Improve file diff using Facts

Author: jgelens

pyinfra/facts/files.py

@@ -534,3 +534,13 @@ def process(self, output):
         if output and (output[0] == f"{MISSING}{self.path}"):
             return None
         return output
+
+
+class FileContents(FactBase):
+    @override
+    def command(self, path):
+        return make_formatted_string_command( "cat {0}", QuoteString(path))
+
+    @override
+    def process(self, output):
+        return output

pyinfra/operations/files.py

@@ -10,7 +10,7 @@
 import traceback
 from datetime import timedelta
 from fnmatch import fnmatch
-from io import BytesIO, StringIO
+from io import StringIO
 from pathlib import Path
 from typing import IO, Any, Union
 
@@ -45,6 +45,7 @@
     Block,
     Directory,
     File,
+    FileContents,
     FindFiles,
     FindInFile,
     Flags,
@@ -897,6 +898,7 @@ def put(
     if create_remote_dir:
         yield from _create_remote_dir(dest, user, group)
 
+
     # No remote file, always upload and user/group/mode if supplied
     if not remote_file or force:
         yield FileUploadCommand(
@@ -917,11 +919,9 @@ def put(
 
         # Check sha1sum, upload if needed
         if local_sum != remote_sum:
-            current_contents = BytesIO()
-
             # Generate diff when contents change
-            host.get_file(dest, current_contents)
-            current_lines = current_contents.getvalue().decode("utf-8").splitlines(keepends=True)
+            current_contents = host.get_fact(FileContents, path=dest)
+            current_lines = [line + "\n" for line in current_contents]
             logger.info(f"\n    Will modify {click.style(dest, bold=True)}")
 
             with get_file_io(src, "r") as f:

pyinfra/operations/util/files.py

@@ -178,9 +178,7 @@ def adjust_regex(line: str, escape_regex_characters: bool) -> str:
     return match_line
 
 
-def generate_color_diff(
-    current_lines: list[str], desired_lines: list[str]
-) -> Generator[str, None, None]:
+def generate_color_diff(current_lines: list[str], desired_lines: list[str]) -> Generator[str, None, None]:
     def _format_range_unified(start: int, stop: int) -> str:
         beginning = start + 1  # lines start numbering with one
         length = stop - start