feat(ci): add fetch helm deps script (#4386)

* feat(ci): add fetch helm deps

* add some error handling

* require the command

* pretty output

.github/scripts/fetch_helm_deps.sh

@@ -0,0 +1,87 @@
+#!/bin/bash
+
+# require go-yq
+command -v go-yq >/dev/null 2>&1 || {
+    printf >&2 "%s\n" "❌ go-yq (https://github.com/mikefarah/yq) is not installed. Aborting."
+    exit 1
+}
+
+cache_path="./tgz_cache"
+
+mkdir -p "$cache_path"
+
+charts_ath="../../charts"
+
+trains=(
+    "enterprise"
+    "stable"
+    "incubator"
+    "dependency"
+)
+
+for train in "${trains[@]}"; do
+    for chart in $(ls "$charts_ath/$train"); do
+        deps=$(go-yq '.dependencies' "$charts_ath/$train/$chart/Chart.yaml")
+        length=$(echo "$deps" | go-yq '. | length')
+
+        echo "🔨 Processing <$chart>... Dependencies: $length"
+        echo ""
+
+        for idx in $(eval echo "{0..$length}"); do
+            curr_dep=$(echo "$deps" | pos="$idx" go-yq '.[env(pos)]')
+
+            if [ ! "$curr_dep" == null ]; then
+                name=$(echo "$curr_dep" | go-yq '.name')
+                version=$(echo "$curr_dep" | go-yq '.version')
+                repo=$(echo "$curr_dep" | go-yq '.repository')
+
+                echo "**********"
+                echo "🔗 Dependency: $name"
+                echo "🆚 Version: $version"
+                echo "🏠 Repository: $repo"
+                echo ""
+
+                if [ -f "$cache_path/$name-$version.tgz" ]; then
+                    echo "✅ Dependency exists in cache..."
+                else
+                    echo "🤷‍♂️ Dependency does not exists in cache..."
+
+                    repo_url="$repo/index.yaml"
+                    echo "🤖 Calculating URL..."
+                    dep_url=$(curl -s "$repo_url" | v="$version" n="$name" go-yq '.entries.[env(n)].[] | select (.version == env(v)) | .urls.[0]')
+
+                    echo ""
+                    echo "⏬ Downloading dependency $name-$version from $dep_url..."
+                    wget --quiet "$dep_url" -P "$cache_path/"
+                    if [ ! $? ]; then
+                        echo "❌ wget encountered an error..."
+                        exit 1
+                    fi
+
+                    if [ -f "$cache_path/$name-$version.tgz" ]; then
+                        echo "✅ Dependency Downloaded!"
+                    else
+                        echo "❌ Failed to download dependency"
+                        # Fail fast if a dep fails to download...
+                        exit 1
+                    fi
+                fi
+                echo ""
+
+                mkdir -p "$charts_ath/$train/$chart/charts"
+                echo "📝 Copying dependency <$name-$version.tgz> to <$charts_ath/$train/$chart/charts>..."
+                cp "$cache_path/$name-$version.tgz" "$charts_ath/$train/$chart/charts"
+
+                if [ -f "$cache_path/$name-$version.tgz" ]; then
+                    echo "✅ Dependency copied!"
+                    echo ""
+                else
+                    echo "❌ Failed to copy dependency"
+                    # Fail fast if a dep fails to copy...
+                    exit 1
+                fi
+            fi
+        done
+        echo "----------"
+    done
+done