Postman.md

Table of Contents

• Postman and gRPC
• Requirement
• Clone the gnmi repo on your automation setup
• Install Postman Desktop Agent on your automation setup
• Create a new workspace or select an existing one
• Create and activate a new environment
• Create a new request (Capablities)
• Verify the new API
• Add another request (Subscribe) to the new collection (gNMI)

Postman and gRPC

We can use Postman to interact with CVP using gRPC (gNMI, resource APIs).
The gRPC port is 443 and gPRC uses HTTP2.

Requirement

Token based authentication is required. To enable token based authentication, refer to this directory

Clone the gnmi repo on your automation setup

The gNMI proto file is https://github.com/openconfig/gnmi/blob/master/proto/gnmi/gnmi.proto

cd $HOME  
mkdir -p github.com/openconfig
git clone https://github.com/openconfig/gnmi.git github.com/openconfig/gnmi  
ls github.com/openconfig/gnmi

Install Postman Desktop Agent on your automation setup

Importing a proto file and invoking gRPC services is a new Postman feature.
To connect with a gRPC server (CVP) requires using Postman Desktop Agent (this is not supported with Postman web).
In this example we are using Postman Desktop Agent Version 9.26.8.

Create a new workspace or select an existing one

Create and activate a new environment

From your workspace, you will need to create and activate a new environment

Click on Environment and create a new environment.
Provide a name to the new environment. Define these two variables:

• grpcServerUrl: use the CloudVision IP address
• token: use the token generated previously

Activate the environment.

Create a new request (Capablities)

From your workspace, select New > gRPC Request

Use the variable grpcServerUrl for the server URL
Select the authorization type Bearer token and use the variable token for the token

Click on Import a .proto file in service definition

Select the .proto file from the repo you cloned, and define the import path to use if your .proto file import other .proto files.
The gNMI proto file is https://github.com/openconfig/gnmi/blob/master/proto/gnmi/gnmi.proto
It imports https://github.com/openconfig/gnmi/blob/master/proto/gnmi_ext/gnmi_ext.proto

Click on Next and import your .proto file as an API to reuse it in other requests with Postman

Select the RPC Capabilities from the gNMI service

Enable TLS

Click on Invoke.
You should get a response.

Save the new request (name it Capabilities) to a new collection (name it gNMI)

Verify the new API

From your workspace, verify the new API.

Add another request (Subscribe) to the new collection (gNMI)

Duplicate the previous request (Capabilities).
Rename it to Subscribe to interfaces state.
Select the RPC Subcribe of the gNMI service.
Copy this in the message (update the target with the SN of your device):

{
    "subscribe": {
        "encoding": "JSON",
        "mode": "STREAM",
        "prefix": {
            "target": "BAD032986065E8DC14CBB6472EC314A6"
        },
        "subscription": [
            {
                "path": {
                    "elem": [
                        {
                            "name": "interfaces"
                        },
                        {
                            "name": "interface"
                        },
                        {
                            "name": "state"
                        }
                       ],
                    "origin": "openconfig"
                }
            }
        ]
    }
}

Click on Invoke
Click on Send

Save this request.