### Install gator from source

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Build and install the gator binary directly from the Gatekeeper repository.

```bash
go install github.com/open-policy-agent/gatekeeper/v3/cmd/gator@master
```

--------------------------------

### Install policies

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Install single or multiple policies, bundles, or perform dry-run installations.

```bash
# Install a single policy (template only)
gator policy install k8srequiredlabels

# Install multiple policies
gator policy install k8srequiredlabels k8scontainerlimits

# Install a bundle (templates + constraints)
gator policy install --bundle pod-security-baseline

# Install with warn enforcement (for safe rollout)
gator policy install --bundle pod-security-baseline --enforcement-action=warn

# Preview changes without applying
gator policy install --bundle pod-security-baseline --dry-run
```

--------------------------------

### Install policies using gator policy

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Install individual policies or pre-configured bundles.

```bash
# Template only
gator policy install k8srequiredlabels

# Bundle includes templates + constraints
gator policy install --bundle pod-security-baseline
```

--------------------------------

### Run gator verify commands

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Command line examples for executing test suites.

```bash
gator verify suite.yaml  
```

```bash
gator verify ./...  
```

```bash
gator verify path/to/suites/... --run "disallowed"  
```

--------------------------------

### Install gator via Homebrew

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Install the gator CLI using the Homebrew package manager on macOS or Linux.

```bash
brew install gator
```

--------------------------------

### Declare an ExpansionTemplate in a Suite

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example configuration for testing generated resources using an expansion template.

```yaml
apiVersion: test.gatekeeper.sh/v1alpha1  
kind: Suite  
tests:  
- name: expansion  
  template: template.yaml  
  constraint: constraint.yaml  
  expansion: expansion.yaml  
  cases:  
  - name: example-expand  
    object: deployment.yaml  
    assertions:  
    - violations: yes  
```

--------------------------------

### List installed policies

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

List policies currently installed in the cluster in table or JSON format.

```bash
# Table output (default)
gator policy list

# JSON output
gator policy list --output=json
```

--------------------------------

### View Aggregated Kubernetes Event Example

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/customize-startup

Example of an aggregated Kubernetes event output when multiple violations occur within a short interval.

```text
39s         Warning   FailedAdmission   namespace/test      (combined from similar events):  Admission webhook "validation.gatekeeper.sh" denied request, Resource Namespace: , Constraint: ns-must-have-gk, Message: you must provide labels: {"gatekeeper"}
```

--------------------------------

### Install Constraint via kubectl

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/howto

Command to apply a Constraint from a remote URL.

```bash
kubectl apply -f https://raw.githubusercontent.com/open-policy-agent/gatekeeper/master/demo/basic/constraints/all_ns_must_have_gatekeeper.yaml  
```

--------------------------------

### Define resources for expansion

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example manifest containing an ExpansionTemplate, a Deployment, an Assign mutation, and a Namespace definition.

```yaml
apiVersion: expansion.gatekeeper.sh/v1alpha1  
kind: ExpansionTemplate  
metadata:  
  name: expand-deployments  
spec:  
  applyTo:  
  - groups: [ "apps" ]  
    kinds: [ "Deployment" ]  
    versions: [ "v1" ]  
  templateSource: "spec.template"  
  generatedGVK:  
    kind: "Pod"  
    group: ""  
    version: "v1"  
---
apiVersion: apps/v1  
kind: Deployment  
metadata:  
  name: nginx-deployment  
  namespace: my-ns  
  labels:  
    app: nginx  
spec:  
  replicas: 3  
  selector:  
    matchLabels:  
      app: nginx  
  template:  
    metadata:  
      labels:  
        app: nginx  
    spec:  
      containers:  
      - name: nginx  
        image: nginx:1.14.2  
        ports:  
        - containerPort: 80  
        args:  
        - "/bin/sh"  
---
apiVersion: mutations.gatekeeper.sh/v1alpha1  
kind: Assign  
metadata:  
  name: always-pull-image  
spec:  
  applyTo:  
  - groups: [ "" ]  
    kinds: [ "Pod" ]  
    versions: [ "v1" ]  
  location: "spec.containers[name: *].imagePullPolicy"  
  parameters:  
    assign:  
      value: "Always"  
  match:  
    source: "Generated"  
    scope: Namespaced  
    kinds:  
    - apiGroups: [ ]  
      kinds: [ ]  
    namespaceSelector:  
      matchExpressions:  
        - key: admission.gatekeeper.sh/ignore  
          operator: DoesNotExist  
---
# notice this file is providing the non default namespace `my-ns`  
apiVersion: v1  
kind: Namespace  
metadata:  
  name: my-ns
```

--------------------------------

### Test Manifests with Gator

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Examples of testing manifests against policies using various input methods.

```bash
cat my-manifest.yaml | gator test --filename=template-and-constraints/
```

```bash
gator test -f=my-manifest.yaml -f=templates-and-constraints/
```

```bash
cat my-manifest.yaml | gator test --image=localhost:5000/gator/template-library:v1 \
  --image=localhost:5000/gator/constraints:v1
```

