Add copyright checker to tox

+ Only looks at files edited since HEAD~.
+ Only checks files of whitelisted extensions.
+ Distinguishes missing and outdated copyrights.
+ Any line with "Copyright" substring can work.
+ Many copyright lines are tolerated, if at least one has correct year.
+ Voting.

Change-Id: I2cda0459cb191eeec7aada69c508973568039d87
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

2 files changed, 113 insertions, 5 deletions

diff --git a/resources/libraries/bash/entry/check/copyright.sh b/resources/libraries/bash/entry/check/copyright.sh
new file mode 100644
index 0000000000..91e89bd12e
--- /dev/null
+++ b/resources/libraries/bash/entry/check/copyright.sh
@@ -0,0 +1,106 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -exuo pipefail
+
+# This file should be executed from tox, as the assumed working directory
+# is different from where this file is located.
+# This file does not have executable flag nor shebang,
+# to dissuade non-tox callers.
+
+# This script examines any file edited since HEAD~ (filtered by extension),
+# and fails if no line with "Copyright" and the current year is found.
+# The list of offending files is written to copyright.log (overwriting).
+# The log also specifies whether the copyright is missing or outdated.
+
+# As copyright notice usually gives readers also a license to use it,
+# any file without copyright is potentially unusable (by non-authors).
+# In the interest of open source code reuse, CSIT wants any content
+# to be available under appropriate license, which depends on whether the file
+# is deemed "code" (Apache License, Version 2.0), "documentation"
+# (Creative Commons Attribution 4.0 International), or something else.
+# Note that this checker does not check licenses,
+# it assumes any copyright notice includes the correct data
+# (all contributing people/organizations, all applicabe licenses).
+
+# Unfortunately, some file types are not designed to hold copyright notice,
+# or at least the correct way to include it is not known yet.
+# Or the file in question is processed by code which is not ready
+# for (otherwise allowed) comment lines holding the copyright.
+# That is why currently we need to explicitly whitelist filename patterns.
+
+# TODO: Figure out how to add copyright notice into .svg files.
+#       Do the usual .xml style comments work?
+# TODO: Make the code processing text files (example: VPP_REPO_URL)
+#       tolerate comment lines.
+# TODO: Verify more extensions are safe to whitelist (.virl)
+#       and that tools processing some format allows comments (.json).
+# TODO: Ultimately remove filtering to start checking every file.
+
+# "set -eu" handles failures from the following two lines.
+BASH_CHECKS_DIR="$(dirname $(readlink -e "${BASH_SOURCE[0]}"))"
+BASH_FUNCTION_DIR="$(readlink -e "${BASH_CHECKS_DIR}/../../function")"
+source "${BASH_FUNCTION_DIR}/common.sh" || {
+    echo "Source failed." >&2
+    exit 1
+}
+
+fulldate=$(date)
+year="${fulldate##* }"
+# Regexp selecting only files we expect to allow copyright.
+# Start from an array, each item is to be prepended by ., appended by $,
+# and joined by |.
+extensions_array=("gitgnore" "ini" "md" "py" "robot" "rst" "sh" "txt" "yaml")
+pattern=""
+for extension in "${extensions_array[@]}"; do
+    pattern+="\.${extension}"'$'"\|"
+done
+# One more "extension" just to avoid trailing pipe.
+pattern+="/Dockerfile"'$'
+# Get array of edited files.
+# Commands to expand, pipe has to be left out.
+cmd1="git diff --name-only HEAD~"
+cmd2="grep \"${pattern}\""
+# When calling, commands has to be without quotes.
+readarray -t file_array <<<$(${cmd1} | ${cmd2}) || {
+    # We need to tolerate changes that only edit other files.
+    errors=$(${cmd1} | ${cmd2} 2>&1 || true)
+    if [[ "${errors}" ]]; then
+        # TODO: do we need to echo errors?
+        die "Failure at getting list of files to check copyright in."
+    fi
+    # Empty file array is accepted.
+    # Accidentally, if "git diff" fails, we still proceed with empty array.
+}
+logfile="copyright.log"
+truncate --size 0 "${logfile}" || die "truncate failed"
+# Temporary +x so big changes do not spam.
+set +x
+for filename in "${file_array[@]}"; do
+    if ! fgrep -q "Copyright" "${filename}"; then
+        echo "No copyright found in file: ${filename}" >> "${logfile}"
+    elif ! fgrep "Copyright" "${filename}" | fgrep -q "${year}"; then
+        echo "No year ${year} copyright found in: ${filename}" >> "${logfile}"
+    fi
+done
+set -x
+if [ -s "${logfile}" ]; then
+    warn "Copyright violations detected."
+    # TODO: Disable when output size does more harm than good.
+    cat "${logfile}" >&2
+    warn
+    warn "Copyright checker: FAIL"
+    exit 1
+fi
+warn
+warn "Copyright checker: PASS"
diff --git a/tox.ini b/tox.ini
index 5fc3172c1a..a09a90f72b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,7 +25,7 @@
 # will execute only checks defined in "pylint" tox environment.
 
 [tox]
-envlist = new_line_length, line_length, autogen, pylint
+envlist = copyright, new_line_length, line_length, autogen, pylint
 # The following is needed as tox requires setup.py by default.
 skipsdist = true
 # Just a shorthand to avoid long lines.
@@ -56,17 +56,19 @@ whitelist_externals = /bin/bash
 # the checker has to remain non-voting.
 commands = bash -c "bash {[tox]checker_dir}/new_line.sh || true"
 
+[testenv:copyright]
+whitelist_externals = /bin/bash
+commands = bash {[tox]checker_dir}/copyright.sh
+
 [testenv:autogen]
 whitelist_externals = /bin/bash
 setenv = PYTHONPATH = {toxinidir}
 commands = bash {[tox]checker_dir}/autogen.sh
 
+# TODO: Migrate current docs check here.
+# TODO: Create voting "pylint violations should not increase" checker.
 # TODO: Create voting checker to reject suites with Force Tags of other suite.
 # TODO: Create voting checker against tags not in tag_documentation.rst file.
-# TODO: Create voting "pylint violations should not increase" checker.
-# TODO: Figure out how to make new_line checker voting.
-# TODO: Migrate current docs check here.
-# TODO: Create license checker.
 # TODO: Create Robot suite Documentation checker (backslash if not next mark).
 # TODO: Create .yaml specific checker, so people can override long line check.
 # TODO: Create .rst specific checker, if there is one allowing