See also questions close to this topic

• Whats missing on my Ruby 'Inverse Of' relationship

  I know this topic has been addressed, but I have been at this for 2 days and I'm just stuck. I know inverse of does not create a new query, so should I use another method?

  Question: How to set up an 'inverse of' with a has_one, belongs_to situation & same class..

  Explanation: A user 'has_one :spouse' and 'belongs_to :spouse_from'. They are inverse of each other. When a User signs up, they can invite their significant other. For Example

  1. user_a invites & creates user_b
  2. user_b.spouse_id is set to user_a.id
  3. In a separate method I want to be able to update like.. user_a.spouse_id = user_a.spouse.id

  The only association that works at this point is user_b.spouse.

   Class User
    has_one :spouse, class_name: 'User', foreign_key: :spouse_id, dependent: :nullify, inverse_of: :spouse_from
  
  
    belongs_to :spouse_from, class_name: 'User', foreign_key: :spouse_id, inverse_of: :spouse, optional: true
  
• Library functions in Inspec Test

  Team --

  I have a ruby library helper in which I have defined multiple functions/methods. How do I reference those in Chef Inspec tests?

  def interface_name
    # some code with logic
  end
  

  In my specific use case, I am checking to see if a custom networking device was specified as a JSON parameter, and if it was, I am validating it make sure its real (incase they misspelled it) and also gathering its IP and state and other data as reported by Ohai

  This is what I have so far, but I'm not sure if this is correct

    describe file('/path/to/custom_attributes.json') do
      it { should exist }
      unless json('/path/to/custom_attributes.json').empty? do
        its(['networking']['interface_name']) { should_not be_empty }
        interface_name = file(json('/path/to/custom_attributes.json').params['networking']['interface_name'])
      end
    end
  
    describe file('/etc/NetworkManager/system-connections/wired_connection') do
      unless interface_name.empty?
        its('content') { should_not match(/^interface-name=wl.*/mx) }
      end
      its('content') { should match(%r{ca-cert=/etc/ssl/certs/ca-certificates\.crt}mx) }
      its('content') { should match(/id=\.corp.*type=ethernet.*autoconnect-priority=100.*dns-search=corp\.domain.com.*/mx) }
    end
  end
  

  The problem / question is that if I gather the parameter directly from the JSON file, then I am bypassing all the validation logic that I'm doing in the library, which defeats the purpose. So, how do I get access to that library function/method in the Inspec test?

  For reference, here is the function:

  def interface_name
    file = '/path/to/custom_attributes.json'
    if File.exist?(file) && !File.stat(file).zero?
      attributes = JSON.parse(File.read(file))
      device_name = attributes['networking']['interface_name']
      if device_name && !device_name.empty? && networking_devices.include?(device_name)
        interface = device_name
        Chef::Log.info("Valid custom interface provided, using \"#{device_name}\".")
      else
        Chef::Log.debug("Invalid interface (\"#{device_name}\") provided. Valid options are: \"#{networking_devices.keys}\"")
        interface = nil
      end
    else
      Chef::Log.debug('No custom interface provided.')
    end
    interface
  rescue JSON::ParserError
    nil
  end
  
• Writing structured facts

  I've wrote some ruby code which will run on a linux server and return details about the server as a fact. It does this by connecting to amazon and retrieving some json (it runs two separate commands one to retrieve a list of disks - e.g /dev/sda1, /dev/xvdb and then it maps this to a volumeID via another query).

  I've made some small amendments to the output and added some values I'm interested in. The code runs multiple times and returns multiple hashes (one for each disk - maybe I should merge them?). Anyway here's an example of a server which has two disks below (this is just some debug output):

  Hash is {"/dev/sda1"=>{"disk_mapping"=>"", "is_lvm_partitioned"=>"false", "volumeid"=>"vol1234"}}.
  Hash is {"/dev/xvdb1"=>{"disk_mapping"=>"xvdb1", "is_lvm_partitioned"=>"true", "volumeid"=>"vol5678"}}.
  

