Add scripts for PR metrics from github API

pr-metrics/do.sh

@@ -2,7 +2,7 @@
 
 set -eu
 
-for topic in created closed pending lifetime; do
+for topic in created closed pending lifetime backlog; do
     echo "PRs $topic..."
     rm -f prs-${topic}.png prs-${topic}.csv
     ./pr-${topic}.py > prs-${topic}.csv

pr-metrics/pr-backlog.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+# coding: utf-8
+
+"""Produce analysis of PR backlog over time"""
+
+from prs import pr_dates, first, last, quarter
+
+from datetime import datetime, timedelta
+from collections import Counter
+from itertools import chain
+
+import matplotlib.pyplot as plt
+
+new_days = 90
+old_days = 365
+
+new = Counter()
+med = Counter()
+old = Counter()
+
+for beg, end, com in pr_dates():
+    if end is None:
+        tomorrow = datetime.now().date() + timedelta(days=1)
+        n_days = (tomorrow - beg).days
+    else:
+        n_days = (end - beg).days
+    for i in range(n_days):
+        q = quarter(beg + timedelta(days=i))
+        q1 = quarter(beg + timedelta(days=i+1))
+        # Only count on each quarter's last day
+        if q == q1:
+            continue
+        if i <= new_days:
+            new[q] += 1
+        elif i <= old_days:
+            med[q] += 1
+        else:
+            old[q] += 1
+
+first_q = quarter(first)
+last_q = quarter(last)
+
+quarters = (q for q in chain(new, med, old) if first_q <= q <= last_q)
+quarters = tuple(sorted(set(quarters)))
+
+new_y = tuple(new[q] for q in quarters)
+med_y = tuple(med[q] for q in quarters)
+old_y = tuple(old[q] for q in quarters)
+sum_y = tuple(old[q] + med[q] for q in quarters)
+
+old_name = "older than {} days".format(old_days)
+med_name = "medium"
+new_name = "recent (less {} days old)".format(new_days)
+
+width = 0.9
+fig, ax = plt.subplots()
+ax.bar(quarters, old_y, width, label=old_name)
+ax.bar(quarters, med_y, width, label=med_name, bottom=old_y)
+ax.bar(quarters, new_y, width, label=new_name, bottom=sum_y)
+ax.legend(loc="upper left")
+ax.grid(True)
+ax.set_xlabel("quarter")
+ax.set_ylabel("Number or PRs pending")
+ax.tick_params(axis="x", labelrotation=90)
+fig.suptitle("State of the PR backlog at the end of each quarter")
+fig.set_size_inches(12.8, 7.2)  # default 100 dpi -> 720p
+fig.savefig("prs-backlog.png")
+
+print("Quarter,recent,medium,old,total")
+for q in quarters:
+    print("{},{},{},{},{}".format(q, new[q], med[q], old[q],
+            new[q] + med[q] + old[q]))