commit 5f9808d1d799c39f014ce3175779123aabc6058b
parent 47d69d981e63200c519e9bd9d358da9887c3c7ae
Author: Nick Mathewson <nickm@torproject.org>
Date: Tue, 17 Dec 2019 09:39:50 -0500
Merge remote-tracking branch 'tor-github/pr/1596'
Diffstat:
3 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/changes/ticket32206 b/changes/ticket32206
@@ -0,0 +1,3 @@
+ o Documentation:
+ - Create a high-level description of the long-term software
+ architecture goals. Closes ticket 32206.
diff --git a/src/arch_goals.md b/src/arch_goals.md
@@ -0,0 +1,31 @@
+@page arch_goals High level code design practices
+
+This page describes the high level design practices for Tor's code.
+This design is a long-term goal of what we want our code to look like,
+rather than a description of how it currently is.
+
+Overall, we want various parts of tor's code to interact with each
+other through a small number of interfaces.
+
+We want to avoid having "god objects" or "god modules". These are
+objects or modules that know far too much about other parts of the
+code. God objects/modules are generally recognized to be an
+antipattern of software design.
+
+Historically, there have been modules in tor that have tended toward
+becoming god modules. These include modules that help more
+specialized code communicate with the outside world: the configuration
+and control modules, for example. Others are modules that deal with
+global state, initialization, or shutdown.
+
+If a centralized module needs to invoke code in almost every other
+module in the system, it is better if it exports a small, general
+interface that other modules call. The centralized module should not
+explicitly call out to all the modules that interact with it.
+
+Instead, modules that interact with the centralized module should call
+registration interfaces. These interfaces allow modules to register
+handlers for things like configuration parsing and control command
+execution. (The config and control modules are examples of this.)
+Alternatively, registration can happen through statically initialized
+data structures. (The subsystem mechanism is an example of this.)
diff --git a/src/mainpage.md b/src/mainpage.md
@@ -29,6 +29,8 @@ Tor repository.
@subpage intro
+@subpage arch_goals
+
@subpage initialization
@subpage dataflow
