xDS Explorer

xDS Explorer provides a RESTful interface for viewing the current state of resources that are discovered by an Envoy management server and exposed via its Aggregated Discovery Service (ADS).

Since ADS is only available via gRPC, it is unavailable client-side via web browsers for two reasons:

1. A gRPC connection must be established with the Envoy management server with a DiscoveryRequest.
2. The DiscoveryResponse returned in a gRPC connection stream is a protobuf message that must be marshaled into JSON.

So this service simply establishes the gRPC connection, creates the DiscoveryRequest with the given inputs, and returns the DiscoveryResponse as JSON.

Resource Types

ADS exposes Envoy resource types, all of which are available via xDS Explorer:

• Clusters (CDS)
• Cluster Load Assignments, e.g. Endpoints (EDS)
• Routes (RDS)
• Listeners (LDS)
• Secrets (SDS)

Basic Usage

• docker pull bcmendoza/xds-explorer to get the Docker image or make build to create bcmendoza/xds-explorer:latest.
• Add the image to your docker-compose setup with the Envoy management server. Expose port 3001 to your local machine. Set environment variables XDS_HOST and XDS_PORT.

  xds-explorer:
    image: bcmendoza/xds-explorer:latest
    environment:
      - XDS_HOST=gm-control
      - XDS_PORT=50000
    ports:
      - "3001:3001"

• Visit localhost:3001 in your browser.
• Select a ResourceType and fill out fields for Node, Zone, Clusters, and optionally ResourceNames (a comma-separated list). For example:

ResourceType: "ClusterLoadAssignment"

Node: "default-node"

Zone: "default-zone"

Cluster: "catalog"

ResourceNames: ""

API

Route: /request

Method: POST

Initializes or updates the current DiscoveryRequest being made to the Envoy management server.

Sample Request Body:

{
  "resourceType": "ClusterLoadAssignment",
  "node": "default-node",
  "zone": "default-zone",
  "cluster": "catalog",
  "resourceNames": ["catalog"]
}

Response:

{"request updated": true}

---

Route: /listen

Method: GET

Retrieves the current DiscoveryResponse being made to the Envoy management server (or an empty array if no request has been made).

Response:

[
  {
    "cluster_name": "catalog",
    "endpoints": [
      {
        "lb_endpoints": [
          {
            "HostIdentifier": {
              "Endpoint": {
                "address": {
                  "Address": {
                    "SocketAddress": {
                      "address": "192.168.16.8",
                      "PortSpecifier": {
                        "PortValue": 8080
                      }
                    }
                  }
                }
              }
            },
            "health_status": 1,
            "metadata": {}
          }
        ]
      }
    ]
  }
]