ClickHouse Input

Reads rows from ClickHouse tables via the HTTP API and converts them to JSON.

How it works

1. Connects to ClickHouse using the HTTP interface.
2. Queries specified tables or executes a custom SQL query with FORMAT JSONEachRow.
3. Each row is emitted as a JSON record.
4. Namespace convention: clickhouse.{database}.{table_name}.

Configuration

data_sources:
  source:
    Clickhouse:
      url: "http://localhost:8123"
      database: default
      user: default
      password: secret
      tables: ["events", "metrics"]

Configuration variables

Variable	Default	Description
url	http://localhost:8123	ClickHouse HTTP endpoint
database	default	Database name
user	default	Username
password		Password
tables		List of tables to read
query		Custom SQL query (overrides tables)
batch_size_rows	10000	Rows per ingest batch
format	json	Data format

Authentication

Use the configured ClickHouse user and password, or rely on the default local user for development. For security best practices, we strongly advise against storing the password in skippr.yml. Use environment variable interpolation instead: replace the password value with your own ${ENV_VAR} reference.

The relevant part of skippr.yml looks like this:

data_sources:
  source:
    Clickhouse:
      password: "${CLICKHOUSE_PASSWORD}"

Set the env var before running skipprd:

macOS / Linux

export CLICKHOUSE_PASSWORD="secret"

Windows PowerShell

$env:CLICKHOUSE_PASSWORD = "secret"

Windows Command Prompt

set CLICKHOUSE_PASSWORD=secret

Troubleshooting

Symptom	Fix
authentication failed	Verify the ClickHouse user, password, and database name.
connection refused	Check the HTTP URL, port, and network access to the ClickHouse endpoint.