Print Timeline

1"""Print a DFS-indented tree of spans, reconstructed from parent_span_id.
2
3Usage:
4  python3 scripts/print_timeline.py FILE
5
6Env vars:
7  MAX_LEN  — truncation limit for span names (default 120, 0 = unlimited)
8"""
9
10import os
11import sys
12
13from _common import SPAN_KIND, fmt_duration, is_root, load_trace_file, truncate
14
15
16max_len = int(os.environ.get("MAX_LEN", "120"))
17
18spans = load_trace_file(sys.argv[1])
19if not spans:
20    print("No spans in payload.", file=sys.stderr)
21    sys.exit(1)
22
23# Build span_id -> span and parent_span_id -> [children] indexes.
24# Sort children by timestamp so DFS prints chronologically within each branch.
25by_id = {}
26children = {}
27for span in spans:
28    sid = span.get("span_id")
29    if sid:
30        by_id[sid] = span
31    pid = span.get("parent_span_id") or ""
32    children.setdefault(pid, []).append(span)
33
34for kids in children.values():
35    kids.sort(key=lambda s: s.get("timestamp", ""))
36
37roots = [s for s in spans if is_root(s)]
38roots.sort(key=lambda s: s.get("timestamp", ""))
39
40trace_id = spans[0].get("trace_id", "?")
41print("=" * 80)
42print(f"TIMELINE — trace {trace_id}  ({len(spans)} spans, {len(roots)} root(s))")
43print("=" * 80)
44
45
46def render(span, depth):
47    indent = "  " * depth
48    name = truncate(span.get("name", "?"), max_len)
49    err = " [ERR]" if span.get("status_code") == 2 else ""
50    kind = SPAN_KIND.get(span.get("kind"), span.get("kind"))
51    print(f"{indent}- [{span.get('service_name', '?')}] {name}  ({fmt_duration(span.get('duration_nano'))}) <{kind}>{err}")
52    print(f"{indent}  span_id={span.get('span_id', '?')}")
53    sid = span.get("span_id")
54    for kid in children.get(sid, []):
55        render(kid, depth + 1)
56
57
58for root in roots:
59    render(root, 0)
60
61# Render orphan subtrees (their parent isn't in the payload, but the span itself is).
62orphan_roots = []
63for span in spans:
64    if is_root(span):
65        continue
66    pid = span.get("parent_span_id") or ""
67    if pid not in by_id:
68        orphan_roots.append(span)
69
70if orphan_roots:
71    print()
72    print(f"--- ORPHAN SUBTREES ({len(orphan_roots)} — parent_span_id not in payload) ---")
73    orphan_roots.sort(key=lambda s: s.get("timestamp", ""))
74    for span in orphan_roots:
75        render(span, 0)