Add support for generating files from command output

.github/workflows/build_and_test.yaml

@@ -97,6 +97,8 @@ jobs:
         kubectl cp sidecar:/tmp/absolute/absolute.txt /tmp/absolute.txt
         kubectl cp sidecar:/tmp/relative/relative.txt /tmp/relative.txt
         kubectl cp sidecar:/tmp/500.txt /tmp/500.txt || true
+        kubectl cp sidecar:/tmp/command-output.txt /tmp/command-output.txt
+        kubectl cp sidecar:/tmp/hostname.txt /tmp/hostname.txt
 
         echo "Downloading resource files from sidecar-5xx..."
         kubectl cp sidecar-5xx:/tmp-5xx/hello.world /tmp/5xx/hello.world
@@ -119,6 +121,8 @@ jobs:
           echo -n "This absolutely exists" | diff - /tmp/absolute.txt &&
           echo -n "This relatively exists" | diff - /tmp/relative.txt &&
           [ ! -f /tmp/500.txt ] && echo "No 5xx file created" &&
+          echo -n "This generated by script" | diff - /tmp/command-output.txt &&
+          echo "sidecar" | diff - /tmp/hostname.txt &&
           ls /tmp/script_result &&
           echo -n "Hello World!" | diff - /tmp/5xx/hello.world &&
           diff test/kubelogo.png /tmp/5xx/cm-kubelogo.png &&

README.md

@@ -33,7 +33,7 @@ Both are identical multi-arch images built for `amd64`, `arm64`, `arm/v7`, `ppc6
 - Update/Delete on change of configmap or secret
 - Enforce unique filenames
 
-# Usage 
+# Usage
 
 Example for a simple deployment can be found in [`example.yaml`](./example.yaml). Depending on the cluster setup you have to grant yourself admin rights first:
 ```shell
@@ -48,6 +48,7 @@ metadata:
 ```
 
 If the filename ends with `.url` suffix, the content will be processed as a URL which the target file contents will be downloaded from.
+If the filename ends with `.command` suffix, the content will be processed as a shell command which will be executed. Stdout of the command will be stored in the file.
 
 ## Configuration Environment Variables
 

example.yaml

@@ -71,6 +71,19 @@ data:
   # base64 encoded: my super cool \n multiline \ secret
   secret.world: bXkgc3VwZXIgY29vbAptdWx0aWxpbmUKc2VjcmV0
 ---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: output-of-command
+  labels:
+    findme: "yup"
+data:
+  rand.sh: |
+    #!/bin/sh
+    dd if=/dev/random bs=4 count=1 | hexdump -v -e '/1 "%02X"'
+  random.txt.command: '/tmp/rand.sh'
+  hostname.txt.command: '/bin/hostname'
+---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRole
 metadata:
@@ -97,4 +110,3 @@ subjects:
 - kind: ServiceAccount
   name: sample-acc
   namespace: default
-

src/helpers.py

@@ -158,11 +158,13 @@ def unique_filename(filename, namespace, resource, resource_name):
 def execute(script_path):
     logger.debug(f"Executing script from {script_path}")
     try:
-        result = subprocess.run(["sh", script_path],
+        result = subprocess.run(script_path, shell=True,
                                 capture_output=True,
-                                check=True)
+                                check=True,
+                                text=True)
         logger.debug(f"Script stdout: {result.stdout}")
         logger.debug(f"Script stderr: {result.stderr}")
         logger.debug(f"Script exit code: {result.returncode}")
     except subprocess.CalledProcessError as e:
         logger.error(f"Script failed with error: {e}")
+    return result

src/resources.py

@@ -43,15 +43,18 @@ def signal_handler(signum, frame):
 signal.signal(signal.SIGTERM, signal_handler)
 
 
-def _get_file_data_and_name(full_filename, content, enable_5xx, content_type=CONTENT_TYPE_TEXT):
+def _get_file_data_and_name(full_filename, content, enable_5xx, content_type=CONTENT_TYPE_TEXT, remove=False):
     if content_type == CONTENT_TYPE_BASE64_BINARY:
         file_data = base64.b64decode(content)
     else:
         file_data = content
 
-    if full_filename.endswith(".url"):
+    if full_filename.endswith(".url") and not remove:
         filename = full_filename[:-4]
         file_data = request(file_data, "GET", enable_5xx).text
+    elif full_filename.endswith(".command") and not remove:
+        filename = full_filename[:-8]
+        file_data = execute(file_data).stdout
     else:
         filename = full_filename
 
@@ -187,7 +190,8 @@ def _update_file(data_key, data_content, dest_folder, metadata, resource,
         filename, file_data = _get_file_data_and_name(data_key,
                                                       data_content,
                                                       enable_5xx,
-                                                      content_type)
+                                                      content_type,
+                                                      remove)
         if unique_filenames:
             filename = unique_filename(filename=filename,
                                        namespace=metadata.namespace,

test/resources/resources.yaml

@@ -51,3 +51,16 @@ metadata:
     findme: "yup"
 data:
   500.txt.url: "http://dummy-server/500"
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: command-configmap
+  labels:
+    findme: "yup"
+data:
+  script.sh: |-
+    #!/bin/sh
+    echo -n "This generated by script"
+  command-output.txt.command: '/tmp/script.sh'
+  hostname.txt.command: '/bin/hostname'