The Ultimate Guide to Envoy Websocket: Everything You Need to Know

Envoy is an open-source edge and service proxy designed for cloud-native applications. It is a powerful tool that helps with load balancing, service discovery, and routing. Envoy has become increasingly popular in recent years because of its ability to handle large-scale deployments in fast-paced environments.

One of the key features of Envoy is its support for WebSockets. In this article, we will explore what WebSockets are, why they are important, and how Envoy supports them.

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What are WebSockets?

WebSockets are a protocol that enables real-time communication between a client and a server. Unlike traditional HTTP requests, which are one-way and stateless, WebSockets create a persistent connection between the client and server. This allows data to be sent and received in real-time, without the need for repeated requests.

WebSockets were first introduced in 2008 as part of HTML5. Since then, they have become increasingly popular for applications that require real-time data transfer, such as chat apps, online gaming, and financial trading platforms.

Why are WebSockets important?

WebSockets are important because they enable real-time communication between a client and server. This has a wide range of applications, from chat apps to online gaming, and even financial trading platforms.

In the past, real-time communication was achieved using techniques such as long polling or server-sent events. However, these techniques were not ideal for applications that required real-time data transfer, as they could be slow, resource-intensive, and unreliable.

WebSockets, on the other hand, create a persistent connection between the client and server, allowing data to be sent and received in real-time. This makes them ideal for applications that require real-time data transfer.

How does Envoy support WebSockets?

Envoy supports WebSockets through its HTTP filter chain. When a WebSocket request is received, Envoy uses its HTTP filter chain to handle the request. The HTTP filter chain processes the WebSocket request in the same way it would process any other HTTP request.

Envoy also supports WebSocket routing, which allows WebSocket requests to be routed to specific services or endpoints. This is done using the same routing configuration as traditional HTTP requests.

WebSocket routing with Envoy

WebSocket routing with Envoy is similar to traditional HTTP routing. Requests are routed based on the URL path and host header. For example, if a WebSocket request is received with the following URL:

“`ws://example.com/chat“`

Envoy will route the request to the service or endpoint configured for the “/chat” path under the “example.com” host header.

WebSocket routing configuration

WebSocket routing configuration in Envoy is done using the “route” configuration. The route configuration specifies how requests should be routed based on the URL path and host header.

Here is an example of a route configuration for WebSocket requests:

“`{“name”: “websocket_route”,”match”: {“prefix”: “/chat”},”route”: {“cluster”: “chat_service”,”timeout”: “60s”,”websocket_upgrade”: true}}“`

This configuration specifies that WebSocket requests with a URL path prefix of “/chat” should be routed to the “chat_service” cluster. The “timeout” parameter specifies the maximum amount of time to wait for a response from the service. The “websocket_upgrade” parameter tells Envoy to upgrade the connection to a WebSocket connection.

WebSocket load balancing with Envoy

Envoy also supports WebSocket load balancing, which allows WebSocket requests to be distributed across multiple instances of a service. This is done using the same load balancing configuration as traditional HTTP requests.

WebSocket load balancing configuration

WebSocket load balancing configuration in Envoy is done using the “cluster” configuration. The cluster configuration specifies how requests should be load balanced across multiple instances of a service.

Here is an example of a cluster configuration for WebSocket requests:

“`{“name”: “chat_service”,”type”: “sds”,”connect_timeout”: “0.25s”,”lb_policy”: “round_robin”,”circuit_breakers”: {“thresholds”: [{“priority”: “HIGH”,”max_connections”: 1000}]},”transport_socket”: {“name”: “tls”,”typed_config”: {“@type”: “type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.UpstreamTlsContext”,”common_tls_context”: {“tls_certificates”: [{“certificate_chain”: {“filename”: “/etc/certs/server.crt”},”private_key”: {“filename”: “/etc/certs/server.key”}}],”validation_context”: {“trusted_ca”: {“filename”: “/etc/certs/root-ca.crt”}}}}},”hosts”: [{“url”: “tcp://192.0.2.1:8080”},{“url”: “tcp://192.0.2.2:8080”},{“url”: “tcp://192.0.2.3:8080”}]}“`

This configuration specifies a cluster called “chat_service” that uses round-robin load balancing to distribute requests across three instances of the service. The “circuit_breakers” parameter specifies that the cluster should break the circuit if it exceeds 1000 connections. The “transport_socket” parameter specifies that the connection should use TLS. The “hosts” parameter specifies the IP addresses and ports of the instances of the service.

WebSocket security with Envoy

Envoy supports WebSocket security through its transport layer security (TLS) configuration. TLS is used to encrypt and secure the connection between the client and server.

WebSocket TLS configuration

WebSocket TLS configuration in Envoy is done using the “transport_socket” configuration. The transport_socket configuration specifies how the connection should be secured using TLS.

Here is an example of a transport_socket configuration for WebSocket requests:

“`{“name”: “tls”,”typed_config”: {“@type”: “type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.DownstreamTlsContext”,”common_tls_context”: {“tls_certificates”: [{“certificate_chain”: {“filename”: “/etc/certs/server.crt”},”private_key”: {“filename”: “/etc/certs/server.key”}}],”validation_context”: {“trusted_ca”: {“filename”: “/etc/certs/root-ca.crt”}}}}}“`

This configuration specifies that the connection should use TLS with the server certificate “/etc/certs/server.crt” and private key “/etc/certs/server.key”. The “validation_context” parameter specifies the trusted root certificate authority.

WebSocket health checking with Envoy

Envoy supports WebSocket health checking, which allows Envoy to monitor the health of WebSocket connections and instances of a service.

WebSocket health checking configuration

WebSocket health checking configuration in Envoy is done using the “health_check” configuration. The health_check configuration specifies how Envoy should monitor the health of WebSocket connections and instances of a service.

Here is an example of a health_check configuration for WebSocket requests:

“`{“timeout”: “2s”,”interval”: “10s”,”unhealthy_threshold”: 3,”healthy_threshold”: 2,”grpc_health_check”: {“serviceName”: “chat_service”}}“`

This configuration specifies that Envoy should check the health of the WebSocket connection every 10 seconds, with a timeout of 2 seconds. The “unhealthy_threshold” parameter specifies the number of failed health checks required to mark the instance as unhealthy. The “healthy_threshold” parameter specifies the number of successful health checks required to mark the instance as healthy. The “grpc_health_check” parameter specifies the service name of the instance.

Conclusion

In conclusion, Envoy is a powerful tool that supports WebSockets, load balancing, security, and health checking. This makes it an ideal choice for deployments that require real-time communication and scalability.

If you are interested in using Envoy for your next project, be sure to check out the official documentation for more information.

FAQ

What is Envoy?

Envoy is an open-source edge and service proxy designed for cloud-native applications. It is a powerful tool that helps with load balancing, service discovery, and routing.

What are WebSockets?

Why are WebSockets important?

How does Envoy support WebSockets?

What is WebSocket routing with Envoy?

WebSocket routing with Envoy allows WebSocket requests to be routed to specific services or endpoints. This is done using the same routing configuration as traditional HTTP requests.

What is WebSocket load balancing with Envoy?

WebSocket load balancing with Envoy allows WebSocket requests to be distributed across multiple instances of a service. This is done using the same load balancing configuration as traditional HTTP requests.

What is WebSocket security with Envoy?

WebSocket security with Envoy is achieved through its transport layer security (TLS) configuration. TLS is used to encrypt and secure the connection between the client and server.

What is WebSocket health checking with Envoy?

WebSocket health checking with Envoy allows Envoy to monitor the health of WebSocket connections and instances of a service. This ensures that instances are healthy and able to handle requests.