--------------------------------

### Running gator sync test with file inputs

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example command usage specifying multiple files and directories for validation.

```bash
gator sync test --filename="template.yaml" –-filename="syncsets/" --filename="manifest.yaml"
```

--------------------------------

### View make tilt output

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Example output showing the build process and container execution steps triggered by make tilt.

```bash
make tilt  
docker build . \
        -t gatekeeper-tooling \
        -f build/tooling/Dockerfile  
[+] Building 1.5s (10/10) FINISHED  
 => [internal] load build definition from Dockerfile                                                                                                                     0.2s  
 => => transferring dockerfile: 35B                                                                                                                                      0.1s  
 => [internal] load .dockerignore                                                                                                                                        0.2s  
 => => transferring context: 34B                                                                                                                                         0.0s  
 => [internal] load metadata for docker.io/library/golang:1.17                                                                                                           1.0s  
 => [auth] library/golang:pull token for registry-1.docker.io                                                                                                            0.0s  
 => [1/5] FROM docker.io/library/golang:1.17@sha256:bd9823cdad5700fb4abe983854488749421d5b4fc84154c30dae474100468b85                                                     0.0s  
 => CACHED [2/5] RUN GO111MODULE=on go install sigs.k8s.io/controller-tools/cmd/controller-gen@v0.8.0                                                                    0.0s  
 => CACHED [3/5] RUN GO111MODULE=on go install k8s.io/code-generator/cmd/conversion-gen@release-1.22                                                                     0.0s  
 => CACHED [4/5] RUN mkdir /gatekeeper                                                                                                                                   0.0s  
 => CACHED [5/5] WORKDIR /gatekeeper                                                                                                                                     0.0s  
 => exporting to image                                                                                                                                                   0.2s  
 => => exporting layers                                                                                                                                                  0.0s  
 => => writing image sha256:7d2fecb230986ffdd78932ad8ff13aa0968c9a9a98bec2fe8ecb21c6e683c730                                                                             0.0s  
 => => naming to docker.io/library/gatekeeper-tooling                                                                                                                    0.0s  
docker run -v /workspaces/gatekeeper:/gatekeeper gatekeeper-tooling controller-gen object:headerFile=./hack/boilerplate.go.txt paths="./apis/..." paths="./pkg/..."  
docker run -v /workspaces/gatekeeper:/gatekeeper gatekeeper-tooling conversion-gen \
        --output-base=/gatekeeper \
        --input-dirs=./apis/mutations/v1beta1,./apis/mutations/v1alpha1 \
        --go-header-file=./hack/boilerplate.go.txt \
        --output-file-base=zz_generated.conversion
```

--------------------------------

### Upgrade installed policies

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Upgrade specific policies or all installed policies, with an option to preview changes.

```bash
# Upgrade a specific policy
gator policy upgrade k8srequiredlabels

# Upgrade all installed policies
gator policy upgrade --all

# Preview upgrades
gator policy upgrade --all --dry-run
```

--------------------------------

### Illustrate Location Parsing

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/mutation

Example YAML structure demonstrating how the location path maps to resource elements.

```yaml
spec:  
  containers:  
  - name: foo  
    imagePullPolicy:  
```

--------------------------------

### Install a ConstraintTemplate via kubectl

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/howto

Applies a remote ConstraintTemplate manifest to the cluster.

```bash
kubectl apply -f https://raw.githubusercontent.com/open-policy-agent/gatekeeper/master/demo/basic/templates/k8srequiredlabels_template.yaml  
```

--------------------------------

### Mutated Object Example

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example of the resulting object after applying external data mutation.

```yaml
...  
metadata:  
  annotations:  
    owner: admin@example.com  
...
```

