From 6d6202de83160b4eb9702f1a9963d54a40fa4a2a Mon Sep 17 00:00:00 2001
From: Piero Toffanin <pt@masseranolabs.com>
Date: Thu, 16 Nov 2023 15:43:47 -0500
Subject: [PATCH] Add hourly decay limit

---
 .github/workflows/publish-docker.yml | 16 ++++++++++++++++
 libretranslate/app.py                | 27 ++++++++++++++++-----------
 libretranslate/default_values.py     |  5 +++++
 libretranslate/main.py               |  7 +++++++
 4 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/publish-docker.yml b/.github/workflows/publish-docker.yml
index f29254c..8ca45a8 100644
--- a/.github/workflows/publish-docker.yml
+++ b/.github/workflows/publish-docker.yml
@@ -44,6 +44,22 @@ jobs:
         env:
           TAG: ${{ startsWith(github.ref, 'refs/tags/') && steps.get-variables.outputs.version || 'latest' }}
 
+      - name: Free Disk Space (Ubuntu)
+        uses: jlumbroso/free-disk-space@main
+        with:
+          # this might remove tools that are actually needed,
+          # if set to "true" but frees about 6 GB
+          tool-cache: false
+
+          # all of these default to true, but feel free to set to
+          # "false" if necessary for your workflow
+          android: true
+          dotnet: true
+          haskell: true
+          large-packages: true
+          docker-images: true
+          swap-storage: true
+
       - name: Build and push Cuda Image
         uses: docker/build-push-action@v5
         with:
diff --git a/libretranslate/app.py b/libretranslate/app.py
index bad5db1..78994b5 100644
--- a/libretranslate/app.py
+++ b/libretranslate/app.py
@@ -89,7 +89,7 @@ def get_remote_address():
     return ip
 
 
-def get_req_limits(default_limit, api_keys_db, multiplier=1):
+def get_req_limits(default_limit, api_keys_db, db_multiplier=1, multiplier=1):
     req_limit = default_limit
 
     if api_keys_db:
@@ -98,12 +98,13 @@ def get_req_limits(default_limit, api_keys_db, multiplier=1):
         if api_key:
             db_req_limit = api_keys_db.lookup(api_key)
             if db_req_limit is not None:
-                req_limit = db_req_limit * multiplier
+                req_limit = db_req_limit * db_multiplier
 
-    return req_limit
+    return int(req_limit * multiplier)
 
 
-def get_routes_limits(default_req_limit, hourly_req_limit, daily_req_limit, api_keys_db):
+def get_routes_limits(args, api_keys_db):
+    default_req_limit = args.req_limit
     if default_req_limit == -1:
         # TODO: better way?
         default_req_limit = 9999999999999
@@ -111,18 +112,22 @@ def get_routes_limits(default_req_limit, hourly_req_limit, daily_req_limit, api_
     def minute_limits():
         return "%s per minute" % get_req_limits(default_req_limit, api_keys_db)
 
-    def hourly_limits():
-        return "%s per hour" % get_req_limits(hourly_req_limit, api_keys_db, int(os.environ.get("LT_HOURLY_REQ_LIMIT_MULTIPLIER", 60)))
+    def hourly_limits(n):
+        def func():
+          decay = (0.75 ** (n - 1))
+          return "{} per {} hour".format(get_req_limits(args.hourly_req_limit * n, api_keys_db, int(os.environ.get("LT_HOURLY_REQ_LIMIT_MULTIPLIER", 60) * n), decay), n)
+        return func
 
     def daily_limits():
-        return "%s per day" % get_req_limits(daily_req_limit, api_keys_db, int(os.environ.get("LT_DAILY_REQ_LIMIT_MULTIPLIER", 1440)))
+        return "%s per day" % get_req_limits(args.daily_req_limit, api_keys_db, int(os.environ.get("LT_DAILY_REQ_LIMIT_MULTIPLIER", 1440)))
 
     res = [minute_limits]
 
-    if hourly_req_limit > 0:
-      res.append(hourly_limits)
+    if args.hourly_req_limit > 0:
+      for n in range(1, args.hourly_req_limit_decay + 2):
+        res.append(hourly_limits(n))
 
-    if daily_req_limit > 0:
+    if args.daily_req_limit > 0:
         res.append(daily_limits)
 
     return res
@@ -202,7 +207,7 @@ def create_app(args):
         limiter = Limiter(
             key_func=get_remote_address,
             default_limits=get_routes_limits(
-                args.req_limit, args.hourly_req_limit, args.daily_req_limit, api_keys_db
+                args, api_keys_db
             ),
             storage_uri=args.req_limit_storage,
             default_limits_deduct_when=lambda req: True, # Force cost to be called after the request
diff --git a/libretranslate/default_values.py b/libretranslate/default_values.py
index 2f44bba..96a833e 100644
--- a/libretranslate/default_values.py
+++ b/libretranslate/default_values.py
@@ -66,6 +66,11 @@ _default_options_objects = [
         'default_value': -1,
         'value_type': 'int'
     },
+    {
+        'name': 'HOURLY_REQ_LIMIT_DECAY',
+        'default_value': 0,
+        'value_type': 'int'
+    },
     {
         'name': 'DAILY_REQ_LIMIT',
         'default_value': -1,
diff --git a/libretranslate/main.py b/libretranslate/main.py
index 8865379..581e4f5 100644
--- a/libretranslate/main.py
+++ b/libretranslate/main.py
@@ -42,6 +42,13 @@ def get_args():
         metavar="<number>",
         help="Set the default maximum number of requests per hour per client, in addition to req-limit. (%(default)s)",
     )
+    parser.add_argument(
+        "--hourly-req-limit-decay",
+        default=DEFARGS['HOURLY_REQ_LIMIT_DECAY'],
+        type=int,
+        metavar="<number>",
+        help="When used in combination with hourly-req-limit, adds additional hourly restrictions that logaritmically decrease for each additional hour. (%(default)s)",
+    )
     parser.add_argument(
         "--daily-req-limit",
         default=DEFARGS['DAILY_REQ_LIMIT'],