[#173] s3: Support variable key length

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

scenarios/libs/keygen.js

@@ -12,6 +12,23 @@ export function generateS3Key() {
     }
   }
 
-    key += (__ENV.OBJ_NAME || uuidv4());
+  key += objName();
   return key;
 }
+
+const asciiLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
+
+function objName() {
+  if (__ENV.OBJ_NAME) {
+    return __ENV.OBJ_NAME;
+  }
+  const length = parseInt(__ENV.OBJ_NAME_LENGTH || '0');
+  if (length > 0) {
+    let name = "";
+    for (let i = 0; i < length; i++) {
+      name += asciiLetters.charAt(Math.floor(Math.random() * asciiLetters.length));
+    }
+    return name;
+  }
+  return uuidv4();
+}

scenarios/run_scenarios.md

@@ -138,6 +138,7 @@ Options (in addition to the common options):
   * `DELETE_AGE` - age of object in seconds before which it can not be deleted. This parameter can be used to control how many objects we have in the system under load.
   * `SLEEP_DELETE` - time interval (in seconds) between deleting VU iterations.
   * `OBJ_NAME` - if specified, this name will be used for all write operations instead of random generation.
+  * `OBJ_NAME_LENGTH` - if specified, then name of the object will be generated with the specified length of ASCII characters.
   * `DIR_HEIGHT`, `DIR_WIDTH` - if both specified, object name will consist of `DIR_HEIGHT` directories, each of which can have `DIR_WIDTH` subdirectories, for example for `DIR_HEIGHT = 3, DIR_WIDTH = 100`, object names will be `/dir{1...100}/dir{1...100}/dir{1...100}/{uuid || OBJ_NAME}`
 
 ## S3 Multipart