--------------------------------

### Benchmark Output Example

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/help

Sample output generated by benchstat after running performance benchmarks on a pull request.

```text
name                                              old time/op  new time/op  delta  
pkg:github.com/open-policy-agent/gatekeeper/v3/pkg/mutation goos:linux goarch:amd64  
System_Mutate                                     1.48µs ± 5%  1.50µs ± 4%    ~     (p=0.468 n=10+10)  
pkg:github.com/open-policy-agent/gatekeeper/v3/pkg/mutation/mutators/assign goos:linux goarch:amd64  
AssignMutator_Mutate/always_mutate_1-depth         235ns ± 5%   234ns ± 5%    ~     (p=0.726 n=10+10)  
AssignMutator_Mutate/always_mutate_2-depth         287ns ± 6%   279ns ± 5%    ~     (p=0.190 n=10+10)  
AssignMutator_Mutate/always_mutate_5-depth         420ns ± 2%   416ns ± 3%    ~     (p=0.297 n=9+9)  
AssignMutator_Mutate/always_mutate_10-depth        556ns ± 4%   570ns ± 6%    ~     (p=0.123 n=10+10)  
AssignMutator_Mutate/always_mutate_20-depth        977ns ± 3%   992ns ± 2%    ~     (p=0.063 n=10+10)  
AssignMutator_Mutate/never_mutate_1-depth          196ns ± 4%   197ns ± 6%    ~     (p=0.724 n=10+10)  
AssignMutator_Mutate/never_mutate_2-depth          221ns ± 4%   222ns ± 4%    ~     (p=0.971 n=10+10)  
AssignMutator_Mutate/never_mutate_5-depth          294ns ± 4%   296ns ± 4%    ~     (p=0.436 n=10+10)  
AssignMutator_Mutate/never_mutate_10-depth         424ns ± 2%   425ns ± 3%    ~     (p=0.905 n=9+10)  
AssignMutator_Mutate/never_mutate_20-depth         682ns ± 3%   680ns ± 5%    ~     (p=0.859 n=9+10)  
pkg:github.com/open-policy-agent/gatekeeper/v3/pkg/mutation/mutators/assignimage goos:linux goarch:amd64  
AssignImageMutator_Mutate/always_mutate_1-depth    579ns ± 7%   573ns ± 3%    ~     (p=0.650 n=9+9)  
AssignImageMutator_Mutate/always_mutate_2-depth    625ns ± 5%   627ns ± 2%    ~     (p=0.536 n=10+9)  
AssignImageMutator_Mutate/always_mutate_5-depth    758ns ± 5%   768ns ± 6%    ~     (p=0.631 n=10+10)  
AssignImageMutator_Mutate/always_mutate_10-depth  1.06µs ± 8%  1.08µs ± 5%    ~     (p=0.143 n=10+10)  
AssignImageMutator_Mutate/always_mutate_20-depth  1.38µs ± 3%  1.42µs ± 3%  +2.80%  (p=0.003 n=9+10)  
AssignImageMutator_Mutate/never_mutate_1-depth     237ns ± 3%   233ns ± 3%    ~     (p=0.107 n=10+9)  
AssignImageMutator_Mutate/never_mutate_2-depth     266ns ± 4%   266ns ± 3%    ~     (p=1.000 n=10+10)  
AssignImageMutator_Mutate/never_mutate_5-depth     336ns ± 6%   342ns ± 2%  +1.85%  (p=0.037 n=10+9)  
AssignImageMutator_Mutate/never_mutate_10-depth    463ns ± 3%   479ns ± 5%  +3.53%  (p=0.013 n=9+10)  
AssignImageMutator_Mutate/never_mutate_20-depth    727ns ± 3%   727ns ± 2%    ~     (p=0.897 n=10+8)  
...
```

--------------------------------

### Define Connection Custom Resource

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export-driver

Example YAML configuration to establish a connection to a specific backend driver.

```yaml
apiVersion: connection.gatekeeper.sh/v1alpha1  
kind: Connection  
metadata:  
  name: audit-connection  
  namespace: gatekeeper-system  
spec:  
  driver: "foo"  
  config:  
    key: value  
```

--------------------------------

### Install Gatekeeper with Helm for Disk Export

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export

Helm command to install Gatekeeper with violation export enabled and disk backend configured.

```bash
helm upgrade --install gatekeeper gatekeeper/gatekeeper --namespace gatekeeper-system \
--set enableViolationExport=true \
--set audit.connection=audit-connection \
--set audit.channel=audit-channel \
--set audit.exportConnection.path=tmp/violations/topics \
--set audit.exportConnection.maxAuditResults=3 \
--set exportBackend=disk \

```

--------------------------------

### Running gator sync test with OCI artifacts

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example command usage combining a local configuration file with an OCI artifact containing templates.

```bash
gator sync test --filename="config.yaml" --image=localhost:5000/gator/template-library:v1
```

--------------------------------

### Enable TLS in Go Server

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example of enabling TLS in a Go HTTP server using the generated certificate and key.

```go
server.ListenAndServeTLS("/etc/ssl/certs/server.crt", "/etc/ssl/certs/server.key")  
```

--------------------------------

### Deploy Gatekeeper via Helm

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/install

Installs Gatekeeper using the official Helm chart.

```bash
helm repo add gatekeeper https://open-policy-agent.github.io/gatekeeper/charts  
helm install gatekeeper/gatekeeper --name-template=gatekeeper --namespace gatekeeper-system --create-namespace  

```

--------------------------------

### Admission Control Configuration

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example configuration file for the Kubernetes API server to enable webhook authentication.

```yaml
apiVersion: apiserver.config.k8s.io/v1  
kind: AdmissionConfiguration  
plugins:  
- name: ValidatingAdmissionWebhook  
  configuration:  
    apiVersion: apiserver.config.k8s.io/v1  
    kind: WebhookAdmissionConfiguration  
    kubeConfigFile: "<path-to-kubeconfig-file>"  
- name: MutatingAdmissionWebhook  
  configuration:  
    apiVersion: apiserver.config.k8s.io/v1  
    kind: WebhookAdmissionConfiguration  
    kubeConfigFile: "<path-to-kubeconfig-file>"  
```

