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[PULL 03/14] simpletrace: improve parsing of sys.argv; fix files never c
From: |
Stefan Hajnoczi |
Subject: |
[PULL 03/14] simpletrace: improve parsing of sys.argv; fix files never closed. |
Date: |
Thu, 28 Sep 2023 09:43:56 -0400 |
From: Mads Ynddal <m.ynddal@samsung.com>
The arguments extracted from `sys.argv` named and unpacked to make it
clear what the arguments are and what they're used for.
The two input files were opened, but never explicitly closed. File usage
changed to use `with` statement to take care of this. At the same time,
ownership of the file-object is moved up to `run` function. Added option
to process to support file-like objects.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Mads Ynddal <m.ynddal@samsung.com>
Message-id: 20230926103436.25700-4-mads@ynddal.dk
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
scripts/simpletrace.py | 48 +++++++++++++++++++++++++++++-------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py
index 5c230a1b74..283b5918a1 100755
--- a/scripts/simpletrace.py
+++ b/scripts/simpletrace.py
@@ -9,6 +9,7 @@
#
# For help see docs/devel/tracing.rst
+import sys
import struct
import inspect
from tracetool import read_events, Event
@@ -51,7 +52,6 @@ def get_record(edict, idtoname, rechdr, fobj):
try:
event = edict[name]
except KeyError as e:
- import sys
sys.stderr.write('%s event is logged but is not declared ' \
'in the trace events file, try using ' \
'trace-events-all instead.\n' % str(e))
@@ -172,11 +172,28 @@ def end(self):
pass
def process(events, log, analyzer, read_header=True):
- """Invoke an analyzer on each event in a log."""
+ """Invoke an analyzer on each event in a log.
+ Args:
+ events (file-object or list or str): events list or file-like object
or file path as str to read event data from
+ log (file-object or str): file-like object or file path as str to read
log data from
+ analyzer (Analyzer): Instance of Analyzer to interpret the event data
+ read_header (bool, optional): Whether to read header data from the log
data. Defaults to True.
+ """
+
if isinstance(events, str):
- events = read_events(open(events, 'r'), events)
+ with open(events, 'r') as f:
+ events_list = read_events(f, events)
+ elif isinstance(events, list):
+ # Treat as a list of events already produced by tracetool.read_events
+ events_list = events
+ else:
+ # Treat as an already opened file-object
+ events_list = read_events(events, events.name)
+
+ close_log = False
if isinstance(log, str):
log = open(log, 'rb')
+ close_log = True
if read_header:
read_trace_header(log)
@@ -187,12 +204,12 @@ def process(events, log, analyzer, read_header=True):
edict = {"dropped": dropped_event}
idtoname = {dropped_event_id: "dropped"}
- for event in events:
+ for event in events_list:
edict[event.name] = event
# If there is no header assume event ID mapping matches events list
if not read_header:
- for event_id, event in enumerate(events):
+ for event_id, event in enumerate(events_list):
idtoname[event_id] = event.name
def build_fn(analyzer, event):
@@ -225,24 +242,25 @@ def build_fn(analyzer, event):
fn_cache[event_num](event, rec)
analyzer.end()
+ if close_log:
+ log.close()
+
def run(analyzer):
"""Execute an analyzer on a trace file given on the command-line.
This function is useful as a driver for simple analysis scripts. More
advanced scripts will want to call process() instead."""
- import sys
- read_header = True
- if len(sys.argv) == 4 and sys.argv[1] == '--no-header':
- read_header = False
- del sys.argv[1]
- elif len(sys.argv) != 3:
- sys.stderr.write('usage: %s [--no-header] <trace-events> ' \
- '<trace-file>\n' % sys.argv[0])
+ try:
+ # NOTE: See built-in `argparse` module for a more robust cli interface
+ *no_header, trace_event_path, trace_file_path = sys.argv[1:]
+ assert no_header == [] or no_header == ['--no-header'], 'Invalid
no-header argument'
+ except (AssertionError, ValueError):
+ sys.stderr.write(f'usage: {sys.argv[0]} [--no-header] <trace-events>
<trace-file>\n')
sys.exit(1)
- events = read_events(open(sys.argv[1], 'r'), sys.argv[1])
- process(events, sys.argv[2], analyzer, read_header=read_header)
+ with open(trace_event_path, 'r') as events_fobj, open(trace_file_path,
'rb') as log_fobj:
+ process(events_fobj, log_fobj, analyzer, read_header=not no_header)
if __name__ == '__main__':
class Formatter(Analyzer):
--
2.41.0
- [PULL 00/14] Tracing patches, Stefan Hajnoczi, 2023/09/28
- [PULL 02/14] simpletrace: annotate magic constants from QEMU code, Stefan Hajnoczi, 2023/09/28
- [PULL 03/14] simpletrace: improve parsing of sys.argv; fix files never closed.,
Stefan Hajnoczi <=
- [PULL 05/14] simpletrace: update code for Python 3.11, Stefan Hajnoczi, 2023/09/28
- [PULL 06/14] simpletrace: improved error handling on struct unpack, Stefan Hajnoczi, 2023/09/28
- [PULL 08/14] simpletrace: made Analyzer into context-manager, Stefan Hajnoczi, 2023/09/28
- [PULL 01/14] simpletrace: add __all__ to define public interface, Stefan Hajnoczi, 2023/09/28
- [PULL 07/14] simpletrace: define exception and add handling, Stefan Hajnoczi, 2023/09/28
- [PULL 11/14] simpletrace: move event processing to Analyzer class, Stefan Hajnoczi, 2023/09/28
- [PULL 10/14] simpletrace: move logic of process into internal function, Stefan Hajnoczi, 2023/09/28
- [PULL 09/14] simpletrace: refactor to separate responsibilities, Stefan Hajnoczi, 2023/09/28
- [PULL 04/14] simpletrace: changed naming of edict and idtoname to improve readability, Stefan Hajnoczi, 2023/09/28
- [PULL 13/14] MAINTAINERS: add maintainer of simpletrace.py, Stefan Hajnoczi, 2023/09/28