introduce eden logs command

Summary: Introduces an `eden logs` command to read a large chunk (1M by default) file into a paste. This is also added to the the eden rage report to get more insight into systems in which we cannot log in to view the logs (like laptops).

Reviewed By: kmancini

Differential Revision: D24146812

fbshipit-source-id: 991f1595b974eb01f77e86559a8413b0b09a24a4

eden/fs/cli/main.py

@@ -1742,6 +1742,53 @@ update your shell's working directory."""
         return 0
 
 
+@subcmd("logs", "Gather logs from eden")
+class LogsCmd(Subcmd):
+    def setup_parser(self, parser: argparse.ArgumentParser) -> None:
+        parser.add_argument(
+            "--stdout",
+            action="store_true",
+            help="Print the logs to stdout: ignore reporter.",
+        )
+        parser.add_argument(
+            "--full", action="store_true", help="Gather the full logs from eden"
+        )
+        parser.add_argument(
+            "--size",
+            type=int,
+            default=1000000,
+            help="The amount of the logs we should gather. If --full is passed in,"
+            "we will ignore this value. Default to 1M",
+        )
+
+    def run(self, args: argparse.Namespace) -> int:
+        instance = get_eden_instance(args)
+        eden_log_path = instance.get_log_path()
+        if not eden_log_path.exists():
+            print(f"No log file found at {eden_log_path}", file=sys.stderr)
+            return 1
+
+        # For ease of use, just use the same rage reporter
+        rage_processor = instance.get_config_value("rage.reporter", default="")
+
+        proc: Optional[subprocess.Popen] = None
+        if rage_processor and not args.stdout:
+            proc = subprocess.Popen(shlex.split(rage_processor), stdin=subprocess.PIPE)
+            sink = proc.stdin
+        else:
+            proc = None
+            sink = sys.stdout.buffer
+
+        # pyre-fixme[6]: Expected `IO[bytes]` for 2nd param but got
+        #  `Optional[typing.IO[typing.Any]]`.
+        rage_mod.print_log_file(eden_log_path, sink, args.full, args.size)
+        if proc:
+            # pyre-fixme[16]: `Optional` has no attribute `close`.
+            sink.close()
+            proc.wait()
+        return 0
+
+
 @subcmd("rage", "Gather diagnostic information about eden")
 class RageCmd(Subcmd):
     def setup_parser(self, parser: argparse.ArgumentParser) -> None:

eden/fs/cli/rage.py

@@ -9,6 +9,8 @@ import getpass
 import io
 import os.path
 import platform
+import re
+import shlex
 import socket
 import subprocess
 import sys
@@ -53,6 +55,9 @@ def print_diagnostic_info(instance: EdenInstance, out: IO[bytes]) -> None:
         # TODO(zeyi): fix `eden doctor` on Windows
         print_eden_doctor_report(instance, out)
 
+    processor = instance.get_config_value("rage.reporter", default="")
+    if processor:
+        print_expanded_log_file(instance.get_log_path(), processor, out)
     print_tail_of_log_file(instance.get_log_path(), out)
     print_running_eden_process(out)
 
@@ -124,6 +129,65 @@ def print_eden_doctor_report(instance: EdenInstance, out: IO[bytes]) -> None:
         out.write(traceback.format_exc().encode("utf-8") + b"\n")
 
 
+def read_chunk(logfile: IO[bytes]):
+    CHUNK_SIZE = 20 * 1024
+    while True:
+        data = logfile.read(CHUNK_SIZE)
+        if not data:
+            break
+        yield data
+
+
+def print_log_file(
+    path: Path, out: IO[bytes], whole_file: bool, size: int = 1000000
+) -> None:
+    try:
+        with path.open("rb") as logfile:
+            if not whole_file:
+                LOG_AMOUNT = size
+                size = logfile.seek(0, io.SEEK_END)
+                logfile.seek(max(0, size - LOG_AMOUNT), io.SEEK_SET)
+            for data in read_chunk(logfile):
+                out.write(data)
+    except Exception as e:
+        out.write(b"Error reading the log file: %s\n" % str(e).encode())
+
+
+def print_expanded_log_file(path: Path, processor: str, out: IO[bytes]) -> None:
+    try:
+        proc = subprocess.Popen(
+            shlex.split(processor), stdin=subprocess.PIPE, stdout=subprocess.PIPE
+        )
+        sink = proc.stdin
+        output = proc.stdout
+
+        # pyre-fixme[6]: Expected `IO[bytes]` for 2nd param but got
+        #  `Optional[typing.IO[typing.Any]]`.
+        print_log_file(path, sink, whole_file=False)
+
+        # pyre-fixme[16]: `Optional` has no attribute `close`.
+        sink.close()
+
+        # pyre-fixme[16]: `Optional` has no attribute `read`.
+        stdout = output.read().decode("utf-8")
+
+        output.close()
+        proc.wait()
+
+        # Expected output to be in form "<str0>\n<str1>: <str2>\n"
+        # and we want str1
+        pattern = re.compile("^.*\\n[a-zA-Z0-9_.-]*: .*\\n$")
+        match = pattern.match(stdout)
+
+        if not match:
+            out.write(b"Verbose Eden logs: %s\n" % stdout.encode())
+        else:
+            paste, _ = stdout.split("\n")[1].split(": ")
+            out.write(b"Verbose Eden logs: %s\n" % paste.encode())
+    except Exception as e:
+        out.write(b"Error generating expanded Eden logs: %s\n" % str(e).encode())
+
+
 def print_tail_of_log_file(path: Path, out: IO[bytes]) -> None:
     try:
         out.write(b"\nMost recent Eden logs:\n")