From 19fab24b9c84115c8c1e85cbf112a2ef7327fa9d Mon Sep 17 00:00:00 2001
From: Guilhem Lettron <glettron@akamai.com>
Date: Fri, 6 Sep 2024 15:35:32 +0200
Subject: [PATCH] feat(akamai): unzip user content

---
 docs/release-notes.md               |  1 +
 internal/providers/akamai/akamai.go |  9 +++++-
 internal/providers/util/unzip.go    | 43 +++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 internal/providers/util/unzip.go

diff --git a/docs/release-notes.md b/docs/release-notes.md
index c734609fe..6fc298861 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -12,6 +12,7 @@ nav_order: 9
 
 - Support partitioning disk with mounted partitions
 - Support Proxmox VE
+- Support gzipped Akamai user_data
 
 ### Changes
 
diff --git a/internal/providers/akamai/akamai.go b/internal/providers/akamai/akamai.go
index 648be3bee..9b178a8c8 100644
--- a/internal/providers/akamai/akamai.go
+++ b/internal/providers/akamai/akamai.go
@@ -91,7 +91,14 @@ func fetchConfig(f *resource.Fetcher) (types.Config, report.Report, error) {
 		return types.Config{}, report.Report{}, fmt.Errorf("decode base64: %w", err)
 	}
 
-	return util.ParseConfig(f.Logger, data[:n])
+	// The Linode Metadata Service can compress userdata.
+	// We have to gunzip if needed.
+	unzipData, err := util.GunzipIfNeeded(data[:n])
+	if err != nil {
+		return types.Config{}, report.Report{}, fmt.Errorf("unzip: %w", err)
+	}
+
+	return util.ParseConfig(f.Logger, unzipData)
 }
 
 // defaultTokenTTL is the time-to-live (TTL; in seconds) for an authorization
diff --git a/internal/providers/util/unzip.go b/internal/providers/util/unzip.go
new file mode 100644
index 000000000..03455198f
--- /dev/null
+++ b/internal/providers/util/unzip.go
@@ -0,0 +1,43 @@
+// Copyright 2024 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+)
+
+var (
+	gzipMagic = []byte{0x1F, 0x8B, 0x08}
+)
+
+func hasGzipMagicNumber(source []byte) bool {
+	return bytes.HasPrefix(source, gzipMagic)
+}
+
+func GunzipIfNeeded(raw []byte) ([]byte, error) {
+	if !hasGzipMagicNumber(raw) {
+		return raw, nil
+	}
+
+	reader, err := gzip.NewReader(bytes.NewReader(raw))
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+
+	return io.ReadAll(reader)
+}