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131 lines
4.1 KiB
Markdown
131 lines
4.1 KiB
Markdown
## Configuration File Format
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While the NATS server has many flags that allow for simple testing of features, the NATS server products provide a flexible configuration format that combines the best of traditional formats and newer styles such as JSON and YAML.
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The NATS configuration file supports the following syntax:
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- Lines can be commented with `#` and `//`
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- Values can be assigned to properties with:
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- Equals sign: `foo = 2`
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- Colon: `foo: 2`
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- Whitespace: `foo 2`
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- Arrays are enclosed in brackets: `["a", "b", "c"]`
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- Maps are enclosed in braces: `{foo: 2}`
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- Maps can be assigned with no key separator
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- Semicolons can be used as terminators
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### Strings and Numbers
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The configuration parser is very forgiving, as you have seen:
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- values can be a primitive, or a list, or a map
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- strings and numbers typically do the right thing
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String values that start with a digit _can_ create issues. To force such values as strings, quote them.
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*BAD Config*:
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```
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listen: 127.0.0.1:4222
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authorization: {
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# BAD!
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token: 3secret
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}
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```
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Fixed Config:
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```
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listen: 127.0.0.1:4222
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authorization: {
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token: "3secret"
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}
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```
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### Variables
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Server configurations can specify variables. Variables allow you to reference a value from one or more sections in the configuration.
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Variables:
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- Are block-scoped
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- Are referenced with a `$` prefix.
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- Can be resolved from environment variables having the same name
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> If the environment variable value begins with a number you may have trouble resolving it depending on the server version you are running.
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```
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# Define a variable in the config
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TOKEN: "secret"
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# Reference the variable
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authorization {
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token: $TOKEN
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}
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```
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A similar configuration, but this time, the value is in the environment:
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```
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# TOKEN is defined in the environment
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authorization {
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token: $TOKEN
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}
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```
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export TOKEN="hello"; nats-server -c /config/file
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### Include Directive
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The `include` directive allows you to split a server configuration into several files. This is useful for separating configuration into chunks that you can easily reuse between different servers.
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Includes *must* use relative paths, and are relative to the main configuration (the one specified via the `-c` option):
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server.conf:
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```
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listen: 127.0.0.1:4222
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include ./auth.conf
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```
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> Note that `include` is not followed by `=` or `:`, as it is a _directive_.
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auth.conf:
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```
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authorization: {
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token: "f0oBar"
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}
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```
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```
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> nats-server -c server.conf
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```
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### Configuration Properties
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| Property | Description |
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| :------ | :---- |
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| [`authorization`](auth_intro.md) | configuration map for client authentication/authorization |
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| [`cluster`](cluster_config.md) | configuration map for clustering configuration |
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| `debug` | if `true` enable debug log messages |
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| [`gateway`](/gateways/gateway.md) | Gateway configuration map |
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| `host` | host for client connections |
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| [`http_port`](monitoring.md) | http port for server monitoring |
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| [`https_port`](monitoring.md) | https port for server monitoring |
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| [`leafnode`](/leafnodes/leafnode_conf.md) | Leafnode configuration map |
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| `listen` | host/port for client connections |
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| `max_connections` | Maximum number of active client connections |
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| `max_control_line` | Maximum length of a protocol line (including subject length) |
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| `max_payload` | Maximum number of bytes in a message payload |
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| `max_subscriptions` | Maximum numbers of subscriptions for a client connection |
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| [`operator`](/nats_tools/nsc/nsc.md#nats-server-configuration) | path to an operator JWT |
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| `port` | port for client connections |
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| [`resolver`](/nats_tools/nsc/nsc.md#nats-server-configuration) | Resolver type `MEMORY` or `URL` for account JWTs |
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| [`tls`](tls.md#tls-configuration) | configuration map for tls for client and http monitoring |
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| `trace` | if `true` enable protocol trace log messages |
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| `write_deadline` | Maximum number of seconds the server will block when writing a to a client (slow consumer) |
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### Configuration Reloading
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A server can reload most configuration changes without requiring a server restart or clients to disconnect by sending the nats-server a [signal](/nats_admin/signals.md):
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```
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> nats-server --signal reload
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``` |