Find differences in Flux HelmRelease versions

helmrelease-diff.sh

#!/bin/bash

set -euo pipefail

info() {
    echo "INFO - $*"
}

warn() {
    echo "WARNING - $*"
}

err() {
    echo "ERROR - $*" >>/dev/stderr
    return 1
}

render() {
    outfile="$1"
    version="$2"

    if [[ "$repo" =~ oci://.+ ]]; then
        info "OCI repository detected"
        if [ "$version" == "latest" ]; then
            yq '.spec.values' "$releasefile" | helm template "$releasename" -n "$namespace" "$repo/$chart" --values - > "$outfile"
        else
            yq '.spec.values' "$releasefile" | helm template "$releasename" -n "$namespace" "$repo/$chart" --version "$version" --values - > "$outfile"
        fi
    else
        if [ "$version" == "latest" ]; then
            yq '.spec.values' "$releasefile" | helm template "$releasename" -n "$namespace" --repo "$repo" "$chart" --values - > "$outfile"
        else
            yq '.spec.values' "$releasefile" | helm template "$releasename" -n "$namespace" --repo "$repo" "$chart" --version "$version" --values - > "$outfile"
        fi
    fi

    # Remove comments
    sed -i '/^#/d' "$outfile"
    info "Chart manifests has been written to $outfile"
}

releasefile="$(realpath "$1")"
repofile="$(realpath "$2")"
old_version="${3:-"current"}"
new_version="${4:-"latest"}"

_oldfile="/tmp/old-template.yaml"
_newfile="/tmp/new-template.yaml"
_diffile="/tmp/templates.diff"

releasename="$(yq '.metadata.name' "$releasefile")"
namespace="$(yq '.metadata.namespace // "default"' "$releasefile")"
chart="$(yq '.spec.chart.spec.chart' "$releasefile")"

info "Chart: $chart"

repo="$(yq '.spec.url' "$repofile")"

info "Repository: $repo"

if [ "$old_version" == "current" ]; then
    old_version="$(yq '.spec.chart.spec.version' "$releasefile")"
fi

info "Version change: $old_version to $new_version"

if [ "$(yq '.spec.postRenderers' "$releasefile")" != "null" ]; then
    warn "postrenderer found - ignoring"
fi

# Change directory to fix `helm template` when $chart is a directory/file
(
    cd "$(mktemp -d)" || err "Error moving to temporary directory"

    # Render the templates
    render "$_oldfile" "$old_version" &
    _old_pid=$!

    render "$_newfile" "$new_version" &
    _new_pid=$!

    wait $_old_pid $_new_pid
)

if ! diff $_oldfile $_newfile > $_diffile; then
    info "Manifest diff written to $_diffile"
else
    info "No changes found"
fi