Merge pull request 'Use the AWS PHP SDK's default credential provider chain' (#2) from wn/ttrss-cache-s3:feature/use-default-cred-provider-chain into master

Reviewed-on: https://dev.tt-rss.org/tt-rss/ttrss-cache-s3/pulls/2

2 files changed, 18 insertions, 7 deletions

diff --git a/README.md b/README.md
index 2a1a54d..78e4e40 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Cache S3
 
-File cache backend using S3 protocol (e.g. Minio)
+File cache backend using S3 protocol (e.g. Minio, AWS S3).
 
 ## Installation
 
@@ -14,6 +14,12 @@ The following options are required:
 TTRSS_CACHE_S3_ENDPOINT=http://example.com:9000
 TTRSS_CACHE_S3_BUCKET=bucket-name
 TTRSS_CACHE_S3_REGION=us-east-1
+```
+
+The following options are required if you're directly providing access keys (i.e. not using an IAM role or alternative approach).
+See [Credentials for the AWS SDK for PHP Version 3](https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/guide_credentials.html) for more information.
+
+```ini
 TTRSS_CACHE_S3_ACCESS_KEY=xxx
 TTRSS_CACHE_S3_SECRET_KEY=yyy
 ```
diff --git a/init.php b/init.php
index 10946c9..d8b42ab 100644
--- a/init.php
+++ b/init.php
@@ -34,17 +34,22 @@ class Cache_S3 extends Plugin implements Cache_Adapter {
 		Config::add(self::CACHE_S3_ACCESS_KEY, "", Config::T_STRING);
 		Config::add(self::CACHE_S3_SECRET_KEY, "", Config::T_STRING);
 
-		/** @phpstan-ignore-next-line */
-		$this->s3 = new Aws\S3\S3Client([
+		$s3_client_props = [
 			'version' => 'latest',
 			'region'  => Config::get(self::CACHE_S3_REGION),
 			'endpoint' => Config::get(self::CACHE_S3_ENDPOINT),
 			'use_path_style_endpoint' => true,
-			'credentials' => [
+		];
+
+		if (Config::get(self::CACHE_S3_ACCESS_KEY) && Config::get(self::CACHE_S3_SECRET_KEY)) {
+			$s3_client_props['credentials'] = [
 			  'key'    => Config::get(self::CACHE_S3_ACCESS_KEY),
-			  'secret' => Config::get(self::CACHE_S3_SECRET_KEY)
-			],
-		]);
+			  'secret' => Config::get(self::CACHE_S3_SECRET_KEY),
+			];
+		}
+
+		/** @phpstan-ignore-next-line */
+		$this->s3 = new Aws\S3\S3Client($s3_client_props);
 
 		/** @phpstan-ignore-next-line */
 		$this->s3->registerStreamWrapper();