k8s/object7-v2.yaml"
 	obj7v3      = "test/fixtures/k8s/object7-badrequestformat.yaml"
 	obj8        = "test/fixtures/k8s/object8.yaml"
+	obj9        = "test/fixtures/k8s/object9.yaml"
 	badSidecar  = "test/fixtures/k8s/bad-sidecar.yaml"
 
 	// tests to check config loading of sidecars
@@ -54,6 +55,7 @@ var (
 		{configuration: obj7v2, expectedSidecar: "init-containers:v2"},
 		{configuration: obj7v3, expectedSidecar: "", expectedError: ErrRequestedSidecarNotFound},
 		{configuration: obj8, expectedSidecar: "prepend-containers:latest"},
+		{configuration: obj9, expectedSidecar: "prepend-init-containers:latest"},
 		{configuration: badSidecar, expectedSidecar: "", expectedError: ErrRequestedSidecarNotFound},
 	}
 
@@ -63,6 +65,7 @@ var (
 		{name: "sidecar-test-1", allowed: true, patchExpected: true},
 		{name: "env-override", allowed: true, patchExpected: true},
 		{name: "prepend-containers", allowed: true, patchExpected: true},
+		{name: "prepend-init-containers", allowed: true, patchExpected: true},
 		{name: "service-account", allowed: true, patchExpected: true},
 		{name: "service-account-already-set", allowed: true, patchExpected: true},
 		{name: "service-account-set-default", allowed: true, patchExpected: true},

test/fixtures/k8s/admissioncontrol/patch/prepend-init-containers.json

@@ -0,0 +1,38 @@
+[
+  {
+    "op": "add",
+    "path": "/spec/initContainers",
+    "value": [
+      {
+        "image": "foo:69",
+        "name": "sidecar-existing-vm",
+        "ports": [
+          {
+            "containerPort": 420
+          }
+        ],
+        "resources": {}
+      }
+    ]
+  },
+  {
+    "op": "add",
+    "path": "/spec/initContainers/0",
+    "value": {
+      "image": "nginx:1.12.2",
+      "imagePullPolicy": "IfNotPresent",
+      "name": "sidecar-add-vm",
+      "ports": [
+        {
+          "containerPort": 80
+        }
+      ],
+      "resources": {}
+    }
+  },
+  {
+    "op": "add",
+    "path": "/metadata/annotations/injector.unittest.com~1status",
+    "value": "injected"
+  }
+]

test/fixtures/k8s/admissioncontrol/request/prepend-init-containers.yaml

@@ -0,0 +1,9 @@
+---
+# this is an AdmissionRequest object
+# https://godoc.org/k8s.io/api/admission/v1#AdmissionRequest
+object:
+  metadata:
+    annotations:
+      injector.unittest.com/request: "prepend-init-containers"
+  spec:
+    initContainers: []

test/fixtures/k8s/object9.yaml

@@ -0,0 +1,4 @@
+name: object8
+namespace: unittest
+annotations:
+  "injector.unittest.com/request": "prepend-init-containers"

test/fixtures/sidecars/prepend-init-containers.yaml

@@ -0,0 +1,12 @@
+name: prepend-init-containers
+initContainers:
+  - name: sidecar-add-vm
+    image: nginx:1.12.2
+    imagePullPolicy: IfNotPresent
+    ports:
+      - containerPort: 80
+  - name: sidecar-existing-vm
+    image: foo:69
+    ports:
+      - containerPort: 420
+prependInitContainers: true