Merge pull request #34 from Textualize/pipe

WIP pipe support

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "toolong"
-version = "1.2.2"
+version = "1.3.0"
 description = "A terminal log file viewer / tailer / analyzer"
 authors = ["Will McGugan <will@textualize.io>"]
 license = "MIT"
@@ -13,7 +13,7 @@ documentation = "https://github.com/textualize/toolong"
 [tool.poetry.dependencies]
 python = "^3.8"
 click = "^8.1.7"
-textual = "^0.50.0"
+textual = "^0.52.0"
 typing-extensions = "^4.9.0"
 
 [tool.poetry.group.dev.dependencies]

src/toolong/cli.py

@@ -1,6 +1,9 @@
 from __future__ import annotations
 
 from importlib.metadata import version
+import os
+import sys
+
 import click
 
 from toolong.ui import UI
@@ -19,9 +22,55 @@
 )
 def run(files: list[str], merge: bool, output_merge: str) -> None:
     """View / tail / search log files."""
-    if not files:
+    stdin_tty = sys.__stdin__.isatty()
+    if not files and stdin_tty:
         ctx = click.get_current_context()
         click.echo(ctx.get_help())
         ctx.exit()
-    ui = UI(files, merge=merge, save_merge=output_merge)
-    ui.run()
+    if stdin_tty:
+        try:
+            ui = UI(files, merge=merge, save_merge=output_merge)
+            ui.run()
+        except Exception:
+            pass
+    else:
+        import signal
+        import selectors
+        import subprocess
+        import tempfile
+
+        def request_exit(*args) -> None:
+            """Don't write anything when a signal forces an error."""
+            sys.stderr.write("^C")
+
+        signal.signal(signal.SIGINT, request_exit)
+        signal.signal(signal.SIGTERM, request_exit)
+
+        # Write piped data to a temporary file
+        with tempfile.NamedTemporaryFile(
+            mode="w+b", buffering=0, prefix="tl_"
+        ) as temp_file:
+
+            # Get input directly from /dev/tty to free up stdin
+            with open("/dev/tty", "rb", buffering=0) as tty_stdin:
+                # Launch a new process to render the UI
+                with subprocess.Popen(
+                    [sys.argv[0], temp_file.name],
+                    stdin=tty_stdin,
+                    close_fds=True,
+                    env={**os.environ, "TEXTUAL_ALLOW_SIGNALS": "1"},
+                ) as process:
+
+                    # Current process copies from stdin to the temp file
+                    selector = selectors.SelectSelector()
+                    selector.register(sys.stdin.fileno(), selectors.EVENT_READ)
+
+                    while process.poll() is None:
+                        for _, event in selector.select(0.1):
+                            if process.poll() is not None:
+                                break
+                            if event & selectors.EVENT_READ:
+                                if line := os.read(sys.stdin.fileno(), 1024 * 64):
+                                    temp_file.write(line)
+                                else:
+                                    break