fixes bug 1389463 - create architecture diagram using dot

This redoes the architecture diagram using graphviz and dot notation. It's not
the bestest thing in the world, but it's editable without additional tools and
it seems good for now.

docs/conf.py

@@ -28,7 +28,9 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = []
+extensions = [
+    'sphinx.ext.graphviz'
+]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']

docs/gettingstarted.rst

@@ -242,13 +242,62 @@ environment, put it in ``my.env``.
 General architecture
 ====================
 
+.. graphviz::
+
+   digraph G {
+      rankdir=LR;
+
+      client [shape=box3d, label="firefox"];
+
+      subgraph antpig {
+         rank=same;
+
+         antenna [shape=rect, label="antenna"];
+         pigeon [shape=cds, label="pigeon"];
+      }
+
+      subgraph stores {
+         rank=same;
+
+         aws [shape=tab, label="S3", style=filled, fillcolor=gray];
+         postgres [shape=tab, label="Postgres", style=filled, fillcolor=gray];
+         elasticsearch [shape=tab, label="Elasticsearch", style=filled, fillcolor=gray];
+         telemetry [shape=tab, label="Telemetry (S3)", style=filled, fillcolor=gray];
+         rabbitmq [shape=tab, label="RMQ", style=filled, fillcolor=gray];
+      }
+
+      subgraph processing {
+         rank=same;
+
+         processor [shape=rect, label="processor"];
+         crontabber [shape=rect, label="crontabber"];
+      }
+
+      webapp [shape=rect, label="webapp"];
+
+      client -> antenna [label="HTTP"];
+      antenna -> aws [label="save raw"];
+
+      aws -> pigeon [label="S3:PutObject"];
+      pigeon -> rabbitmq [label="crash id for processing"];
+
+      rabbitmq -> processor [label="crash id"];
+      aws -> processor [label="load raw"];
+      processor -> { aws, postgres, elasticsearch, telemetry } [label="save processed"];
+
+      postgres -> webapp;
+      aws -> webapp [label="load raw,processed"];
+      elasticsearch -> webapp [label="search"];
+
+      { rank=min; client; }
+   }
+
+
 .. Warning::
 
    August 17th, 2017. Everything below this point needs to be updated.
 
 
-.. image:: block-diagram.png
-
 Arrows direction represents the flow of interesting information (crashes,
 authentication assertions, cached values), not trivia like acks.