/v1/graph/nodemetrics method unresponsive

[jmarbach]

trafficstars

Background

I am trying to determine the Betweenness centrality of my node by using the REST API endpoint /v1/graph/nodemetrics and instead my node returns NoMethodError.

Endpoint: https://api.lightning.community/#v1-graph-nodemetrics

Your environment

• lnd 0.15.0-beta

Steps to reproduce

In Ruby:

require 'faraday'

class LndAPI
  attr_accessor :host, :port, :macaroon

  def initialize(host:, port:, macaroon:)
    @host = host
    @port = port
    @macaroon = macaroon # hex needed for auth header
    @conn = Faraday.new(
      url: "https://#{@host}:#{@port}",
      headers: {'Grpc-Metadata-macaroon' => @macaroon}
    ) do |faraday|
      faraday.response :raise_error
    end
  end

  def graph_nodemetrics(metric_types)
    if metric_types == nil
      metric_types = '1'
    else
      metric_types = metric_types
    end
    metric_types = metric_types.to_s

    begin
      request_response = @conn.get("/v1/graph/nodemetrics", { types: metric_types })
    rescue => e
      puts "LND API Error!"
      puts e.response[:status]   #=> 404
      puts e.response[:headers]  #=> { ... }
      puts e.response[:body]     #=> "..."

      parsed_response_body = JSON.parse(e.response[:body])
      return parsed_response_body
    else
      puts "LND API Success!"
      parsed_response_body = JSON.parse(request_response.body)
      return parsed_response_body
    end
  end
  
  def parse(response)
    JSON.parse(response.body)
  end
end

node = ...
lnd = LndAPI.new(host:node.host, port:node.port, macaroon:node.macaroon_hex)
lnd_response = lnd.graph_nodemetrics(1)

Expected behaviour

I expected a response with the field betweenness_centrality showing my node's betweenness.

Actual behaviour

Response:

NoMethodError (undefined method `[]' for nil:NilClass)

[saubyk]

@jmarbach couple of questions for you:

• have you tried the same rpc via the cli?
• try it with LND v0.15.1. I am able to get a response on the cli on 0.15.1

Also note that nodemetrics will return the betweenness metric for all the nodes on the graph, not just yours. You'll need to search for your node from the response. We can possibly improve this rpc by adding a node pubkey argument.

[guggero]

Closing due to inactivity.