How to implement an anonymous subgraph

[csghuser]

Hello, many thanks for this library!

I have a question which is duplicate of this issue here:

#9 (comment)

In a manual graphviz chart I have the following setup.

At the top of my graph I have defined:

  newrank=true;

As part of my graph I have the following anonymous graph:

{ rank=same; some_node_1; some_node_2; }  # How to inject this line?

This works, however similar to the issue linked above, how do I accomplish this in gographviz?

[awalterschulze]

Could you try parsing it with gographviz and reverse engineering it that way?
Please let me know what you find, so that I can try to help.

[csghuser]

I managed to get an example of this working, before and after the changes.

The graph for this example has been borrowed from https://stackoverflow.com/q/6824431
Also the answer as well 🙂

g, _ := gographviz.Read([]byte(`digraph G {
    subgraph cluster1 {
        label="Local Datacenter";
        router1;
        host1;
    }
    subgraph cluster2 {
        label="Remote Datacenter";
        router2;
        host2;
    }
    router1 -> router2;
    router2 -> host2;
    router1 -> host1;
}`))
s := g.String()
fmt.Println(s)

This produces the following:

Where as we want them on the same level, so..... we add the following section to the code above:

g.AddAttr("G", "newrank", "true")
g.AddSubGraph("G", "force_node_same_level", map[string]string{"rank": "same"})
g.AddNode("force_node_same_level", "router1", nil)
g.AddNode("force_node_same_level", "router2", nil)
s := g.String()
fmt.Println(s)

Which gives us:

The dot file looks like this :

digraph G {
  newrank=true;
  router1->router2;
  router2->host2;
  router1->host1;
  subgraph cluster1 {
  label="Local Datacenter";
  host1;
  router1;

}
;
  subgraph cluster2 {
  label="Remote Datacenter";
  host2;
  router2;

}
;
  subgraph force_node_same_level {
  rank=same;
  router1;
  router2;

}
;

}

I was struggling to work out out to add the subgraph above but it's actually fairly straightforward. Hopefully this helps someone else! 🙂

[awalterschulze]

Thank you so much.
This is SUPER helpful.
I really appreciate the effort of not only finding the answer, but documenting it so well for others (including me).
Great job.

[awalterschulze]

I am closing the issue, but I also added a link to this issue from the Readme, to make it easier for other users to find.