--------------------------------

### Gator verify test configuration

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example configuration for a gator test case using an AdmissionReview object.

```yaml
  - name: both-disallowed  
    object: path/to/test_admission_review.yaml  
    assertions:  
    - violations: 1  
```

--------------------------------

### Create a Deployment with Privileged Containers

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/workload-resources

A Deployment example that violates the privileged container constraint but is not blocked at the Deployment level.

```yaml
apiVersion: apps/v1  
kind: Deployment  
metadata:  
  labels:  
    app: i-wont-be-blocked  
  name: i-wont-be-blocked  
spec:  
  replicas: 1  
  selector:  
    matchLabels:  
      app: i-wont-be-blocked  
  template:  
    metadata:  
      labels:  
        app: i-wont-be-blocked  
    spec:  
      containers:  
      - image: nginx  
        name: nginx  
        securityContext:  
          privileged: true  
```

--------------------------------

### Rego Policy for ConstraintTemplate

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/howto

Example Rego code snippet showing how to access parameters via input.parameters.

```rego
      rego: |  
        package k8srequiredlabels  
  
        violation[{"msg": msg, "details": {"missing_labels": missing}}] {  
          provided := {label | input.review.object.metadata.labels[label]}  
          required := {label | label := input.parameters.labels[_]}  
          missing := required - provided  
          count(missing) > 0  
          msg := sprintf("you must provide labels: %v", [missing])  
        }  
```

--------------------------------

### Grant Cluster Admin Permissions

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/install

Required for installation methods to ensure sufficient privileges.

```bash
  kubectl create clusterrolebinding cluster-admin-binding \
    --clusterrole cluster-admin \
    --user <YOUR USER NAME>  

```

--------------------------------

### Define Provider Custom Resource

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example configuration for the Provider custom resource including the caBundle.

```yaml
apiVersion: externaldata.gatekeeper.sh/v1beta1  
kind: Provider  
metadata:  
  name: my-provider  
spec:  
  url: https://<service-name>.<namespace>:<port>/<endpoint> # URL to the external data source (e.g., https://my-provider.my-namespace:8090/validate)  
  timeout: <timeout> # timeout value in seconds (e.g., 1). this is the timeout on the Provider custom resource, not the provider implementation.  
  caBundle: <encoded-ca-certificate> # base64 encoded CA certificate.  
```

--------------------------------

### Example unfulfilled requirements output

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

The error output format displayed to stderr when sync requirements are not met.

```text
the following requirements were not met:
templatename1:
- extensions/v1beta1:Ingress
- networking.k8s.io/v1beta1:Ingress OR networking.k8s.io/v1:Ingress
templatename2:
- apps/v1:Deployment
templatename3:
- /v1:Service
```

--------------------------------

### View Connection status

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export

Example of the status sub-resource for a Connection, showing pod-specific connection state and error details.

```yaml
apiVersion: connection.gatekeeper.sh/v1alpha1  
kind: Connection  
metadata:  
  name: audit-connection  
  namespace: gatekeeper-system  
spec:  
  driver: "dapr"  
  config:  
    component: "pubsub"  
status:  
  byPod:  
    ID: "pod-id"  
    ConnectionUID: "connection-id"  
    Active: {true | false}  
    Errors:  
      - Type: UpsertConnection  
        Message: "Error message"  
      - Type: Publish  
        Message: "Error message"  
```

--------------------------------

### KubeConfig File for Webhook

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example KubeConfig file structure required for the API server to communicate with the webhook service.

```yaml
apiVersion: v1  
clusters:  
- cluster:  
    certificate-authority-data: <myCA.crt> # same value as provided in gatekeeper webhook secret's clientca.crt  
    server: https://<gatekeeper-webhook-service-name>.<gatekeeper-namespace>.svc:443  
  name: <cluster-name>  
contexts:  
- context:  
    cluster: <cluster-name>  
    user: api-server  
  name: <context-name>  
current-context: <context-name>  
kind: Config  
users:  
- name: api-server  
  user:  
    client-certificate-data: <apiserver-client.crt>  
    client-key-data: <apiserver-client.key>  
```

--------------------------------

### Setup Gatekeeper Namespace and Dapr Pubsub

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export

Creates the required namespace, migrates the Redis secret, and applies the Dapr pubsub component configuration.

```bash
kubectl create namespace gatekeeper-system  
kubectl get secret redis --namespace=default -o yaml | sed 's/namespace: .*/namespace: gatekeeper-system/' | kubectl apply -f -  
kubectl apply -f - <<EOF  
apiVersion: dapr.io/v1alpha1  
kind: Component  
metadata:  
  name: pubsub  
  namespace: gatekeeper-system  
spec:  
  type: pubsub.redis  
  version: v1  
  metadata:  
  - name: redisHost  
    value: redis-master.default.svc.cluster.local:6379  
  - name: redisPassword  
    secretKeyRef:  
      name: redis  
      key: redis-password  
EOF  
```

