source: trunk/bin/sampler

#!/usr/bin/env python3
#-*- mode: Python;-*-

import sys
import os
import time
import random
import tempfile
import argparse
import socket
import json
try:
    import requests
except:
    sys.stderr.write('ERROR: Could not import requests module.  Ensure it is installed.\n')
    sys.stderr.write('       Under Debian, the package name is "python3-requests"\n.')
    sys.exit(1)

VERSION = "{DEVELOPMENT}"
if VERSION == "{DEVELOPMENT}":
    script_dir = '.'
    try:
        script_dir = os.path.dirname(os.path.realpath(__file__))
    except:
        try:
            script_dir = os.path.dirname(os.path.abspath(sys.argv[0]))
        except:
            pass
    sys.path.append("%s/../lib" % script_dir)

from nanownlib import *
from nanownlib.platform import *
from nanownlib.tcpts import *
import nanownlib.storage

parser = argparse.ArgumentParser(
    description="")
parser.add_argument('-c', dest='cases', type=str, default='{"short":10000,"long":13000}',
                    help='JSON representation of echo timing cases.')
parser.add_argument('--no-tcpts', action='store_true', help='Disable TCP timestamp profiling')
parser.add_argument('--no-control', action='store_true', help='Do not collect separate control data.  Instead, synthesize it from test and train data.')
parser.add_argument('session_name', default=None,
                    help='Name for the sampler session (used in output filenames)')
parser.add_argument('sample_count', type=int, default=None,
                    help='Number of samples to collect')
parser.add_argument('host', default=None,
                    help='IP address or host name of server')
parser.add_argument('port', nargs='?', type=int, default=80,
                    help='TCP port number of HTTP service (default: 80)')
options = parser.parse_args()


num_samples = options.sample_count
hostname    = options.host
port        = options.port
protocol    = 'http'

cases = json.loads(options.cases)
db_file = "%s.db" % options.session_name
db = nanownlib.storage.db(db_file)


def extractReportedRuntime(headers, body):
    if body.startswith("waited: "):
        return int(body.split("waited: ")[1], 10)


def sendRequest(data=None):
    method = 'GET'
    path = '/?t=' + data
    url = "%s://%s:%d%s" % (protocol,hostname,port,path)
    headers = {}
    body = (b'')
    req = requests.Request('GET', url).prepare()

    retry = True
    while retry:
        try:
            session = requests.Session()
            response = session.send(req, allow_redirects=False)
            #print("sendRequest:", repr(response.raw._original_response.local_address))
            reported = extractReportedRuntime(response.headers, response.text)
            retry = False
        except Exception as e:
            sys.stderr.write("ERROR: HTTP request problem: %s\n" % repr(e))
            time.sleep(1.0)
            sys.stderr.write("ERROR: retrying...\n")

        
    return {'userspace_rtt':response.elapsed.microseconds*1000,
            'reported':reported,
            'local_port':response.raw._original_response.local_address[1]}


def fetch(probedata, data):
    #   http://docs.python-requests.org/en/latest/api/#requests.Response
    result = sendRequest("%d" % data)
    result.update(probedata)
    
    return result


setCPUAffinity()
time.sleep(0.25) # Give our process a chance to migrate to a different CPU if necessary
setPowersave(False) # XXX: test this to see if it helps
setLowLatency(True) # XXX: test this to see if it helps
tcpts_previous = setTCPTimestamps(True)


#XXX: what about multiple A records?
#     perform this during a script generation step, measuring lowest latency server
#     and hard-coding the IP and host name separately.  However, including all
#     server IPs in comments
host_ip = socket.gethostbyname(hostname) 


meta = {'tcpts_mean':None,'tcpts_stddev':None,'tcpts_slopes':None}
if not options.no_tcpts:
    sys.stderr.write("INFO: Probing target for TCP timestamp precision...\n")
    sniffer_fp = tempfile.NamedTemporaryFile('w+t')
    sniffer = startSniffer(host_ip, port, sniffer_fp.name)
    time.sleep(1.0)
    ports = runTimestampProbes(host_ip, port, hostname, 12)
    time.sleep(1.0)
    stopSniffer(sniffer)
    sniffer_fp.seek(0)
    mean,stddev,slopes = computeTimestampPrecision(sniffer_fp, ports)
    meta = {'tcpts_mean':mean,'tcpts_stddev':stddev,'tcpts_slopes':json.dumps(slopes)}
    
if meta['tcpts_mean'] == None:
    sys.stderr.write("INFO: TCP timestamps not supported.\n")
elif meta['tcpts_stddev'] == None:
    sys.stderr.write("INFO: Not enough TCP timestamp samples.\n")
elif meta['tcpts_stddev']/meta['tcpts_mean'] > 0.05:
    sys.stderr.write("INFO: TCP timestamp precision is inconsistent.\n")
    sys.stderr.write("INFO:     mean=%(tcpts_mean)f,stddev=%(tcpts_stddev)f,samples=%(tcpts_slopes)s\n"
                     % meta)
else:
    sys.stderr.write("INFO: Estimated TCP timestamp precision: %f (stddev: %f, %f%%)\n"
                     % (meta['tcpts_mean'], meta['tcpts_stddev'], 100*meta['tcpts_stddev']/meta['tcpts_mean']))

db.addMeta(meta)


def findNextSampleID(db):
    cursor = db.conn.cursor()
    cursor.execute("SELECT max(sample) FROM probes")
    row = cursor.fetchone()
    if row != None and row[0] != None:
        return row[0]+1

    return 0


def collectSamples(db, sample_type, count, sniffer):
    sniffer.start()

    if not sniffer.is_running():
        sys.stderr.write('ERROR: Sniffer did not start...\n')
        return
        
    sid = findNextSampleID(db)
    for k in range(0,count):
        sample_order = list(cases.items())
        random.shuffle(sample_order)
        if sample_type.endswith('null'):
            for i in range(1,len(sample_order)):
                sample_order[i] = (sample_order[i][0],sample_order[0][1])
            random.shuffle(sample_order)
            
        results = []
        now = int(time.time()*1000000000)
        for i in range(len(sample_order)):
            results.append(fetch({'sample':sid, 'test_case':sample_order[i][0],
                                  'type':sample_type, 'tc_order':i, 'time_of_day':now},
                                 sample_order[i][1]))

        print(results)
        db.addProbes(results)
        db.conn.commit()
        sid += 1

    time.sleep(2.0) # Give sniffer a chance to collect remaining packets
    sniffer.stop()
    #print(sniffer.openPacketLog().read())
    start = time.time()
    associatePackets(sniffer.openPacketLog(), db)
    end = time.time()
    print("associate time:", end-start)
    


if options.no_control:
    num_control = 0
else:
    num_control = int(num_samples*2/5)

num_train = int((num_samples-num_control)/3)
num_test = num_samples-num_train-num_control

sample_types = [('train',num_train),
                ('train_null',num_control),
                ('test',num_test)]

sniffer = snifferProcess(host_ip, port)
for st,count in sample_types:
    collectSamples(db, st,count,sniffer)


#start = time.time()
#report_interval = 20
#next_report = start+report_interval
#        if (time.time() > next_report):
#            reportProgress(db, sample_types, start)
#            next_report += report_interval

    
if options.no_control:
    print("TODO: implement control synthesizing!")

start = time.time()
num_probes = analyzeProbes(db)
end = time.time()
print("analyzed %d probes' packets in: %f" % (num_probes, end-start))


setPowersave(True) # XXX: test this to see if it actually helps
setLowLatency(False) # XXX: test this to see if it actually helps
setTCPTimestamps(tcpts_previous)