added: use case - Generate multiple manifests from a single file

README.md

@@ -7,11 +7,11 @@
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](https://github.com/aabouzaid/kustomize-plugin-merger/pulls)
 
 <!-- omit in toc -->
-# Merger
+# 🔀 Merger 🔀
 
 A Kustomize generator plugin to merge YAML files seamlessly for real-world use cases.
 
-**Merger** provides schemaless merge with different merge strategies (StrategicMerge) 🔀.
+**Merger** provides schemaless merge with different merge strategies (StrategicMerge).
 
 
 - [Why](#why)
@@ -106,10 +106,10 @@ This section shows a couple of use cases where Merger can help.
 
 ### 1. Generate multiple manifests from a single base
 
-In this case, you have multiple `CronJobs`, all of them share the same body,
-but each one has a different command or other config.
+In this case, you have multiple `CronJobs`, all of which share the same body,
+but each has a different command or other config.
 
-[Use case full example](./examples/generate-multiple-manifests/README.md).
+[Use case full example](./examples/generate-multiple-manifests-from-single-file/README.md).
 
 ### 2. Merge lists in manifests without schema or a unique identifier
 

examples/generate-multiple-manifests-from-single-file/README.md

@@ -0,0 +1,228 @@
+<!-- omit in toc -->
+# Example - Generate multiple manifests from a single file
+
+- [Use case](#use-case)
+- [Input](#input)
+- [Manifest](#manifest)
+- [Build](#build)
+- [Output](#output)
+
+## Use case
+
+Currently, in Kustomize, you can use a single patch to override multiple resources. However, the vice versa
+doesn't work in the same path (using a single resource as a template and generating multiple resources from it).
+
+## Input
+
+```yaml
+# Base.
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: this-will-be-applied-to-multiple-cronjobs
+spec:
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            image: my-app
+            # The command will be updated via Merger.
+            command: []
+            imagePullPolicy: Always
+          restartPolicy: Never
+          imagePullSecrets:
+          - name: docker-registry
+  # The schedule will be updated via Merger.
+  schedule: ""
+  successfulJobsHistoryLimit: 0
+
+```
+
+```yaml
+# Overlay 01.
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob01
+spec:
+  schedule: '0 1 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob01
+```
+
+```yaml
+# Overlay 02.
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob02
+spec:
+  schedule: '0 2 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob02
+```
+
+```yaml
+# Overlay 03.
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob03
+spec:
+  schedule: '0 3 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob03
+```
+
+## Manifest
+
+```yaml
+# kustomization.yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+generators:
+- merger.yaml
+```
+
+```yaml
+# merger.yaml
+apiVersion: generators.kustomize.aabouzaid.com/v1alpha1
+kind: Merger
+metadata:
+  name: merge
+  annotations:
+    # Containerized KRM function.
+    config.kubernetes.io/function: |
+      container:
+        image: ghcr.io/aabouzaid/kustomize-generator-merger
+        mounts:
+        - type: bind
+          src: ./
+          dst: /mnt
+    # Exec KRM functions.
+    # config.kubernetes.io/function: |
+    # exec:
+    #   path: kustomize-plugin-merger
+spec:
+  resources:
+  - name: my-cronjobs
+    input:
+      method: overlay
+      files:
+        # The same as in the KRM container above.
+        root: /mnt
+        sources:
+        - input/cronjob-01.yaml
+        - input/cronjob-02.yaml
+        - input/cronjob-03.yaml
+        destination: input/cronjob-common.yaml
+    merge:
+      strategy: combine
+    output:
+      format: raw
+```
+
+## Build
+
+```shell
+kustomize build  --enable-alpha-plugins --as-current-user .
+```
+
+## Output
+
+```yaml
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob01
+spec:
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - command:
+            - echo
+            - cronjob01
+            image: my-app
+            imagePullPolicy: Always
+            name: my-app
+          imagePullSecrets:
+          - name: docker-registry
+          restartPolicy: Never
+  schedule: 0 1 * * *
+  successfulJobsHistoryLimit: 0
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob02
+spec:
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - command:
+            - echo
+            - cronjob02
+            image: my-app
+            imagePullPolicy: Always
+            name: my-app
+          imagePullSecrets:
+          - name: docker-registry
+          restartPolicy: Never
+  schedule: 0 2 * * *
+  successfulJobsHistoryLimit: 0
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob03
+spec:
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - command:
+            - echo
+            - cronjob03
+            image: my-app
+            imagePullPolicy: Always
+            name: my-app
+          imagePullSecrets:
+          - name: docker-registry
+          restartPolicy: Never
+  schedule: 0 3 * * *
+  successfulJobsHistoryLimit: 0
+
+```

examples/generate-multiple-manifests-from-single-file/input/cronjob-01.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob01
+spec:
+  schedule: '0 1 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob01

examples/generate-multiple-manifests-from-single-file/input/cronjob-02.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob02
+spec:
+  schedule: '0 2 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob02

examples/generate-multiple-manifests-from-single-file/input/cronjob-03.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: cronjob03
+spec:
+  schedule: '0 3 * * *'
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            command:
+            - echo
+            - cronjob03

examples/generate-multiple-manifests-from-single-file/input/cronjob-common.yaml

@@ -0,0 +1,23 @@
+---
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: this-will-be-applied-to-multiple-cronjobs
+spec:
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: my-app
+            image: my-app
+            # The command will be updated via Merger.
+            command: []
+            imagePullPolicy: Always
+          restartPolicy: Never
+          imagePullSecrets:
+          - name: docker-registry
+  # The schedule will be updated via Merger.
+  schedule: ""
+  successfulJobsHistoryLimit: 0

examples/generate-multiple-manifests-from-single-file/merger.yaml

@@ -0,0 +1,35 @@
+---
+apiVersion: generators.kustomize.aabouzaid.com/v1alpha1
+kind: Merger
+metadata:
+  name: merge
+  annotations:
+    # Containerized KRM function.
+    config.kubernetes.io/function: |
+      container:
+        image: ghcr.io/aabouzaid/kustomize-generator-merger
+        mounts:
+        - type: bind
+          src: ./
+          dst: /mnt
+    # Exec KRM functions.
+    # config.kubernetes.io/function: |
+    # exec:
+    #   path: kustomize-plugin-merger
+spec:
+  resources:
+  - name: my-cronjobs
+    input:
+      method: overlay
+      files:
+        # The same as in the KRM container above.
+        root: /mnt
+        sources:
+        - input/cronjob-01.yaml
+        - input/cronjob-02.yaml
+        - input/cronjob-03.yaml
+        destination: input/cronjob-common.yaml
+    merge:
+      strategy: combine
+    output:
+      format: raw

examples/merge-lists-without-schema/README.md

@@ -1,5 +1,12 @@
+<!-- omit in toc -->
 # Example - Append CustomResources lists without schema
 
+- [Use case](#use-case)
+- [Input](#input)
+- [Manifest](#manifest)
+- [Build](#build)
+- [Output](#output)
+
 ## Use case
 
 Currently, in Kustomize, it's not possible to append CustomResources without providing an Open API schema

examples/merge-lists-without-schema/merger.yaml

@@ -15,7 +15,7 @@ metadata:
     # Exec KRM functions.
     # config.kubernetes.io/function: |
     # exec:
-    #   path: ./kustomize-plugin-merger
+    #   path: kustomize-plugin-merger
 spec:
   resources:
   - name: my-iam-policy