--------------------------------

### Configure Warn Enforcement Action

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/violations

Example of a constraint using the warn enforcement action to provide immediate feedback on violations.

```yaml
apiVersion: constraints.gatekeeper.sh/v1beta1  
kind: K8sAllowedRepos  
metadata:  
  name: repo-is-openpolicyagent  
spec:  
  enforcementAction: warn  
  match:  
    kinds:  
      - apiGroups: [""]  
        kinds: ["Pod"]  
  parameters:  
    repos:  
      - "openpolicyagent"  
```

--------------------------------

### Observe Warn Enforcement Output

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/violations

Example output showing a warning message returned by kubectl when a constraint with warn enforcement is triggered.

```bash
$ kubectl apply pod.yaml  
Warning: [prod-repo-is-openpolicyagent] container <nginx> has an invalid image repo <nginx>, allowed repos are ["openpolicyagent"]  
pod/pause created  
```

--------------------------------

### ConstraintTemplate using Rego v1 syntax

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/constrainttemplates

A complete example of a ConstraintTemplate implementing Rego v1 syntax to enforce required labels on Kubernetes objects.

```yaml
apiVersion: templates.gatekeeper.sh/v1  
kind: ConstraintTemplate  
metadata:  
  name: k8srequiredlabels  
spec:  
  crd:  
    spec:  
      names:  
        kind: K8sRequiredLabels  
      validation:  
        # Schema for the `parameters` field  
        openAPIV3Schema:  
          type: object  
          properties:  
            message:  
              type: string  
            labels:  
              type: array  
              items:  
                type: object  
                properties:  
                  key:  
                    type: string  
                  allowedRegex:  
                    type: string  
  targets:  
    - target: admission.k8s.gatekeeper.sh  
      code:  
        - engine: Rego  
          source:  
            version: "v1"  
            rego: |  
              package k8srequiredlabels  
  
              violation contains   
                {"msg": msg, "details": {"missing_labels": missing}}   
                if {  
                  provided := {label | input.review.object.metadata.labels[label]}  
                  required := {label | label := input.parameters.labels[_]}  
                  missing := required - provided  
                  count(missing) > 0  
                  msg := sprintf("you must provide labels: %v", [missing])  
                }  
```

--------------------------------

### View Admission Review Stats Log

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/metrics

Example JSON log output generated when --log-stats-admission is enabled, showing execution time and constraint counts.

```json
{
  "level": "info",
  "ts": 1683692576.9093642,
  "logger": "webhook",
  "msg": "admission review request stats",
  "hookType": "validation",
  "process": "admission",
  "event_type": "review_response_stats",
  "resource_group": "",
  "resource_api_version": "v1",
  "resource_kind": "Namespace",
  "resource_namespace": "",
  "request_username": "kubernetes-admin",
  "execution_stats": [
    {
      "scope": "template",
      "statsFor": "K8sRequiredLabels",
      "stats": [
        {
          "name": "templateRunTimeNS",
          "value": 762561,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of nanoseconds it took to evaluate all constraints for a template"
        },
        {
          "name": "constraintCount",
          "value": 1,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of constraints that were evaluated for the given constraint kind"
        }
      ],
      "labels": [
        {
          "name": "TracingEnabled",
          "value": false
        },
        {
          "name": "PrintEnabled",
          "value": false
        },
        {
          "name": "target",
          "value": "admission.k8s.gatekeeper.sh"
        }
      ]
    }
  ]
}
```

--------------------------------

### Run the Tilt development environment

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Execute the make command to initiate the Tilt development workflow.

```bash
make tilt
```

--------------------------------

### Apply Sample Policy

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/remote-cluster

Deploys a template and constraint to the remote cluster for testing purposes.

```bash
# Apply a template + constraint to the remote cluster  
kubectl --context <remote> apply -f \  
  https://raw.githubusercontent.com/open-policy-agent/gatekeeper/master/test/bats/tests/remote-cluster/k8srequiredlabels_template.yaml  
kubectl --context <remote> apply -f \  
  https://raw.githubusercontent.com/open-policy-agent/gatekeeper/master/test/bats/tests/remote-cluster/k8srequiredlabels_constraint.yaml  
```

--------------------------------

### Prepare Tilt Development Environment

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Copies generated charts to the Tilt build directory and modifies security contexts to enable live updates.

```bash
mkdir -p .tiltbuild/charts
rm -rf .tiltbuild/charts/gatekeeper
cp -R manifest_staging/charts/gatekeeper .tiltbuild/charts
# disable some configs from the security context so we can perform live update
sed -i "/readOnlyRootFilesystem: true/d" .tiltbuild/charts/gatekeeper/templates/*.yaml
sed -i -e "/run.*: .*/d" .tiltbuild/charts/gatekeeper/templates/*.yaml
tilt up
```

