Cloudflare: checks and maintenance

Do the Cloudflare setup first.

Scheduled checks on recent data

The check mode runs every 5 minutes. It asks two questions of the table and posts to a webhook when either has an answer:

• Which pumps averaged above 80° over the last 10 minutes? A SQL query over recent data. The time filter skips every file whose time range lies outside the window, before any data is read.
• Which pumps have sent nothing for 15 minutes? lake.latest() answers from the last-value index, without scanning the table.

cat >> timelake.env <<'EOF'
export ALERT_WEBHOOK="<incoming webhook url>"
EOF

*/5 * * * * cd $HOME/timelake && . ./timelake.env && $HOME/.local/bin/uv run --with timelake --with boto3 writer.py check >> check.log 2>&1

The body is {"text": "…"}, which a Slack incoming webhook takes as is; change it for other services. Change the SQL to check anything the table holds: a rate of change, a counter that stopped increasing, or readings outside a band per site (join a devices table). Over longer windows, a rollup keeps the query small.

Maintenance

Each append already merges small files and removes duplicates. An hourly timelake maintain also sorts each finished day into one file, applies retention, and deletes files no version needs:

0 * * * * cd $HOME/timelake && . ./timelake.env && $HOME/.cargo/bin/timelake maintain >> maintain.log 2>&1