This script is intended to run periodically via a systemd timer (e.g., once per week) to generate updated Bitcoin UTXO hints.

generate_hints.sh

#!/usr/bin/env bash
set -euo pipefail
umask 022

BITCOINCLI="$HOME/dev/bitcoin/build/bin/bitcoin-cli"
HINT_DIR="$HOME/hints"
NEW_HINT_DIR="$HOME/hints_new"

echo "=== $(date) starting generatetxohints ==="

# 1) Check RPC and extract blockchain info
BLOCKCHAININFO_OUTPUT=$("$BITCOINCLI" getblockchaininfo 2>&1) || {
  echo "ERROR: bitcoind not reachable via RPC" >&2
  exit 1
}

CHAIN_NAME=$(echo "$BLOCKCHAININFO_OUTPUT"      | grep '"chain"'         | sed 's/.*"chain": *"\([^"]*\)".*/\1/')
BLOCK_HEIGHT=$(echo "$BLOCKCHAININFO_OUTPUT"    | grep '"blocks"'        | sed 's/.*"blocks": *\([0-9]*\).*/\1/')
BEST_BLOCK_HASH=$(echo "$BLOCKCHAININFO_OUTPUT" | grep '"bestblockhash"' | sed 's/.*"bestblockhash": *"\([^"]*\)".*/\1/')
HASH_SUFFIX="${BEST_BLOCK_HASH: -8}"

FINAL_HINT="$NEW_HINT_DIR/${CHAIN_NAME}_${BLOCK_HEIGHT}_${HASH_SUFFIX}.hints"
VERSIONED_HINT_GZ="$HINT_DIR/${CHAIN_NAME}_${BLOCK_HEIGHT}_${HASH_SUFFIX}.hints.gz"
LATEST_HINT_GZ="$HINT_DIR/${CHAIN_NAME}.hints.gz"

echo "Chain: $CHAIN_NAME | Block: $BLOCK_HEIGHT | Hash suffix: $HASH_SUFFIX"

# 2) Ensure new hints directory exists
rm -rf "$NEW_HINT_DIR"
mkdir -p "$NEW_HINT_DIR"
chmod 755 "$NEW_HINT_DIR"
echo "Cleaned up $NEW_HINT_DIR"

# 3) Generate hints in hints_new directory
if "$BITCOINCLI" --rpcclienttimeout=0 generatetxohints "$FINAL_HINT"; then
  echo "Generation finished successfully"

  # 4) Ensure hints directory exists
  mkdir -p "$HINT_DIR"
  chmod 755 "$HINT_DIR"

  # 5) Create versioned copy
  gzip -c "$FINAL_HINT" > "$VERSIONED_HINT_GZ"
  chmod 644 "$VERSIONED_HINT_GZ"
  echo "Created versioned hints: $VERSIONED_HINT_GZ"

  # 6) Replace latest copy
  rm -f "$LATEST_HINT_GZ"
  cp "$VERSIONED_HINT_GZ" "$LATEST_HINT_GZ"
  chmod 644 "$LATEST_HINT_GZ"
  echo "Updated latest hints: $LATEST_HINT_GZ"
else
  echo "ERROR: Hints generation failed" >&2
  exit 1
fi

echo "=== $(date) finished ==="

To create the services:
bitcoin-hints.service:

[Unit]
Description=Generate Bitcoin Hintsfile
After=bitcoind.service

[Service]
Type=oneshot
User=bitcoin
ExecStart=/home/bitcoin/scripts/generate_hints.sh
TimeoutStartSec=800min

StandardOutput=journal
StandardError=journal

bitcoin-hints.timer:

[Unit]
Description=Bitcoin Hintsfile Generator Timer
[Timer]
OnCalendar=Sat 20:00
Persistent=true
[Install]
WantedBy=timers.target

For the web server, you can use miniserve, rob hints-server or directly run it in nginx.

Just sanity-checking my assumptions: I need to run an unpruned fork of bitcoin core (link plz?) to get those, right?

Just sanity-checking my assumptions: I need to run an unpruned fork of bitcoin core (link plz?) to get those, right?

Yes. Currently you need a fullnode to generate the hintsfile.
You need to build the core from here. (updated to most recent hintsfile generation)

This is my most recent fork for hintsfile generation. Is this what you meant to link?

This is my most recent fork for hintsfile generation. Is this what you meant to link?

@rustaceanrob Currently I'm generating the hintsfile from the SwiftSync PR. I assumed Floresta was still using that hintsfile format for experiments, so I linked that one.

Do you think I should generate the hintsfile using the newer version you linked instead?

Oh I see, certainly do what is best for Floresta, I was just making sure you had the most up to date branch!