Error: Invalid label name when using non-ASCII characters in tags

[candies404]

📑 I have found these related issues/pull requests

No correlation has been found

🛡️ Security Policy

• I agree to have read this project Security Policy

Description

When using non-ASCII characters (such as Chinese) in tag names, the system throws an "Invalid label name" error during Prometheus metrics initialization.

👟 Reproduction steps

1. Create a tag with a non-ASCII name (e.g., Chinese characters) in Uptime Kuma
2. Restart the Uptime Kuma service or trigger Prometheus metrics initialization

👀 Expected behavior

The system should handle non-ASCII tag names gracefully, either by converting them to valid Prometheus label names or by using a separate field for Prometheus-compatible names.

😓 Actual Behavior

The system crashes with an "Invalid label name" error when initializing Prometheus metrics.

🐻 Uptime-Kuma Version

2.0.0-dev

💻 Operating System and Arch

Ubuntu Linux

🌐 Browser

127.0.6533.120

🖥️ Deployment Environment

• Runtime: Docker
• Database: external mariadb
• Filesystem used to store the database on: btrfs
• number of monitors: 5

📝 Relevant log output

Error message:
Trace: Error: Invalid label name
    at new Metric (/app/node_modules/prom-client/lib/metric.js:39:10)
    at new Gauge (/app/node_modules/prom-client/lib/gauge.js:19:1)
    at Prometheus.initMetrics (/app/server/prometheus.js:61:45)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Prometheus.createAndInitMetrics (/app/server/prometheus.js:96:9)
    at async Proxy.start (/app/server/model/monitor.js:349:27)
    at async startMonitors (/app/server/server.js:1805:9)
    at process.unexpectedErrorHandler (/app/server/server.js:1859:13)
    at process.emit (node:events:519:28)
    at emitUnhandledRejection (node:internal/process/promises:250:13)
    at throwUnhandledRejectionsMode (node:internal/process/promises:385:19)
    at processPromiseRejections (node:internal/process/promises:470:17)
    at process.processTicksAndRejections (node:internal/process/task_queues:96:32)

[louislam]

Thanks for finding the root cause. I was experiencing this issue last week too. It should be related to this pull request:

#4704 (comment)