/cLoki

cLoki: like Grafana Loki, but for Clickhouse

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cLoki

like Loki, but for ClickHouse

cLoki is a flexible Loki & Tempo compatible LogQL API built on top of ClickHouse
Natively supports Grafana and any LogQL clients for querying, processing, ingesting, tracing and alerting

💡 Get started using the cLoki Wiki
:octocat: Join us! All Contributions are Welcome!

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Project Background

The Loki API and its Grafana native integration are brilliant, simple and appealing - but we just love ClickHouse.

cLoki implements the same API functionality as Loki, buffered by a fast bulking LRU sitting on top of ClickHouse tables and relying on its columnar search and insert performance alongside solid distribution and clustering capabilities for stored data. Just like Loki, cLoki does not parse or index incoming logs, but rather groups log streams using the same label system as Prometheus.

🔥 LogQL: Supported Features

cLoki implements a broad range of LogQL Queries to provide transparent compatibility with the Loki API
The Grafana Loki datasource can be used to natively query logs and display extracted timeseries

🎉 No plugins needed

🔥 Follow our examples to get started


⛽ Log Streams

cLoki supports input via Push API using JSON or Protobuf and it is compatible with Promtail and any other Loki compatible agent

Our preferred companion for parsing and shipping log streams to cLoki is paStash with extensive interpolation capabilities to create tags and trim any log fat. Sending JSON formatted logs is suggested when dealing with metrics.


🔥 CliQL: Experimental 2.0 Features

cLoki implements custom query functions for ClickHouse timeseries extraction, allowing direct access to any existing table

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Timeseries

Convert columns to tagged timeseries using the emulated loki 2.0 query format

<aggr-op> by (<labels,>) (<function>(<metric>[range_in_seconds])) from <database>.<table> where <optional condition>
Examples
avg by (source_ip) (rate(mos[60])) from my_database.my_table
sum by (ruri_user, from_user) (rate(duration[300])) from my_database.my_table where duration > 10

ClickHouse

Convert columns to tagged timeseries using the experimental clickhouse function

Example

clickhouse({ 
  db="my_database", 
  table="my_table", 
  tag="source_ip", 
  metric="avg(mos)", 
  where="mos > 0", 
  interval="60" 
})
Query Options
parameter description
db clickhouse database name
table clickhouse table name
tag column(s) for tags, comma separated
metric function for metric values
where where condition (optional)
interval interval in seconds (optional)
timefield time/date field name (optional)

🔥 Tempo: Supported Features

cLoki Pulse offers experimental support for the Grafana Tempo API providing span ingestion and querying

At database level, Tempo Spans/Traces are stored as tagged Logs and are accessible from both LogQL and Tempo APIs


Setup

Check out the Wiki for detailed instructions or choose a quick method:

🚏 GIT (Manual)

Clone this repository, install with npmand run using nodejs 14.x (or higher)

npm install
CLICKHOUSE_SERVER="my.clickhouse.server" CLICKHOUSE_AUTH="default:password" CLICKHOUSE_DB="cloki" node cloki.js
🚏 NPM

Install cloki as global package on your system using npm

sudo npm install -g cloki
cd $(dirname $(readlink -f `which cloki`)) \
  && CLICKHOUSE_SERVER="my.clickhouse.server" CLICKHOUSE_AUTH="default:password" CLICKHOUSE_DB="cloki" cloki
🚏 PM2
sudo npm install -g cloki pm2
cd $(dirname $(readlink -f `which cloki`)) \
  && CLICKHOUSE_SERVER="my.clickhouse.server" CLICKHOUSE_AUTH="default:password" CLICKHOUSE_DB="cloki" pm2 start cloki
pm2 save
pm2 startup
🚏 Docker

For a fully working demo, check the docker-compose example


Logging

The project uses pino for logging and by default outputs JSON'ified log lines. If you want to see "pretty" log lines you can start cloki with npm run pretty

Configuration

The following ENV Variables can be used to control cLoki parameters and backend settings.

ENV Default Usage
CLICKHOUSE_SERVER localhost Clickhouse Server address
CLICKHOUSE_PORT 8123 Clickhouse Server port
CLICKHOUSE_DB cloki Clickhouse Database Name
CLICKHOUSE_AUTH default: Clickhouse Authentication (user:password)
CLICKHOUSE_PROTO http Clickhouse Protocol (http, https)
CLICKHOUSE_TIMEFIELD record_datetime Clickhouse DateTime column for native queries
BULK_MAXAGE 2000 Max Age for Bulk Inserts
BULK_MAXSIZE 5000 Max Size for Bulk Inserts
BULK_MAXCACHE 50000 Max Labels in Memory Cache
LABELS_DAYS 7 Max Days before Label rotation
SAMPLES_DAYS 7 Max Days before Timeseries rotation
HOST 0.0.0.0 cLOKi API IP
PORT 3100 cLOKi API PORT
CLOKI_LOGIN undefined Basic HTTP Username
CLOKI_PASSWORD undefined Basic HTTP Password
READONLY false Readonly Mode, no DB Init
FASTIFY_BODYLIMIT 5242880 API Maximum payload size in bytes
FASTIFY_REQUESTTIMEOUT 0 API Maximum Request Timeout in ms
FASTIFY_MAXREQUESTS 0 API Maximum Requests per socket
TEMPO_SPAN 24 Default span for Tempo queries in hours
TEMPO_TAGTRACE false Optional tagging of TraceID (expensive)
DEBUG false Debug Mode (for backwards compatibility)
LOG_LEVEL info Log Level
HASH short-hash Hash function using for fingerprints. Currently supported short-hash and xxhash64 (xxhash64 function)

Project Status

Consult the Wiki for a detailed list of supported features, changelog and API functionality


Acknowledgements

cLoki is not affiliated or endorsed by Grafana Labs. All rights belong to their respective owners.