  The next thing I want to to is turn this into a structured fact (with the devices: /dev/sda1, /dev/xvdb1 as the "keys"). Here's a rough idea of how I've done it (I've skipped a lot of the irrelevant code).

  json_string = {
    "#{path}" => {
    "disk_mapping"       => "#{disk_mapping}",
    "is_lvm_partitioned" => "#{is_lvm_partitioned}",
    "volumeid"           => "#{getVolumes}"
    }
  }.to_json
  hash = JSON.parse(json_string)
  if hash.is_a? Hash then
    debug_msg("Hash is #{hash}.")
    hash["#{path}"].each do |key, child|
      debug_msg("Setting key: #{key} child: #{child}.")
    end
  end
  

  I've never really wrote any ruby before so this is copied from multiple places, but besides aggregated facts I can't find a way to do this; I've tried to do something like this:

  Facter.add(:test["#{path}"]["#{key}"]) do
    setcode do
      #{child}
    end
  end
  

  So I guess in order I want to know:

  1. Should I merge the hash somehow? I originally assumed I did but found this incredibly hard due to not knowing how many hash's I'd have.
  2. Should I be using an aggregated fact or a "standard" one?
  3. How do I retain the structure of the hash and then call it with a single query (e.g facts test).
  4. Any examples which are similar to my code (the puppet ones I've found quite hard to follow).

  Here's what I'm looking for at the end:

  [root@blah ~]# facter test
  {
    /dev/sda1 => {
      disk_mapping => "",
      is_lvm_partitioned => "false",
      volumeid => "vol1234"
    },
    /dev/xvdb => {
      disk_mapping => "xvdb1",
      is_lvm_partitioned => "true",
      volumeid => "vol5678"
    }
  }
  

  Thanks.
• How can I speed up the routing process in OSMNX?

  Say I have two taxi orders with Origin1、Destination1 and Origin2、Destination2(O1,O2,D1,D2). I want to calculate the possibility of ridesharing, so I need the path between two different points. And, here's my code:

  def path_time(point1, point2):
      path = ox.distance.shortest_path(road, point1, point2, weight='travel_time')
      if path is None:
          #If there isn't a path, a big weight will be set, and it won't be selected during the matching process.
          route_time = 9999
      else:
          route_time = int(sum(ox.utils_graph.get_route_edge_attributes(road, path, "travel_time")))
      return route_time,path
  

  Since there is four points, I need to do this six times, where tp means travel path :

  tpO1O2 = path_time(O1,O2)
  tpO1D1 = path_time(O1,D1)
  tpO1D2 = path_time(O1,D2)
  tpO2D1 = path_time(O2,D1)
  tpO2D2 = path_time(O2,D2)
  tpD1D2 = path_time(D1,D2)
  

  It's okay if I only have two points, but I got a 2 million order set, and each order has hundreds of potential matched orders. So this will take me a lot of time.

  Does anyone knows how can I speed up this process? Thank you!
• How to properly plot a tree (27k nodes) using a circular tree / leave layout

  I have this (unbalanced) tree with 27k+ nodes. It is an hierachy. Now I would to plot it as such to obtain a plot something like this (no idea how you would describe it, but I would call it a circular leave tree...?

  

  However, I am unable to achieve such a result unfortunately. I have already tried igraph, Networkx, Maltego, Graphviz, Gephi. Hopefully someone can help me / give me tips & tricks or hints.

  Maltego

  Gives me quiet easily the following. However I cannot export it to pdf. Furthermore it has this wierd expansion on the top going to the left. I would be able to 'manually' (minimize) move it. However that is not what I would like.

  This is btw in my view (with the manual fix) the best result. But I cannot export it to vector or high-res image.

  

  igraph

  import igraph as ig
  bigGraphAsTupleList = (('a','b'),('b','c'),('b','d'), ..., ('c','e'))
  g = ig.Graph.TupleList(bigGraphAsTupleList)
  layout = g.layout("rt_circular") #fr (fruchterman reingold), tree, circle, rt_circular (reingold_tilford_circular)
  # bbox = size of picture
  ig.plot(g,layout=layout,bbox=(10000,10000),target='mygraph.png')
  

  This gives me something like below.

  reingold tilford circular

  fruchterman reingold (so much overlap of nodes and connections)

  Networkx

  import networkx as nx
  import matplotlib.pyplot as plt
  G = nx.Graph()
  G.add_edge(...) #build graph
  nx.draw_circular(G) #nx.draw_spring(G) #nx.draw_spectral
  plt.draw()
  plt.show()
  

  

  Graphviz (via Networkx)

  Also a wierd result a bit similar as the next one Maltego. However

  import networkx as nx
  import matplotlib.pyplot as plt
  import pydot
  from networkx.drawing.nx_pydot import graphviz_layout
  G = nx.Graph()
  G.add_edge(...) #build graph
  pos = graphviz_layout(G, prog="circo")
  plt.figure(1,figsize=(60,60))
  nx.draw(G, pos,node_size=10)
  plt.show(block=False)
  plt.savefig("Graph.png", format="PNG")