OCT-1867: Add a rewards rate value for the server

backend/app/infrastructure/routes/epochs.py

@@ -3,7 +3,10 @@
 
 from app.extensions import api, epochs
 from app.infrastructure import OctantResource, graphql
-from app.modules.octant_rewards.controller import get_octant_rewards
+from app.modules.octant_rewards.controller import (
+    get_octant_rewards,
+    get_epoch_rewards_rate,
+)
 
 ns = Namespace("epochs", description="Octant epochs")
 api.add_namespace(ns)
@@ -113,6 +116,15 @@ def get(self):
     },
 )
 
+epoch_rewards_rate_model = api.model(
+    "EpochRewardsRate",
+    {
+        "rewardsRate": fields.Float(
+            required=True, description="Rewards rate for the given epoch."
+        )
+    },
+)
+
 
 @ns.route("/info/<int:epoch>")
 @ns.doc(
@@ -131,3 +143,18 @@ def get(self, epoch: int):
         app.logger.debug(f"Got: {stats}")
 
         return stats.to_dict()
+
+
+@ns.route("/rewards-rate/<int:epoch>")
+@ns.doc(
+    description="Returns a rewards rate for given epoch. Returns data for all states of epochs.",
+    params={
+        "epoch": "Epoch number",
+    },
+)
+class EpochRewardsRate(OctantResource):
+    @ns.marshal_with(epoch_rewards_rate_model)
+    @ns.response(200, "Epoch's rewards rate successfully retrieved.")
+    def get(self, epoch: int):
+        app.logger.debug(f"Getting rewards rate for epoch {epoch}")
+        return {"rewardsRate": get_epoch_rewards_rate(epoch)}

backend/app/modules/octant_rewards/controller.py

@@ -3,6 +3,7 @@
 from app.exceptions import NotImplementedForGivenEpochState
 from app.modules.dto import OctantRewardsDTO
 from app.modules.registry import get_services
+from app.modules.octant_rewards import core
 
 
 def get_octant_rewards(epoch_num: int) -> OctantRewardsDTO:
@@ -24,3 +25,8 @@ def get_last_finalized_epoch_leverage() -> float:
     service = get_services(context.epoch_state).octant_rewards_service
 
     return service.get_leverage(context)
+
+
+def get_epoch_rewards_rate(epoch_num: int) -> float:
+    context = epoch_context(epoch_num)
+    return core.get_rewards_rate(context.epoch_details.epoch_num)

backend/app/modules/octant_rewards/core.py

@@ -7,6 +7,7 @@
 from app.engine.octant_rewards.operational_cost import OperationalCostPayload
 from app.engine.octant_rewards.ppf import PPFPayload
 from app.engine.octant_rewards.total_and_individual import TotalAndAllIndividualPayload
+from app.modules.staking.proceeds.core import ESTIMATED_STAKING_REWARDS_RATE
 
 
 @dataclass
@@ -66,3 +67,11 @@ def calculate_rewards(
         ppf_value=ppf_value,
         community_fund=cf_value,
     )
+
+
+def get_rewards_rate(_: int) -> float:
+    """
+    Returns the rewards rate for the given epoch.
+    """
+    # TODO Staking Rewards Rate is a static value for now but it may be calculated dynamically in the future: https://linear.app/golemfoundation/issue/OCT-1916/make-apr-a-dynamically-computed-one
+    return ESTIMATED_STAKING_REWARDS_RATE

backend/app/modules/staking/proceeds/core.py

@@ -8,17 +8,17 @@
 ESTIMATED_STAKED_AMOUNT = 100000_000000000_000000000
 
 # TODO call an API to get a real value instead of hardcoding: https://linear.app/golemfoundation/issue/OCT-902/api-call-to-get-validators-api
-ESTIMATED_STAKING_APR = 0.038
+ESTIMATED_STAKING_REWARDS_RATE = 0.038
 
 
 def estimate_staking_proceeds(
     epoch_duration_sec: int,
     staked_amount=ESTIMATED_STAKED_AMOUNT,
-    apr=ESTIMATED_STAKING_APR,
+    staking_rewards=ESTIMATED_STAKING_REWARDS_RATE,
 ) -> int:
     if epoch_duration_sec <= 0:
         return 0
-    return int(int(staked_amount * apr) / 31536000 * epoch_duration_sec)
+    return int(int(staked_amount * staking_rewards) / 31536000 * epoch_duration_sec)
 
 
 def sum_mev(

backend/tests/modules/octant_rewards/test_apr_core.py

@@ -0,0 +1,17 @@
+import pytest
+
+from app.modules.octant_rewards.core import get_rewards_rate
+from app.modules.staking.proceeds.core import ESTIMATED_STAKING_REWARDS_RATE
+
+
+@pytest.fixture(autouse=True)
+def before(app):
+    pass
+
+
+@pytest.mark.parametrize("epoch_num", [1, 2, 3, 4, 5])
+def test_get_epoch_rewards_rate_return_valid_value(epoch_num: int):
+    actual_result = get_rewards_rate(epoch_num)
+    expected_result = ESTIMATED_STAKING_REWARDS_RATE
+
+    assert actual_result == expected_result