--------------------------------

### Uninstall policies

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Remove installed policies from the cluster, with an option to preview the action.

```bash
# Uninstall a policy
gator policy uninstall k8srequiredlabels

# Preview uninstall
gator policy uninstall k8srequiredlabels --dry-run
```

--------------------------------

### Build Manifests and Helm Charts

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Cleans staging directories and uses Kustomize to build Gatekeeper manifests and Helm charts.

```bash
rm -rf manifest_staging
mkdir -p manifest_staging/deploy/experimental
mkdir -p manifest_staging/charts/gatekeeper
docker run --rm -v /workspaces/gatekeeper:/gatekeeper \
        registry.k8s.io/kustomize/kustomize:v3.8.9 build \
        /gatekeeper/config/default -o /gatekeeper/manifest_staging/deploy/gatekeeper.yaml
docker run --rm -v /workspaces/gatekeeper:/gatekeeper \
        registry.k8s.io/kustomize/kustomize:v3.8.9 build \
        --load_restrictor LoadRestrictionsNone /gatekeeper/cmd/build/helmify | go run cmd/build/helmify/*.go
```

--------------------------------

### Apply Config via kubectl

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/sync

Command to apply a sample configuration file for data replication.

```bash
kubectl apply -f https://raw.githubusercontent.com/open-policy-agent/gatekeeper/master/demo/basic/sync.yaml  
```

--------------------------------

### Declare Case assertions

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Examples of asserting violation expectations in a test case.

```yaml
assertions:  
- violations: yes  
```

```yaml
assertions:  
- violations: no  
```

--------------------------------

### Mutated Object for Assign

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Example of the resulting object after applying an Assign mutation.

```yaml
...  
spec:  
  containers:  
    - name: nginx  
      image: nginx:v1.2.3  
...
```

--------------------------------

### Configure Mutation Operations

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/mutation

Example of restricting a mutation to only trigger during resource creation.

```yaml
applyTo:  
- groups: [""]  
  kinds: ["Pod"]  
  versions: ["v1"]  
  operations: ["CREATE"]  # Only mutate on resource creation
```

--------------------------------

### Define Constraint for Specific Kinds

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/audit

Example of a constraint that restricts auditing to Pod resources.

```yaml
apiVersion: constraints.gatekeeper.sh/v1beta1  
kind: K8sAllowedRepos  
metadata:  
  name: prod-repo-is-openpolicyagent  
spec:  
  match:  
    kinds:  
      - apiGroups: [""]  
        kinds: ["Pod"]  
...  

```

--------------------------------

### AdmissionReview for DELETE operation

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Example of an AdmissionReview object configured for a DELETE operation using oldObject.

```yaml
kind: AdmissionReview  
apiVersion: admission.k8s.io/v1beta1  
request:  
  operation: "DELETE"  
  userInfo:  
    username: "system:foo"  
  oldObject:  
    kind: Pod  
    labels:  
      - app: "bar"  
```

--------------------------------

### Run gator expand with files or images

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Use the --filename flag to specify local manifests or directories, or the --image flag to pull configurations from an OCI artifact.

```bash
gator expand --filename="manifest.yaml" –filename="expansion-policy/"
```

```bash
gator expand --filename="my-deployment.yaml" --image=localhost:5000/gator/expansion-policy:v1
```

--------------------------------

### Implement Driver Connection Structure

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export-driver

Define the connection state and driver name for a new backend implementation.

```go
type Connection struct {  
    // properties needed for individual connection  
}  
  
type Foo struct {  
    openConnections map[string]Connection  
}  
  
const (  
    Name = "foo"  
)  
  
var Connections = &Foo{  
    openConnections: make(map[string]Connection),  
}  
```

--------------------------------

### Configure tilt-settings.json

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Define local deployment settings such as Helm values and trigger modes in the project root.

```json
{
    "helm_values": {
        "controllerManager.metricsPort": 8080,
        "enableExternalData": true
    },
    "trigger_mode": "manual"
}
```

--------------------------------

### Define a K8sRequiredLabels Constraint

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/howto

Example of a Constraint enforcing the presence of a 'gatekeeper' label on all Namespace resources.

```yaml
apiVersion: constraints.gatekeeper.sh/v1beta1  
kind: K8sRequiredLabels  
metadata:  
  name: ns-must-have-gk  
spec:  
  match:  
    kinds:  
      - apiGroups: [""]  
        kinds: ["Namespace"]  
  parameters:  
    labels: ["gatekeeper"]  
```

