round-robin.sh: Rework handling of base-artifacts history

Instead of keeping builds for regressions only, keep history for
all successful commits (update_baseline == force is successful by
definition).  Trim ancient history (delete non-essential artifacts)
to keep size manageable.

This will store adequate history of builds for [upcoming] dashboard.

Change-Id: Iaa129a5c7f41e9c3ca9f1829ba668ea972792741

1 files changed, 32 insertions, 41 deletions

diff --git a/round-robin.sh b/round-robin.sh
index ab7b10bb..86161d8f 100644
--- a/round-robin.sh
+++ b/round-robin.sh
@@ -763,46 +763,35 @@ update_baseline ()
     (
     set -euf -o pipefail
 
-    local amend=""
-
     if [ x"${rr[update_baseline]}" = x"ignore" ]; then
 	return
-    elif [ x"${rr[update_baseline]}" = x"init" ]; then
-	amend="--amend"
-    else
-	# ${rr[update_baseline]} == onsuccess, force
-	local prev_head=""
-
-	# We discard baseline entries for results worse or same than
-	# the current one, but keep entries for results that are better
-	# (so that we have a record of pending regressions).
-	while true; do
-	    ${rr[no_regression_p]} base-artifacts ${rr[top_artifacts]} &
-	    if ! wait $!; then
-		break
-	    fi
-
-	    prev_head=""
-	    if git -C base-artifacts rev-parse HEAD^ >/dev/null 2>&1; then
-		# For every regression we want to keep artifacts for the first-bad
-		# build, so reset to the most relevant regression (marked by reset-baseline).
-		if [ -f base-artifacts/reset-baseline ] \
-		       && [ x"${rr[update_baseline]}" = x"onsuccess" ]; then
-		    prev_head=$(git -C base-artifacts rev-parse HEAD)
-		fi
-		git -C base-artifacts reset --hard HEAD^
-	    else
-		# We got to the beginning of git history, so amend the current
-		# commit.  The initial state of baseline is "empty" branch,
-		# which we treat as worst possible in ${rr[no_regression_p]}().
-		amend="--amend"
-		break
-	    fi
-	done
+    fi
 
-	if [ x"$prev_head" != x"" ]; then
-	    git -C base-artifacts reset --hard $prev_head
-	fi
+    # - For the last 100 builds: keep everything
+    # - For the rest of the builds: delete non-essential artifacts
+    # - NN-<step> directories are non-essential, the rest -- jenkins/,
+    #   dashboard/, etc. -- are essential.
+    local old_commit
+    old_commit=$(git -C base-artifacts rev-parse HEAD~100 \
+		     2>/dev/null)
+
+    if [ x"$old_commit" != x"" ]; then
+	local head
+	head=$(git -C base-artifacts rev-parse HEAD)
+
+	# Remove directories starting with number from $old_commit
+	# and older.
+	git -C base-artifacts checkout -detach $old_commit
+	git -C base-artifacts filter-repo --force \
+	    --invert-paths --path-regex '^[0-9].*' \
+	    --refs HEAD
+
+	# Reparent history on the new version of $old_commit.
+	local new_old_commit
+	new_old_commit=$(git -C base-artifacts rev-parse HEAD)
+	git -C base-artifacts checkout --detach $head
+	git -C base-artifacts replace $old_commit $new_old_commit
+	git -C base-artifacts filter-repo --force --refs HEAD
     fi
 
     # Rsync current artifacts.  Make sure to use -I rsync option since
@@ -813,11 +802,13 @@ update_baseline ()
     # in base-artifacts.git repo (though they will be uploaded to jenkins).
     rsync -aI --del --exclude /.git ${rr[top_artifacts]}/ base-artifacts/
 
-    local rev_count
-    if [ x"$amend" = x"" ]; then
-	rev_count=$(git -C base-artifacts rev-list --count HEAD)
-    else
+    local rev_count amend=""
+
+    if [ x"${rr[update_baseline]}" = x"init" ]; then
 	rev_count="0"
+	amend="--amend"
+    else
+	rev_count=$(git -C base-artifacts rev-list --count HEAD)
     fi
 
     local msg_title="$rev_count: ${rr[update_baseline]}"