Maintain a single lossy timeseries (PoC)

ltsdb-json

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+#!/usr/bin/python3
+
+# PoC
+
+# add a new entry and remove a random old entry with a probability
+# depending on the target size
+
+import argparse
+import json
+import random
+import time
+
+ap = argparse.ArgumentParser()
+
+ap.add_argument("--targetsize", type=int, default=1000)
+ap.add_argument("file")
+ap.add_argument("value", type=float)
+
+args = ap.parse_args()
+
+ts = []
+try:
+    with open(args.file) as f:
+        ts = json.load(f)
+except FileNotFoundError as e:
+    pass # Ok, will create
+
+now = time.time()
+ts.append((now, args.value))
+if random.random() > 1 - len(ts) / args.targetsize:
+    i = random.randrange(0, len(ts))
+    ts.pop(i)
+
+with open(args.file, "w") as f:
+    json.dump(ts, f)
+print(len(ts))