--------------------------------

### Implement Driver Interface Methods

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export-driver

Required methods for the driver to handle connection lifecycle and message publishing.

```go
func (r *Foo) Publish(ctx context.Context, connectionName string, data interface{}, subject string) error {  
  ...  
}  
  
func (r *Foo) CloseConnection(connectionName string) error {  
  ...  
}  
  
func (r *Foo) UpdateConnection(ctx context.Context, connectionName string, config interface{}) error {  
  ...  
}  
  
func (r *Foo) CreateConnection(ctx context.Context, connectionName string, config interface{}) error {  
  ...  
}  
```

--------------------------------

### Deploy Gatekeeper from Source

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/install

Deploys the built image to the cluster.

```bash
make deploy REPOSITORY=$DESTINATION_GATEKEEPER_IMAGE  

```

--------------------------------

### Audit Log Event

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/audit

Example of a JSON-formatted audit log event emitted by the audit pod.

```json
{
  "level": "info",
  "ts": 1632889070.3075402,
  "logger": "controller",
  "msg": "container <kube-scheduler> has no resource limits",
  "process": "audit",
  "audit_id": "2021-09-29T04:17:47Z",
  "event_type": "violation_audited",
  "constraint_group": "constraints.gatekeeper.sh",
  "constraint_api_version": "v1beta1",
  "constraint_kind": "K8sContainerLimits",
  "constraint_name": "container-must-have-limits",
  "constraint_namespace": "",
  "constraint_action": "deny",
  "constraint_enforcement_actions": [],
  "constraint_annotations": {
    "test-annotation-1": "annotation_1"
  },
  "resource_group": "",
  "resource_api_version": "v1",
  "resource_kind": "Pod",
  "resource_namespace": "kube-system",
  "resource_name": "kube-scheduler-kind-control-plane"
  "resource_labels": {
    "env": "prod",
    "my-app-system": "true"
  }
}
```

--------------------------------

### Uninstall Gatekeeper via Prebuilt Image

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/install

Removes Gatekeeper components installed via manifest URL.

```bash
kubectl delete -f https://raw.githubusercontent.com/open-policy-agent/gatekeeper/v3.23.0/deploy/gatekeeper.yaml  

```

--------------------------------

### Run gator bench

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Execute the benchmark command by specifying the directory or file containing policies and resources.

```bash
gator bench --filename=policies/
```

--------------------------------

### Create a kind cluster with a local registry

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/developers

Provision a Kubernetes cluster with a local registry to optimize image push and pull operations.

```bash
./third_party/github.com/tilt-dev/kind-local/kind-with-registry.sh
```

--------------------------------

### Compare Rego and CEL engines

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Runs benchmarks for both engines and displays a comparison table.

```bash
gator bench --filename=policies/ --engine=all
```

--------------------------------

### Deploy Gatekeeper via Prebuilt Image

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/install

Deploys a specific released version of Gatekeeper using a manifest URL.

```bash
kubectl apply -f https://raw.githubusercontent.com/open-policy-agent/gatekeeper/v3.23.0/deploy/gatekeeper.yaml  

```

--------------------------------

### Valid structural schema

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/constrainttemplates

An example of a valid structural schema for a v1 ConstraintTemplate with the required type declaration.

```yaml
openAPIV3Schema:  
  type: object  
  properties:  
    labels:  
      type: array  
      items:  
        type: string  
```

--------------------------------

### List all constraints via kubectl

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/howto

Use this command to retrieve a list of all constraints currently deployed in the cluster.

```bash
kubectl get constraints
```

--------------------------------

### Invalid non-structural schema

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/constrainttemplates

An example of an invalid schema for a v1 ConstraintTemplate due to the missing type declaration.

```yaml
openAPIV3Schema:  
  # missing type  
  properties:  
    labels:  
      type: array  
      items:  
        type: string  
```

--------------------------------

### Define a v1beta1 ConstraintTemplate

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/constrainttemplates

Example of a ConstraintTemplate using the v1beta1 API version, which does not require a structural schema.

```yaml
apiVersion: templates.gatekeeper.sh/v1beta1  
kind: ConstraintTemplate  
metadata:  
  name: k8srequiredlabels  
spec:  
  crd:  
    spec:  
      names:  
        kind: K8sRequiredLabels  
      validation:  
        # Schema for the `parameters` field  
        openAPIV3Schema:  
          properties:  
            labels:  
              type: array  
              items:  
                type: string  
  targets:  
    - target: admission.k8s.gatekeeper.sh  
      rego: |  
        package k8srequiredlabels  
  
        violation[{"msg": msg, "details": {"missing_labels": missing}}] {  
          provided := {label | input.review.object.metadata.labels[label]}  
          required := {label | label := input.parameters.labels[_]}  
          missing := required - provided  
          count(missing) > 0  
          msg := sprintf("you must provide labels: %v", [missing])  
        }  
```

