Add set-default-labels function

Author: yuwenma

examples/set-default-labels-nested-package/.expected/diff.patch

@@ -0,0 +1,24 @@
+diff --git a/resources.yaml b/resources.yaml
+index 1e641f7..bb4be90 100644
+--- a/resources.yaml
++++ b/resources.yaml
+@@ -2,6 +2,9 @@ apiVersion: v1
+ kind: ConfigMap
+ metadata:
+   name: the-map
++  labels:
++    color: orange
++    fruit: apple
+ data:
+   some-key: some-value
+ ---
+@@ -10,6 +13,9 @@ kind: MyResource
+ metadata:
+   name: the-service
+   namespace: the-namespace
++  labels:
++    color: orange
++    fruit: apple
+ spec:
+   selector:
+     labels:

examples/set-default-labels-nested-package/.krmignore

@@ -0,0 +1 @@
+.expected

examples/set-default-labels-nested-package/Kptfile

@@ -0,0 +1,9 @@
+apiVersion: kpt.dev/v1
+kind: Kptfile
+metadata:
+  name: root-app
+  annotations:
+    config.kubernetes.io/local-config: "true"
+pipeline:
+  mutators:
+    - image: gcr.io/kpt-fn/set-default-labels:unstable

examples/set-default-labels-nested-package/README.md

@@ -0,0 +1,38 @@
+# set-default-labels: Nested Package Example
+
+### Overview
+
+This example shows how to run [`set-default-labels`] in a nested KPT package. 
+
+### Fetch the example package
+
+Get the example package by running the following commands:
+
+```shell
+kpt pkg get https://github.com/GoogleContainerTools/kpt-functions-catalog.git/examples/set-default-labels-nested-package your-app
+```
+
+We use the following `Kptfile` to configure the function.
+
+```yaml
+apiVersion: kpt.dev/v1
+kind: Kptfile
+metadata:
+  name: your-app
+pipeline:
+  mutators:
+    - image: gcr.io/kpt-fn/set-default-labels:unstable
+```
+
+### Function invocation
+
+Invoke the function by running the following commands:
+
+```shell
+$ kpt fn render your-app
+```
+
+### Expected result
+All resources should have `app.kubernetes.io/name: your-app` label added to the meta and label selector fields.
+
+[`set-default-labels`]: https://catalog.kpt.dev/set-labels/v0.1/

examples/set-default-labels-nested-package/app1_ghost/Kptfile

@@ -0,0 +1,8 @@
+apiVersion: kpt.dev/v1
+kind: Kptfile
+metadata:
+  name: app1_ghost
+  annotations:
+    config.kubernetes.io/local-config: "true"
+info:
+  description: sample description

examples/set-default-labels-nested-package/app1_ghost/resources.yaml

@@ -0,0 +1,18 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: ghost
+spec:
+  replicas: 2
+  template:
+    spec:
+      containers:
+        - name: ghost
+          image: ghost:3-alpine
+          ports:
+            - containerPort: 2368
+          env:
+            - name: url
+              value: http://localhost:8080
+            - name: database__connection__database
+              value: ghost

examples/set-default-labels-nested-package/app2_mysql/Kptfile

@@ -0,0 +1,8 @@
+apiVersion: kpt.dev/v1
+kind: Kptfile
+metadata:
+  name: app2_mysql
+  annotations:
+    config.kubernetes.io/local-config: "true"
+info:
+  description: sample description

examples/set-default-labels-nested-package/app2_mysql/README.md

@@ -0,0 +1,21 @@
+# app2
+
+## Description
+sample description
+
+## Usage
+
+### Fetch the package
+`kpt pkg get REPO_URI[.git]/PKG_PATH[@VERSION] app2`
+Details: https://kpt.dev/reference/cli/pkg/get/
+
+### View package content
+`kpt pkg tree app2`
+Details: https://kpt.dev/reference/cli/pkg/tree/
+
+### Apply the package
+```
+kpt live init app2
+kpt live apply app2 --reconcile-timeout=2m --output=table
+```
+Details: https://kpt.dev/reference/cli/live/

examples/set-default-labels-nested-package/app2_mysql/resources.yaml

@@ -0,0 +1,15 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: mysql
+spec:
+  template:
+    spec:
+      containers:
+        - name: mysql
+          image: mysql:5.7
+          ports:
+            - name: mysql
+              containerPort: 3306
+  strategy:
+    type: Recreate

functions/go/Makefile

@@ -37,6 +37,7 @@ FUNCTIONS := \
 	set-enforcement-action \
 	set-image \
 	set-labels \
+	set-default-labels \
 	set-namespace \
 	set-project-id \
 	source-gcloud-config \

functions/go/set-default-labels/README.md

@@ -0,0 +1,54 @@
+# set-default-labels
+
+## Overview
+
+<!--mdtogo:Short-->
+
+The `set-default-labels` function applies KPT label convention to your KPT package.
+
+
+### `app.kubernetes.io/name` 
+
+Running the function can add this label using the value from the root `Kptfile` name.
+
+This convention believes that all KRM resources under the same kpt package should be served for a specific application.
+An application (or KPT package) can be composed by other applications (nested sub KPT packages). 
+So the function can accept multiple Kptfile and use the root Kptfile to set the app name.
+
+<!--mdtogo-->
+
+You can learn more about recommended labels [here][recommended labels].
+
+## Usage
+
+This function should be run in a KPT package. It does not require function config.
+
+### Run the function once
+```bash
+kpt fn eval --image set-default-labels
+```
+
+### Run the function as a Kpt pipeline
+```bash
+# add the function to Kptfile
+kpt fn eval -t mutator -s -i set-default-labels:unstable
+
+# check Kptfile
+cat Kptfile
+
+apiVersion: kpt.dev/v1
+kind: Kptfile
+metadata:
+  name: set-default-label-example
+  annotations:
+    config.kubernetes.io/local-config: "true"
+pipeline:
+  mutators:
+    - image: gcr.io/kpt-fn/set-default-labels:unstable
+
+# run the function in a CI pipeline
+kpt fn render
+```
+<!--mdtogo-->
+
+[recommended labels]: https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/

functions/go/set-default-labels/generated/docs.go

@@ -0,0 +1,32 @@
+module github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-default-labels
+
+go 1.17
+
+require (
+	github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-labels v0.0.0-20220720210558-f05f54028534
+	github.com/GoogleContainerTools/kpt-functions-sdk/go/fn v0.0.0-20220723081830-33aee7fe8a2e
+)
+
+require (
+	github.com/GoogleContainerTools/kpt-functions-sdk/go/api v0.0.0-20220720212527-133180134b93 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-errors/errors v1.4.2 // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.20.0 // indirect
+	github.com/go-openapi/swag v0.21.1 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/gnostic v0.6.9 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/stretchr/testify v1.8.0 // indirect
+	github.com/xlab/treeprint v1.1.0 // indirect
+	google.golang.org/protobuf v1.28.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/klog/v2 v2.70.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20220627174259-011e075b9cb8 // indirect
+	sigs.k8s.io/kustomize/kyaml v0.13.7 // indirect
+)