Files
postgrest/nix/tools/monitor_pid.py
T

58 lines
1.4 KiB
Python

# Monitor a process pid with psutil and emits a CSV.
import sys
import time
import psutil
import pandas as pd
KEY = "Elapsed seconds"
BASE_METRICS = ["CPU (%)", "Real (MB)"]
SAMPLE_INTERVAL_SECS = 1
if len(sys.argv) != 2 or not sys.argv[1].isdigit():
sys.exit(f"Usage: {sys.argv[0]} <PID>")
pid = int(sys.argv[1])
try:
proc = psutil.Process(pid)
except psutil.NoSuchProcess:
sys.exit(f"Error: process {pid} not found.")
print(f"Starting monitoring of {pid} pid", file=sys.stderr)
records = []
start = time.time()
# ignore first result as per docs recommendation
# https://psutil.readthedocs.io/en/latest/#psutil.cpu_percent
proc.cpu_percent(None)
while True:
try:
if not proc.is_running():
break
time.sleep(SAMPLE_INTERVAL_SECS)
elapsed_secs = int(time.time() - start)
cpu = proc.cpu_percent(None)
meminfo = proc.memory_info()
bytes_in_MB = 1024**2
rss_mb = meminfo.rss / bytes_in_MB
records.append(
[
str(elapsed_secs),
f"{cpu:.3f}",
f"{rss_mb:.3f}",
]
)
except psutil.NoSuchProcess:
break
end = time.time()
total_time = end - start
print(f"Finished {pid} pid monitoring in {total_time:.3f}", file=sys.stderr)
cols = [KEY] + BASE_METRICS
df = pd.DataFrame(records, columns=cols, dtype=str)
df.to_csv(sys.stdout, index=False)