feat(test/compare.sh): Add verification

Signed-off-by: Oliver Gondža <ogondza@gmail.com>

Author: olivergondza

README.md

@@ -184,13 +184,14 @@ Note: most of the resource outputs are given in 3 file types: `.json`, `.yaml`,
 
 ## Testing
 
-You can run the script locally from your workstation.
-To do that you need an OpenShift cluster and you will have to install the Red Hat GitOps Operator.
-Then you can run the script like this:
+To do that you need an OpenShift cluster, and you will have to install the Red Hat GitOps Operator.
+Then you can test how your changes affects gathered data:
 
 ```shell
-chmod +x ./gather_gitops.sh
-./gather_gitops.sh --base-collection-path .
+# You may need to create the repository on quay.io manually to make sure it is public
+make REGISTRY_USERNAME=my-non-production-org CONTAINER_IMAGE_TAG="$(git rev-parse HEAD)" push
+# Note some differences are expected, like few lines in rapidly populated logs
+./test/compare.sh registry.redhat.io/openshift-gitops-1/must-gather-rhel8:"$SOME_OLD_VERSION" quay.io/my-non-production-org/gitops-must-gather:"$(git rev-parse HEAD)"
 ```
 
 Last but not least, please make sure you run `make lint` before pushing new changes.

test/compare.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+# https://github.com/olivergondza/bash-strict-mode
+set -eEuo pipefail
+trap 's=$?; echo >&2 "$0: Error on line "$LINENO": $BASH_COMMAND"; exit $s' ERR
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
+
+function main() {
+    if [[ $# -ne 2 ]]; then
+        echo >&2 "Usage: $0 [IMAGE_A] [IMAGE_B]"
+        exit 1
+    fi
+    local img_a=$1
+    local img_b=$2
+
+    inv_a="$(mktemp -d gitops-must-gather-A-XXXX)"
+    inv_b="$(mktemp -d gitops-must-gather-B-XXXX)"
+    trap "rm -rf '${inv_a}' '${inv_b}'" EXIT
+
+    gather "$img_a" "$inv_a"
+    gather "$img_b" "$inv_b"
+
+    diff --color=auto --recursive \
+        --ignore-matching-lines="resourceVersion: " \
+        "${inv_a}" "${inv_b}"
+}
+
+function gather() {
+    image=$1
+    dir=$2
+
+    if ! oc adm must-gather --image="$image" --dest-dir="${dir}" 2>&1 | tee "${dir}/oc-adm-output.log"; then
+        echo >&2 "Failed gathering for $image"
+        return 1
+    fi
+
+    sanitize "$image" "$dir"
+}
+
+function sanitize() {
+    image=$1
+    dir=$2
+
+    # Unify names of the directories its name is based on image name
+    mv "$dir"/*-sha256-* "$dir/__RESOURCES__"
+
+    # In log files, drop image name, generated resource names, timestamp, line numbers, and transfer metrics
+    sed -i -r \
+        -e "s~${image}~__IMAGE_TAG__~g" \
+        -e "s~must-gather-[a-z0-9]{5}~must-gather-XXXXX~g" \
+        -e 's~[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]+Z~__TIMESTAMP__~g' \
+        -e 's~gather_gitops:[0-9]+~gather_gitops:LL~g' \
+        -e '/total size is .* speedup is .*/d' \
+        -e '/sent .* received .* bytes\/sec/d' \
+        "$dir/oc-adm-output.log" "$dir/must-gather.logs" "$dir/__RESOURCES__/gather.logs" "$dir/__RESOURCES__/gather_gitops.log"
+
+    # Timestamps are not going to match, just test there is the same number of them
+    wc -l < "$dir/timestamp" > "$dir/timestamp"
+    wc -l < "$dir/__RESOURCES__/timestamp" > "$dir/__RESOURCES__/timestamp"
+}
+
+main "$@"