Configuration

The server reads its settings in this order. A later source overrides an earlier one:

The defaults in the code.
A YAML file. Give its path in TT_CONFIG_FILE or with the --config option.
Environment variables that start with TT_.

Names of the variables

A variable name has the prefix TT_, then the section, two underscores, and the key. For example, the YAML key http.addr is the variable TT_HTTP__ADDR.

The same settings in a YAML file:

http:
  addr: ":8080"
  cors_allow_origins:
    - "https://towertail.example.com"
log:
  level: info

HTTP

Variable	YAML key	Default	Description
`TT_HTTP__ADDR`	`http.addr`	`:8080`	The listen address.
`TT_HTTP__READ_TIMEOUT`	`http.read_timeout`	`30s`	The read timeout for a request.
`TT_HTTP__WRITE_TIMEOUT`	`http.write_timeout`	`30s`	The write timeout for a response.
`TT_HTTP__SHUTDOWN_TIMEOUT`	`http.shutdown_timeout`	`10s`	The maximum time for a clean stop.
`TT_HTTP__CORS_ALLOW_ORIGINS`	`http.cors_allow_origins`	`*`	The allowed CORS origins. A variable sets one origin. For a list, use the YAML file.
`TT_HTTP__RATE_LIMIT_RPS`	`http.rate_limit_rps`	`100`	Requests per second for each IP address, for all routes except `/v1/ingest`.
`TT_HTTP__INGEST_RATE_LIMIT_RPS`	`http.ingest_rate_limit_rps`	`1000`	Requests per second for each IP address, for the sampler routes `/v1/ingest` and `/v1/control`.

ClickHouse

Variable	YAML key	Default	Description
`TT_CLICKHOUSE__ADDR`	`clickhouse.addr`	`clickhouse:9000`	The ClickHouse address.
`TT_CLICKHOUSE__DATABASE`	`clickhouse.database`	`towertail`	The database name.
`TT_CLICKHOUSE__USER`	`clickhouse.user`	`towertail`	The user name.
`TT_CLICKHOUSE__PASSWORD`	`clickhouse.password`	(empty)	The password.
`TT_CLICKHOUSE__PASSWORD_FILE`	`clickhouse.password_file`	(empty)	A file that contains the password. The server reads it when the password is empty.
`TT_CLICKHOUSE__DIAL_TIMEOUT`	`clickhouse.dial_timeout`	`5s`	The connection timeout.
`TT_CLICKHOUSE__MAX_OPEN_CONNS`	`clickhouse.max_open_conns`	`16`	The maximum number of open connections.
`TT_CLICKHOUSE__MAX_IDLE_CONNS`	`clickhouse.max_idle_conns`	`4`	The maximum number of idle connections.
`TT_CLICKHOUSE__CONN_MAX_LIFETIME`	`clickhouse.conn_max_lifetime`	`10m`	The maximum life of a connection.
`TT_CLICKHOUSE__BATCH_FLUSH_ROWS`	`clickhouse.batch_flush_rows`	`5000`	The server writes a batch when it has this number of rows.
`TT_CLICKHOUSE__BATCH_FLUSH_BYTES`	`clickhouse.batch_flush_bytes`	`1048576`	The server writes a batch when it has this number of bytes.
`TT_CLICKHOUSE__BATCH_FLUSH_PERIOD`	`clickhouse.batch_flush_period`	`1s`	The server writes a batch at least at this interval.
`TT_CLICKHOUSE__DISABLED`	`clickhouse.disabled`	`false`	For tests only. When `true`, the server does not keep metrics and has no history.

Other settings

Variable	YAML key	Default	Description
`TT_STORAGE__PATH`	`storage.path`	`/var/lib/towertail`	The folder for `config.db`, which keeps nodes, tokens and settings.
`TT_INGEST__MAX_BODY_BYTES`	`ingest.max_body_bytes`	`16777216` (16 MiB)	The maximum size of one ingest request.
`TT_AUTH__BOOTSTRAP_TOKEN`	`auth.bootstrap_token`	(empty)	An admin token that the server adds at the start. Read Tokens.
`TT_LOG__LEVEL`	`log.level`	`info`	`debug`, `info`, `warn` or `error`.
`TT_LOG__FORMAT`	`log.format`	`json`	`json` or `text`.
`TT_CLOUD__MANAGED`	`cloud.managed`	`false`	Keep `false` for a self-hosted server.