feat: Add file extension (read/write)

Signed-off-by: FreehuntX <freehuntx@web.de>

README.md

@@ -21,6 +21,7 @@ All extensions have been vetted and approved by the Tilt team.
 - [`dotenv`](/dotenv): Load environment variables from `.env` or another file.
 - [`earthly`](/earthly): Build container images using [earthly](https://earthly.dev)
 - [`execute_in_pod`](/execute_in_pod): Execute a command on a pod container.
+- [`file`](/file): Read/Write files as text.
 - [`file_sync_only`](/file_sync_only): No-build, no-push, file sync-only development. Useful when you want to live-reload a single config file into an existing public image, like nginx.
 - [`get_obj`](/get_obj): Get object yaml and the container's registry and image from an existing k8s resource such as deployment or statefulset
 - [`git_resource`](/git_resource): Deploy a dockerfile from a remote repository -- or specify the path to a local checkout for local development.

file/README.md

@@ -0,0 +1,38 @@
+# File extension
+
+Author: [FreehuntX](https://github.com/freehuntx)
+
+Helper functions to read/write files.
+
+## Usage
+
+### Read a file as text
+
+```python
+load('ext://file', 'read_file')
+
+text = read_file('/tmp/some_file')
+print(text) # Prints the content of /tmp/some_file
+```
+
+### Write text to a file
+
+```python
+load('ext://file', 'write_file')
+
+write_file('/tmp/some_file', 'This is some text') # Writes to /tmp/some_file
+print(read_file('/tmp/some_file')) # Prints the content
+```
+
+## Functions
+### read_file(path)
+#### Parameters
+* `path` (str) – The path of the file to read
+#### Result
+* (str) - The content of the file 
+### write_file(path, content)
+#### Parameters
+* `path` (str) – The path of the file to read
+* `content` (str) – The text to write to the file
+#### Result
+* (void)

file/Tiltfile

@@ -0,0 +1,21 @@
+def read_file(path):
+  if os.name == "posix": # Linux/Mac implementation
+    return str(local("cat {}".format(path), echo_off=True, quiet=True))
+  elif os.name == "nt": # Windows implementation
+    path = path.replace("/", "\\")
+    return str(local("type {}".format(path), echo_off=True, quiet=True))
+  else:
+    fail("Unknown system architecture: " + os.name)
+
+def write_file(path, content):
+  content = str(content)
+
+  if os.name == "posix": # Linux/Mac implementation
+    local("echo '{}' > {}".format(content, path), echo_off=True, quiet=True)
+  elif os.name == "nt": # Windows implementation
+    path = path.replace("/", "\\")
+    local('type nul > {}'.format(path), echo_off=True, quiet=True)
+    for line in content.splitlines():
+      local('echo {} >> {}'.format(str(line).replace('&', '^&').replace('<', '^<').replace('>', '^>'), path), echo_off=True, quiet=True)
+  else:
+    fail("Unknown system architecture: " + os.name)