kv_trace_dump

#!/usr/bin/env python3

#   Copyright 2017-Present Couchbase, Inc.
#
#   Use of this software is governed by the Business Source License included
#   in the file licenses/BSL-Couchbase.txt.  As of the Change Date specified
#   in that file, in accordance with the Business Source License, use of this
#   software will be governed by the Apache License, Version 2.0, included in
#   the file licenses/APL2.txt.
#

# Tool to dump a KV-Engine trace file to JSON; which can be viewed
# with Chrome's trace viewer (chrome://tracing).


import argparse
import os
import shutil
import subprocess
import sys

parser = argparse.ArgumentParser(
    description='Dump a KV-Engine trace file as JSON.')
parser.add_argument('--mcctl', help='Path to mcctl binary')
parser.add_argument('-H', '--hostname', required=True,
                    help='host:port to connect to (e.g. localhost:11210)')
parser.add_argument('-u', '--username', required=True, help='Username')
parser.add_argument('-P', '--password', required=False, help='Password')
parser.add_argument('-n', '--norestart', dest='restart', action='store_false',
                    help="Don't restart tracing after dumping the trace file")
parser.add_argument('outfile', type=argparse.FileType('w'))

args = parser.parse_args()

# Locate the mcctl binary
# 1. If the user specified a location, use that one.
mcctl_bin = None
if args.mcctl:
    mcctl_bin = args.mcctl
else:
    # 2. Try the path
    mcctl_bin = shutil.which("mcctl")
    # on windows, the current working directory will always be prepended to
    # the path used by `which()`.
    # If the executable is found in the cwd `which` returns a relative path
    # to it. We don't want that though.
    if not mcctl_bin or os.path.normpath(mcctl_bin) == "mcctl":
        # 3. Look for mcctl in the same directory as the path used to invoke
        # kv_trace_dump, which should be INSTALL_DIR/bin. Note: that
        # location will likely be a symlink on Unix, but we still want that
        # location, not the location the symlink points to.
        script_dir = os.path.dirname(sys.argv[0])
        mcctl_bin = os.path.abspath(os.path.join(script_dir, "mcctl"))

if not os.path.isfile(mcctl_bin):
    print("Error: No mcctl program found at {} - cannot continue.".format(
        mcctl_bin), file=sys.stderr)
    sys.exit(1)

mcctl_args = [mcctl_bin,
              '-h', args.hostname,
              '-u', args.username]

if args.password:
    mcctl_args.extend(['-P', args.password])

subprocess.check_call(mcctl_args + ['set', 'trace.stop'])
uuid = subprocess.check_output(mcctl_args + ['get', 'trace.dump.begin'],
                               universal_newlines=True)
uuid = uuid.strip()

chunk = subprocess.check_output(
    mcctl_args + ['get', 'trace.dump.get?id=' + uuid],
    universal_newlines=True).rstrip()
args.outfile.write(chunk)

# Delete the trace dump on the server
subprocess.check_call(mcctl_args + ['set', 'trace.dump.clear', uuid])

if args.restart:
    subprocess.check_call(mcctl_args + ['set', 'trace.start'])