sort requirement files in alphabetical order

This makes code more readable, and can check whether specific library
in the requirement files easily. We also enforce the check in pep8.

Change-Id: I98be4ab6c46301fabe8badc00dd3a60333473414
Closes-Bug: #1285478

requirements.txt

@@ -1,10 +1,9 @@
-pbr>=0.6,<1.0
-
-Flask>=0.10,<1.0
 Flask-Gravatar
+Flask>=0.10,<1.0
 iso8601>=0.1.8
 oslo.config>=1.2.0
 paramiko>=1.8.0
+pbr>=0.6,<1.0
 psutil>=1.1.1
 PyGithub
 python-memcached>=1.48

test-requirements.txt

@@ -1,9 +1,8 @@
-hacking>=0.8.0,<0.9
-
 coverage>=3.6
 discover
 docutils==0.9.1
 fixtures>=0.3.14
+hacking>=0.8.0,<0.9
 jsonschema>=2.0.0,<3.0.0
 mock>=1.0
 python-subunit

tools/requirements_style_check.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+#
+# Enforce the requirement that dependencies are listed in the input
+# files in alphabetical order.
+
+# FIXME(dhellmann): This doesn't deal with URL requirements very
+# well. We should probably sort those on the egg-name, rather than the
+# full line.
+
+function check_file() {
+    typeset f=$1
+
+    # We don't care about comment lines.
+    grep -v '^#' $f > ${f}.unsorted
+    sort -i -f ${f}.unsorted > ${f}.sorted
+    diff -c ${f}.unsorted ${f}.sorted
+    rc=$?
+    rm -f ${f}.sorted ${f}.unsorted
+    return $rc
+}
+
+exit_code=0
+for filename in $@
+do
+    check_file $filename
+    if [ $? -ne 0 ]
+    then
+        echo "Please list requirements in $filename in alphabetical order" 1>&2
+        exit_code=1
+    fi
+done
+exit $exit_code

tox.ini

@@ -17,6 +17,7 @@ distribute = false
 
 [testenv:pep8]
 commands = flake8
+           {toxinidir}/tools/requirements_style_check.sh requirements.txt test-requirements.txt
 distribute = false
 
 [testenv:venv]