pw

#!/usr/bin/env bash
# pw — pact/bd wrapper. Run 6 instrumentation.
#
# Run 5 learned that `bd close` fails silently under fleet load, and that
# `pact msg send --body-file -` can hang, only because two agents happened to
# mention it in prose. This makes the harness a measured subject instead: every
# invocation appends one JSON line with the command, wall-time, exit code and
# a stderr excerpt.
#
# Both of run 5's stories were then overturned by this log: the multi-path
# acquire "cap" was zsh not word-splitting an unquoted variable, and 46 of the
# 66 non-zero exits were 141 — SIGPIPE from the agent's own `| head`.
#
# Usage:  pw pact lease acquire foo --note "..."
#         pw bd close treadle-x --reason "..."
#
# It wraps foreign tools, which is most of its value: in run 6 every call over
# a second came from bd. That is also why it is not a pact subcommand — pact
# shelling out to bd to time bd would put back the dependency 0.9.0 removed.
#
# The log is append-only and one line per call, mirroring pact's own logs.
# It is per-agent, so 50 agents do not contend on it.
set -uo pipefail

AGENT="${PACT_AGENT:-unknown}"

# $PACT_HARNESS_DIR, else <repo root>/.harness. The root is the one pact itself
# resolves: `--git-common-dir` names the MAIN checkout's .git even from a linked
# worktree, so a 20-agent fleet spread over 20 worktrees writes one directory
# instead of 20 — the same reason `pact whoami` reports a pact dir outside the
# worktree you ran it from. Relative from the main checkout ("../.git"), absolute
# from a worktree; dirname+cd+pwd normalises both. No repo at all: fall back to
# the working directory rather than refusing to run.
if [ -n "${PACT_HARNESS_DIR:-}" ]; then
	LOGDIR="$PACT_HARNESS_DIR"
elif common=$(git rev-parse --git-common-dir 2>/dev/null) &&
	root=$(cd "$(dirname "$common")" && pwd); then
	LOGDIR="$root/.harness"
else
	LOGDIR="$PWD/.harness"
fi
mkdir -p "$LOGDIR"
LOG="$LOGDIR/$AGENT.jsonl"

start=$(date +%s.%N)
err=$(mktemp)
# stderr is teed through a PIPE, not a process substitution: the shell waits for
# a pipeline to finish, so "$err" is complete by the time it is read. With `2>
# >(tee …)` the wrapper raced its own tee and could log an empty excerpt for a
# command that had just printed the reason it failed. fd 3 carries stdout past
# the tee untouched, so `pw … | head` still sees exactly what the tool wrote.
{ "$@" 2>&1 1>&3 | tee "$err" >&2; rc=${PIPESTATUS[0]}; } 3>&1
end=$(date +%s.%N)

dur=$(awk -v a="$start" -v b="$end" 'BEGIN{printf "%.3f", b-a}')
# First 200 chars of stderr, flattened to one line. Newline, CR and TAB all
# have to go: a raw U+0009 inside a JSON string is as invalid as a raw newline,
# and the first pass at this fixed argv while leaving stderr on the old filter
# (bead .47). Same treatment for both fields, so they cannot drift again.
tail_err=$(head -c 200 "$err" | tr '\n\r\t' '   ' | sed 's/\\/\\\\/g; s/"/\\"/g')
rm -f "$err"

# 141 = 128+SIGPIPE: the command was killed because the CALLER stopped reading
# (`... | head`), not because it failed. Recording that as a failure would have
# the harness report claim bd/pact fell over when they did not — it showed up
# three times in the first wave. Flag it so the analysis can exclude it, and
# keep the raw code so nothing is hidden.
sigpipe=false
[ "$rc" = 141 ] && sigpipe=true

# argv must be flattened to ONE line: a --reason or --note containing newlines
# (they routinely do) would otherwise split one record across many lines and the
# log would no longer be one-JSON-object-per-line. This is the same torn-line
# failure the previous run went looking for in pact's own store; the wrapper had
# it, and 11 of the first 141 records were unparseable before this was fixed.
# Truncated to 400 chars because a full close reason is prose, not telemetry.
cmd=$(printf '%s ' "$@" | tr '\n\r\t' '   ' | head -c 400 | sed 's/\\/\\\\/g; s/"/\\"/g; s/ *$//')
printf '{"at":"%s","agent":"%s","tool":"%s","argv":"%s","secs":%s,"exit":%s,"sigpipe":%s,"stderr":"%s"}\n' \
	"$(date -u +%Y-%m-%dT%H:%M:%SZ)" "$AGENT" "$1" "$cmd" "$dur" "$rc" "$sigpipe" "$tail_err" >>"$LOG"

exit "$rc"