From ac5576c00cd079a53ba5b30ca8a97934c5019740 Mon Sep 17 00:00:00 2001
From: Theo Satabin <theo.satabin@ign.fr>
Date: Mon, 9 Oct 2023 13:30:12 +0200
Subject: [PATCH 1/2] =?UTF-8?q?Configurabilit=C3=A9=20du=20cache=20de=20le?=
 =?UTF-8?q?cture?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

### [Added]

* `storage` : le cache de lecture est configurable en taille (avec ROK4_READING_LRU_CACHE_SIZE) et en temps de rétention (avec ROK4_READING_LRU_CACHE_TTL)
---
 src/rok4/storage.py | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/rok4/storage.py b/src/rok4/storage.py
index fc7a775..d0b9c70 100644
--- a/src/rok4/storage.py
+++ b/src/rok4/storage.py
@@ -9,6 +9,12 @@
 
 According to functions, all storage types are not necessarily available.
 
+Readings uses a LRU cache system with a TTL. It's possible to configure it with environment variables :
+- ROK4_READING_LRU_CACHE_SIZE : Number of cached element. Default 64. Set 0 or a negative integer to configure a cache without bound. A power of two make cache more efficient.
+- ROK4_READING_LRU_CACHE_TTL : Validity duration of cached element, in seconds. Default 300. 0 or negative integer to disable time validity.
+
+To disable cache, set ROK4_READING_LRU_CACHE_SIZE to 1 and ROK4_READING_LRU_CACHE_TTL to 0.
+
 Using CEPH storage requires environment variables :
 - ROK4_CEPH_CONFFILE
 - ROK4_CEPH_USERNAME
@@ -69,10 +75,33 @@
 __S3_CLIENTS = {}
 __S3_DEFAULT_CLIENT = None
 
+__LRU_SIZE = 64
+__LRU_TTL = 300
+
+try:
+    __LRU_SIZE = int(os.environ["ROK4_READING_LRU_CACHE_SIZE"])
+    if __LRU_SIZE < 1:
+        __LRU_SIZE = None
+except ValueError:
+    pass
+except KeyError:
+    pass
+
+try:
+    __LRU_TTL = int(os.environ["ROK4_READING_LRU_CACHE_TTL"])
+    if __LRU_TTL < 0:
+        __LRU_TTL = 0
+except ValueError:
+    pass
+except KeyError:
+    pass
 
 def __get_ttl_hash():
-    """Return the same value withing 5 minutes time period"""
-    return round(time.time() / 300)
+    """Return the time string rounded according to time-to-live value"""
+    if __LRU_TTL == 0:
+        return time.time()
+    else:
+        return round(time.time() / __LRU_TTL)
 
 
 def __get_s3_client(bucket_name: str) -> Tuple[Dict[str, Union["boto3.client", str]], str, str]:
@@ -294,7 +323,7 @@ def get_data_str(path: str) -> str:
     return get_data_binary(path).decode("utf-8")
 
 
-@lru_cache(maxsize=50)
+@lru_cache(maxsize=__LRU_SIZE)
 def __get_cached_data_binary(path: str, ttl_hash: int, range: Tuple[int, int] = None) -> str:
     """Load data into a binary string, using a LRU cache
 

From 8a5dc1b17ddc2678c4f82464727a900cf9acffe1 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Mon, 9 Oct 2023 12:26:41 +0000
Subject: [PATCH 2/2] =?UTF-8?q?[pre-commit.ci]=20Corrections=20automatique?=
 =?UTF-8?q?s=20appliqu=C3=A9es=20par=20les=20git=20hooks.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/rok4/storage.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/rok4/storage.py b/src/rok4/storage.py
index d0b9c70..a3c6975 100644
--- a/src/rok4/storage.py
+++ b/src/rok4/storage.py
@@ -96,6 +96,7 @@
 except KeyError:
     pass
 
+
 def __get_ttl_hash():
     """Return the time string rounded according to time-to-live value"""
     if __LRU_TTL == 0: