Merge pull request #41 from mboersma/add-changelog

feat(_scripts): add CHANGELOG.md generator script

Author: mboersma

_scripts/generate-changelog.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# vim: et tw=0 sw=4 ts=4
+
+REPOROOT=${REPOROOT:=https://github.com/deis/workflow-cli}
+TYPES=${TYPES:=feat(;Features fix(;Fixes docs(;Documentation chore(;Maintenance}
+
+usage() {
+    echo "Usage: $0 <from> [to]
+
+The REPOROOT and TYPES variables may be used to customize what links are
+generated and what is scraped from the commit logs. Current settings are:
+
+    REPOROOT=$REPOROOT
+    TYPES=$TYPES
+"
+}
+
+# Print the information scraped from git
+retrieve() {
+    while read -r commit hash message; do
+        # Extract the subsystem where type(subsystem): message
+        SUBSYSTEM=$(echo "$message" | cut -d'(' -f2 | cut -d')' -f1 | sed 's/\*/\(all\)/g')
+        # Extract the message where type(subsystem): message
+        MESSAGE=$(echo "$message" | awk -F ")" '{ print $2}' | sed 's/://' | cut -f2- -d' ')
+        # Generate a link to the full legal commit on GitHub
+        LINK="$REPOROOT/commit/$hash"
+        # Echo all this in a way that makes the commit hash and message a link
+        # to the commit in markdown
+        echo ' -' "[\`$commit\`]($LINK)" "$SUBSYSTEM": "$MESSAGE"
+    done < <(git --no-pager log --oneline --merges --oneline --format="%h %H %b" --grep="$1" "$FROM".."$TO")
+    # Scrape the information from git
+}
+
+# Wrap feature type and show its relevant commits
+subheading() {
+    echo "#### $1"
+    echo
+    retrieve "$2"
+    echo
+}
+
+main() {
+    # Print usage summary if user didn't specify a beginning
+    if [ -z "$1" ]; then
+        usage
+        exit 1
+    fi
+
+    FROM=$1
+    TO=${2:-"HEAD"}
+
+    printf "### %s -> %s\n\n" "$FROM" "$TO"
+
+    # Iterate over the types of messages specified
+    for LEGALTYPE in $TYPES; do
+        SHORT=$(echo "$LEGALTYPE" | cut -f1 -d';')
+        LONG=$(echo "$LEGALTYPE" | cut -f2 -d';')
+        subheading "$LONG" "$SHORT"
+    done
+}
+
+if [ $SHLVL -eq 2 ]; then
+    # If this is being run as a command
+    main "$@"
+else
+    # Otherwise this is being sourced
+    unset -f main
+    unset -f usage
+fi