Merge pull request #37 from inaka/igaray.27.prefer_git_protocol

[Closes #27] Prefer git protocol for deps

README.md

@@ -54,6 +54,7 @@ Table of Contents:
  * [Lock your dependencies](#lock-your-dependencies)
  * [Loud errors](#loud-errors)
  * [Properly use logging levels](#properly-use-logging-levels)
+ * [Prefer the git protocol when specifying dependency locations](#prefer-the-git-protocol-over-others-when-specifying-dependency-urls)
 * [Suggestions & Great Ideas](#suggestions--great-ideas)
  * [CamelCase over Under_Score](#camelcase-over-under_score)
  * [Prefer shorter (but still meaningful) variable names](#prefer-shorter-but-still-meaningful-variable-names)
@@ -422,6 +423,18 @@ Following this rule you also get the benefits that `-opaque` types provide, for
  * ``alert``: _There is no rule on when to use this level_
  * ``emergency``: _There is no rule on when to use this level_
 
+##### Prefer the git protocol over others when specifying dependency URLs
+> When specifying dependencies in erlang.mk Makefils or rebar.config, prefer using the git protocol to download the dependency repository.
+
+*Examples*: [makefile example](src/dependency_protocol/dep_protocol.makefile) [rebar example](src/dependency_protocol/dep_protocol.config)
+
+*Reasoning*: SSH requires authentication.
+https may require authentication (bitbucket does, github doesn't), but sometimes doesn't.
+In addition, https is chatty compared to the git protocol, optimized for cloning repos.
+The git protocol's main disadvantage is that it doesn't support authentication, which is a plus for CI systems.
+
+* [Git on the Server - The Protocols](http:https://git-scm.com/book/ch4-1.html)
+
 ## Suggestions & Great Ideas
 
 Things that should be considered when writing code, but do not cause a PR rejection, or are too vague to consistently enforce.

src/dependency_protocol/dep_protocol.config

@@ -0,0 +1,14 @@
+```erlang
+%% bad
+{deps,
+ [{lager, "2.*", {git, "[email protected]:basho/lager.git", "2.0.0"}},
+ {jiffy, "0.*", {git, "https://github.com:davisp/jiffy.git", "0.13.3"}}
+}.
+
+%% good
+{deps,
+ {lager, "2.*", {git, "git:https://github.com/basho/lager.git", "2.0.0"}},
+ {jiffy, "0.*", {git, "git:https://github.com:davisp/jiffy.git", "0.13.3"}}
+}.
+```
+

src/dependency_protocol/dep_protocol.makefile

@@ -0,0 +1,11 @@
+PROJECT = myproject
+
+DEPS = cowboy lager jiffy
+# bad
+dep_lager = git https://github.com/basho/lager.git 2.0.1
+dep_jiffy = git https://github.com/davisp/jiffy.git 0.13.3
+
+# good
+dep_lager = git git:https://github.com/basho/lager.git 2.0.1
+dep_jiffy = git git:https://github.com/davisp/jiffy.git 0.13.3
+