--------------------------------

### View Constraint with Violations

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/audit

Example of a Constraint resource showing the status field populated with detected violations.

```yaml
apiVersion: constraints.gatekeeper.sh/v1beta1  
kind: K8sRequiredLabels  
metadata:  
  name: ns-must-have-gk  
spec:  
  match:  
    kinds:  
      - apiGroups: [""]  
        kinds: ["Namespace"]  
  parameters:  
    labels: ["gatekeeper"]  
status:  
  auditTimestamp: "2019-05-11T01:46:13Z"  
  enforced: true  
  violations:  
  - enforcementAction: deny  
    group: ""  
    version: v1  
    kind: Namespace  
    message: 'you must provide labels: {"gatekeeper"}'  
    name: default  
  - enforcementAction: deny  
    group: ""  
    version: v1  
    kind: Namespace  
    message: 'you must provide labels: {"gatekeeper"}'  
    name: gatekeeper-system  
  - enforcementAction: deny  
    group: ""  
    version: v1  
    kind: Namespace  
    message: 'you must provide labels: {"gatekeeper"}'  
    name: kube-public  
  - enforcementAction: deny  
    group: ""  
    version: v1  
    kind: Namespace  
    message: 'you must provide labels: {"gatekeeper"}'  
    name: kube-system
```

--------------------------------

### Register New Driver

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export-driver

Add the new driver's connection instance to the supportedDrivers map in system.go.

```go
var supportedDrivers = map[string]driver.Driver{  
    dapr.Name: dapr.Connections,  
  foo.Name: foo.Connections,  
}  
```

--------------------------------

### Generate a policy catalog

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Generate a catalog file from a local gatekeeper-library directory.

```bash
# Generate catalog from gatekeeper-library
gator policy generate-catalog --library-path=/path/to/gatekeeper-library

# Generate with custom output path
gator policy generate-catalog --library-path=. --output=catalog.yaml

# Generate with bundles file
gator policy generate-catalog --library-path=. --bundles=bundles.yaml

# Generate with custom version
gator policy generate-catalog --library-path=. --version=v1.2.0
```

--------------------------------

### AssignMetadata CRD Example

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/mutation

Defines a mutation to add an owner annotation to Pods matching the nginx-* name pattern.

```yaml
apiVersion: mutations.gatekeeper.sh/v1  
kind: AssignMetadata  
metadata:  
  name: demo-annotation-owner  
spec:  
  match:  
    scope: Namespaced  
    name: nginx-*  
    kinds:  
    - apiGroups: ["*"]  
      kinds: ["Pod"]  
  location: "metadata.annotations.owner"  
  parameters:  
    assign:  
      value:  "admin"  
```

--------------------------------

### Opt-out of Audit in Constraints

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/audit

Example of a constraint configured to opt-out of the audit process using scoped enforcement actions.

```yaml
apiVersion: constraints.gatekeeper.sh/v1beta1  
kind: K8sAllowedRepos  
metadata:  
  name: prod-repo-is-openpolicyagent  
spec:  
...  
  enforcementAction: scoped  
  scopedEnforcementActions:  
  - action: warn  
    enforcementPoints:  
    - name: "validation.gatekeeper.sh"  
  - action: deny  
    enforcementPoints:  
    - name: "gator.gatekeeper.sh"  
...  

```

--------------------------------

### View Gatekeeper configuration flags

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/customize-startup

Displays all available configuration flags for a specific Gatekeeper version using the --help flag.

```bash
docker run openpolicyagent/gatekeeper:v3.10.0-beta.0 --help
```

--------------------------------

### Set benchmark comparison thresholds

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

Configures percentage and absolute minimum thresholds for regression detection.

```bash
gator bench --filename=policies/ --compare=baseline.json --threshold=10 --min-threshold=100µs
```

--------------------------------

### Define a Connection resource for Dapr

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/export

Example configuration for a Connection custom resource using the Dapr driver to export violations.

```yaml
apiVersion: connection.gatekeeper.sh/v1alpha1  
kind: Connection  
metadata:  
  name: audit-connection  
  namespace: gatekeeper-system  
spec:  
  driver: "dapr"  
  config:  
    component: "pubsub"  
```

--------------------------------

### Disable external data via Helm

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/externaldata

Use the --set flag during Helm installation to disable external data support.

```bash
helm install gatekeeper/gatekeeper --name-template=gatekeeper --namespace gatekeeper-system --create-namespace \
  --set enableExternalData=false
```

--------------------------------

### Example metadata.gatekeeper.sh/requires-sync-data annotation

Source: https://open-policy-agent.github.io/gatekeeper/website/docs/gator

A JSON object representing a list of requirements for data replication, where each requirement contains interchangeable GVK clauses.

```json
[
  [
    {
      "groups": ["group1", group2"],
      "versions": ["version1", "version2", "version3"],
      "kinds": ["kind1", "kind2"]
    },
    {
      "groups": ["group3", group4"],
      "versions": ["version3", "version4"],
      "kinds": ["kind3", "kind4"]
    }
  ],
  [
    {
      "groups": ["group5"],
      "versions": ["version5"],
      "kinds": ["kind5"]
    }
  ]
]
```