gRPC

• GRPCServer
  • Example Requests
• GRPCProxy

GRPCServer

The GRPCServer in Easegress provides robust functionality tailored to gRPC protocol interactions. With its IP filtering feature, traffic can be selectively allowed or blocked, ensuring that only desired clients can communicate with the services. Additionally, the server’s routing rules offer flexible methods to determine how each incoming request is processed and forwarded, based on host, method, headers, and other criteria.

name: server-grpc
kind: GRPCServer
port: 8080

---
title: The maximum number of connections allowed by gRPC Server.
linkTitle: The maximum number of connections allowed by gRPC Server.
weight: 7
---
---
title: Default value 10240
linkTitle: Default value 10240
weight: 7
---
maxConnections: 10240

---
title: IP Filter for all traffic under the server
linkTitle: IP Filter for all traffic under the server
weight: 7
---
ipFilter:
  blockIPs: []
  allowIPs: []
  blockByDefault: false

---
title: routing rules
linkTitle: routing rules
weight: 7
---
rules:
---
title: Rules for host matching.
linkTitle: Rules for host matching.
weight: 7
---
---
title: If not match, GRPCServer will check next rule.
linkTitle: If not match, GRPCServer will check next rule.
weight: 7
---
- host: <your-host>
  hostRegexp: <your-host-regexp>

  methods: 
  - method: /Sale/AddProduct # Exact method match
    backend: sale-pipeline

  - methodPrefix: /IT        # Matches method with the given prefix
    backend: it-pipeline

  - headers:                 # Matches by header
    - key: x-geo-country
      values: ["CN", "EU", "US"]
    - key: user-agent
      values: ["SaleClient/1.0.0"]
    matchAllHeader: false
    backend: header-pipeline

  - methodRegexp: .*         # Match by regexp
    backend: other-pipeline

---
title: more rules
linkTitle: more rules
weight: 7
---
- methods:
  ...

For an in-depth exploration of the GRPCServer settings, please refer to the GRPCServer.

Example Requests

• A gRPC request with method /Sale/AddProduct will be routed to the sale-pipeline.
• Any request with a method starting with /IT (e.g., /IT/UpdateSoftware) will be directed to the it-pipeline.
• If a client sends a request with headers x-geo-country set to CN and user-agent set to SaleClient/1.0.0, it will be handled by the header-pipeline.
• All other requests (due to the wildcard methodRegexp) will be sent to the other-pipeline.

GRPCProxy

The GRPCProxy filter in Easegress serves as a specialized proxy designed for gRPC backend services. This filter facilitates both unary and streaming RPCs, ensuring seamless communication in a gRPC ecosystem.

Here’s a basic configuration of the GRPCProxy filter that directs incoming gRPC connections to two backend servers, 192.168.1.1:80 and 192.168.1.2:80:

name: demo-pipeline
kind: Pipeline
flow: 
- proxy

filters:
- kind: GRPCProxy
  name: proxy
  pools:
   - loadBalance:
       policy: roundRobin
     servers:
      - url: http://192.168.1.1:80
      - url: http://192.168.1.2:80

Same as the Proxy filter:

• a filter can be configured on a pool.
• the servers of a pool can be configured dynamically via service discovery.
• when there are multiple servers in a pool, the pool can do a load balance between them.

Because gRPC does not support the http Connect method, it does not support tunneling mode, we provide a new load balancer policy.forward to achieve a similar effect.

Note that each gRPC client establishes a connection with Easegress. However, Easegress may utilize a single connection when forwarding requests from various clients to a gRPC server, due to its use of HTTP2. This action could potentially disrupt some client or server applications. For instance, if the client applications are structured to directly connect to the server, and both the client and server have the ability to request a connection closure, then problems may arise once Easegress is installed between them. If the server wants to close the connection of one client, it closes the shared connection with Easegress, thus affecting other clients.

For more details about GRPCProxy filter.