Clickhouse HTTP proxy

[Роман Хавроненко]

Hi!

We have created an HTTP proxy for ClickHouse. It provides the following features:

• May proxy requests to multiple distinct ClickHouse clusters depending on the input user. For instance, requests from appserver user may go to stats-raw cluster, while requests from reportserver user may go to stats-aggregatecluster.
• May map input users to per-cluster users. This prevents from exposing real usernames and passwords used in ClickHouse clusters. Additionally this allows mapping multiple distinct input users to a single ClickHouse user.
• May accept incoming requests via HTTP and HTTPS.
• May limit HTTP and HTTPS access by IP/IP-mask lists.
• May limit per-user access by IP/IP-mask lists.
• May limit per-user query duration. Timed out queries are forcibly killed via KILL QUERY.
• May limit per-user requests rate.
• May limit per-user number of concurrent requests.
• All the limits may be independently set for each input user and for each per-cluster user.
• Evenly spreads requests among cluster nodes using least loaded + round robin technique.
• Monitors node health and prevents from sending requests to unhealthy nodes.
• Supports automatic HTTPS certificate issuing and renewal via Let’s Encrypt.
• May proxy requests to each configured cluster via either HTTP or HTTPS.

Check it at https://github.com/Vertamedia/chproxy 

If you have any idea for an improvement or found a bug do not hesitate to open an issue or submit a pull request.