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Configure TLS

TLS/SSL layer is very important not only for securing your connections but also to increase a chance to establish Websocket connection.

tip

In most situations you better put TLS termination task on your reverse proxy/load balancing software such as Nginx. This can be a good thing for performance.

There are situations though when you want to serve secure connections by Centrifugo itself.

There are two ways to do this: using TLS certificate cert and key files that you've got from your CA provider or using automatic certificate handling via ACME provider (only Let's Encrypt at this moment).

Using crt and key files​

In first way you already have cert and key files. For development you can create self-signed certificate - see this instruction as example.

config.json
{
  ...
  "tls": true,
  "tls_key": "server.key",
  "tls_cert": "server.crt"
}

And run:

./centrifugo --config=config.json

Automatic certificates​

For automatic certificates from Let's Encrypt add into configuration file:

config.json
{
  ...
  "tls_autocert": true,
  "tls_autocert_host_whitelist": "www.example.com",
  "tls_autocert_cache_dir": "/tmp/certs",
  "tls_autocert_email": "[email protected]",
  "tls_autocert_http": true,
  "tls_autocert_http_addr": ":80"
}

tls_autocert (boolean) says Centrifugo that you want automatic certificate handling using ACME provider.

tls_autocert_host_whitelist (string) is a string with your app domain address. This can be comma-separated list. It's optional but recommended for extra security.

tls_autocert_cache_dir (string) is a path to a folder to cache issued certificate files. This is optional but will increase performance.

tls_autocert_email (string) is optional - it's an email address ACME provider will send notifications about problems with your certificates.

tls_autocert_http (boolean) is an option to handle http_01 ACME challenge on non-TLS port.

tls_autocert_http_addr (string) can be used to set address for handling http_01 ACME challenge (default is :80)

When configured correctly and your domain is valid (localhost will not work) - certificates will be retrieved on first request to Centrifugo.

Also Let's Encrypt certificates will be automatically renewed.

There are two options that allow Centrifugo to support TLS client connections from older browsers such as Chrome 49 on Windows XP and IE8 on XP:

  • tls_autocert_force_rsa - this is a boolean option, by default false. When enabled it forces autocert manager generate certificates with 2048-bit RSA keys.
  • tls_autocert_server_name - string option, allows to set server name for client handshake hello. This can be useful to deal with old browsers without SNI support - see comment

grpc_api_tls_disable boolean flag allows to disable TLS for GRPC API server but keep it on for HTTP endpoints.

uni_grpc_tls_disable boolean flag allows to disable TLS for GRPC uni stream server but keep it on for HTTP endpoints.

TLS for GRPC API​

You can provide custom certificate files to configure TLS for GRPC API server.

  • grpc_api_tls boolean flag enables TLS for GRPC API server, requires an X509 certificate and a key file
  • grpc_api_tls_cert string provides a path to an X509 certificate file for GRPC API server
  • grpc_api_tls_key string provides a path to an X509 certificate key for GRPC API server

TLS for GRPC unidirectional stream​

Starting from Centrifugo v3.0.0 you can provide custom certificate files to configure TLS for GRPC unidirectional stream endpoint.

  • uni_grpc_tls boolean flag enables TLS for GRPC server, requires an X509 certificate and a key file
  • uni_grpc_tls_cert string provides a path to an X509 certificate file for GRPC uni stream server
  • uni_grpc_tls_key string provides a path to an X509 certificate key for GRPC uni stream server