#!/bin/sh
# Pushes to one repository on a knot many times in parallel, as whoever goat
# is logged in as (see skills/push-with-goat). That account must be the
# repository's owner or a collaborator.
# Each push goes to its own branch (stress/<run>/<n>) so parallel pushes don't race
# on one ref, and carries a few freshly generated source files.
#
#   KNOT=enroute.anirudh.fi REPO=<repoDid> stress-push.sh [PUSHES] [PARALLEL] [FILES_PER_PUSH] [KB_PER_FILE]
set -eu

KNOT=${KNOT:-enroute.anirudh.fi}
REPO=${REPO:?set REPO to the repository's DID}
GOAT=${GOAT:-$HOME/go/bin/goat}
PUSHES=${1:-300}
PARALLEL=${2:-16}
FILES=${3:-4}
KB=${4:-256}
RUN=$(date +%H%M%S)
WORK=$(mktemp -d /tmp/stress-push.XXXXXX)
TOKEN_FILE=$WORK/token
LOG=$WORK/results

# a push token, reused until it is 3 minutes old: the knot accepts a
# receivePack token until it expires, and refuses any that lives over 300s
mint() {
	"$GOAT" account service-auth --aud "did:web:$KNOT" \
		--lxm org.tangled.git.receivePack --duration-sec 280 >"$TOKEN_FILE.new"
	mv "$TOKEN_FILE.new" "$TOKEN_FILE"
}
mint
minted=$(date +%s)

git init -q -b main "$WORK/base"
git -C "$WORK/base" -c user.name=bot -c user.email=bot@anirudh.fi \
	commit -q --allow-empty -m "stress base"

# source-looking text that doesn't compress away: random identifiers in Go-ish code
gen_file() { # path kb seed
	awk -v kb="$2" -v seed="$3" 'BEGIN {
		srand(seed); target = kb * 1024; n = 0
		print "package stress\n"
		while (n < target) {
			name = ""; for (i = 0; i < 12; i++) name = name sprintf("%c", 97 + int(rand() * 26))
			line = sprintf("func %s(x int) int { return x*%d + %d } // %08x\n", name, int(rand()*1e6), int(rand()*1e6), int(rand()*4294967295))
			printf "%s", line; n += length(line)
		}
	}' >"$1"
}

push_one() { # n
	n=$1
	dir=$WORK/w$n
	git clone -q --shared "$WORK/base" "$dir"
	mkdir -p "$dir/pkg$n"
	i=0
	while [ "$i" -lt "$FILES" ]; do
		gen_file "$dir/pkg$n/file$i.go" "$KB" "$n$i$$"
		i=$((i + 1))
	done
	git -C "$dir" add -A
	git -C "$dir" -c user.name=bot -c user.email=bot@anirudh.fi commit -q -m "stress push $n"
	start=$(date +%s.%N)
	if git -C "$dir" -c credential.helper= \
		-c "credential.helper=!f() { [ \"\$1\" = get ] || exit 0; echo username=x; echo password=\$(cat $TOKEN_FILE); }; f" \
		push -q "https://$KNOT/$REPO" "HEAD:refs/heads/stress/$RUN/$n" >"$dir.out" 2>&1; then
		status=ok
	else
		status=FAIL
	fi
	end=$(date +%s.%N)
	printf '%s %s %.2f\n' "$n" "$status" "$(awk -v a="$start" -v b="$end" 'BEGIN{print b-a}')" >>"$LOG"
	if [ "$status" != ok ] && [ "$(grep -c FAIL "$LOG")" -le 5 ]; then
		echo "push $n failed:"; sed "s/^/  /" "$dir.out"
	fi
	rm -rf "$dir"
}

echo "pushing $PUSHES times, $PARALLEL at once, $FILES x ${KB}KB files each, to $REPO"
export RUN WORK TOKEN_FILE LOG FILES KB KNOT REPO
started=$(date +%s)
n=1
while [ "$n" -le "$PUSHES" ]; do
	if [ $(( $(date +%s) - minted )) -ge 180 ]; then
		mint; minted=$(date +%s)
	fi
	# a batch of PARALLEL pushes, then wait for all of it
	batch=0
	while [ "$batch" -lt "$PARALLEL" ] && [ "$n" -le "$PUSHES" ]; do
		push_one "$n" &
		n=$((n + 1)); batch=$((batch + 1))
	done
	wait
	printf "%d/%d done\n" "$(wc -l <"$LOG")" "$PUSHES"
done
echo
ok=$(grep -c ' ok ' "$LOG" || true)
fail=$(grep -c ' FAIL ' "$LOG" || true)
elapsed=$(( $(date +%s) - started ))
echo "done in ${elapsed}s: $ok ok, $fail failed"
[ "$fail" -le 5 ] || echo "(showed the first 5 failures; every push's status is in $LOG)"
awk '$2=="ok"{print $3}' "$LOG" | sort -n | awk '{a[NR]=$1} END {if (NR) printf "push seconds: p50 %.2f  p90 %.2f  max %.2f\n", a[int(NR*0.5)+1], a[int(NR*0.9)+1], a[NR]}'
echo "remote branches: $(git ls-remote "https://$KNOT/$REPO" "refs/heads/stress/$RUN/*" | wc -l)"
echo "results: $LOG"
[ "$fail" -eq 0 ]