Add Hook Events for Chains and Safe Apps (#964)

- Refactors the WebHook hook logic for the Safe Client Gateway client.
- A WebHook event is now represented as a `@dataclass` – `HookEvent`. This `HookEvent` can have two types:
  * `CHAIN_UPDATE` – represents chain related updates (more specifically updates to `Chain`, `GasPrice`, `Feature` – chain feature, and `Wallet`).
  * `SAFE_APPS_UPDATE` – represents safe app related updates (more specifically updates to `SafeApp`, `Provider`, `Tag` and `Feature` – safe app feature).
- The new web hooks are under a feature preview and can be enabled by setting the environment variable `FF_HOOK_EVENTS` to `true`.
  * If `FF_HOOK_EVENTS` is set to `false`, the `/v2/flush` endpoint is triggered (as before).

src/chains/signals.py

@@ -2,47 +2,91 @@
 from typing import Any
 
 from django.conf import settings
-from django.db.models.signals import post_delete, post_save
+from django.db.models.signals import m2m_changed, post_delete, post_save, pre_delete
 from django.dispatch import receiver
 
-import clients.safe_client_gateway
+from clients.safe_client_gateway import HookEvent, flush, hook_event
 
 from .models import Chain, Feature, GasPrice, Wallet
 
 logger = logging.getLogger(__name__)
 
 
-def _flush_cgw_chains() -> None:
-    clients.safe_client_gateway.flush(
-        cgw_url=settings.CGW_URL,
-        cgw_flush_token=settings.CGW_FLUSH_TOKEN,
-        json={"invalidate": "Chains"},
-    )
-
-
 @receiver(post_save, sender=Chain)
 @receiver(post_delete, sender=Chain)
-def on_chain_update(sender: Chain, **kwargs: Any) -> None:
+def on_chain_update(sender: Chain, instance: Chain, **kwargs: Any) -> None:
     logger.info("Chain update. Triggering CGW webhook")
-    _flush_cgw_chains()
+    if settings.FF_HOOK_EVENTS:
+        hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.id))
+    else:
+        flush()
 
 
 @receiver(post_save, sender=GasPrice)
 @receiver(post_delete, sender=GasPrice)
-def on_gas_price_update(sender: GasPrice, **kwargs: Any) -> None:
+def on_gas_price_update(sender: GasPrice, instance: GasPrice, **kwargs: Any) -> None:
     logger.info("GasPrice update. Triggering CGW webhook")
-    _flush_cgw_chains()
+    if settings.FF_HOOK_EVENTS:
+        hook_event(
+            HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.chain.id)
+        )
+    else:
+        flush()
 
 
+# pre_delete is used because on pre_delete the model still has chains
+# which is not the case on post_delete
 @receiver(post_save, sender=Feature)
-@receiver(post_delete, sender=Feature)
-def on_feature_update(sender: Feature, **kwargs: Any) -> None:
+@receiver(pre_delete, sender=Feature)
+def on_feature_changed(sender: Feature, instance: Feature, **kwargs: Any) -> None:
     logger.info("Feature update. Triggering CGW webhook")
-    _flush_cgw_chains()
+    if settings.FF_HOOK_EVENTS:
+        # A Feature change affects all the chains that have this feature
+        for chain in instance.chains.all():
+            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
+    else:
+        flush()
+
 
+@receiver(m2m_changed, sender=Feature.chains.through)
+def on_feature_chains_changed(
+    sender: Feature, instance: Feature, action: str, pk_set: set[int], **kwargs: Any
+) -> None:
+    logger.info("FeatureChains update. Triggering CGW webhook")
+    if action == "post_add" or action == "post_remove":
+        if settings.FF_HOOK_EVENTS:
+            for chain_id in pk_set:
+                hook_event(
+                    HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id)
+                )
+        else:
+            flush()
 
+
+# pre_delete is used because on pre_delete the model still has chains
+# which is not the case on post_delete
 @receiver(post_save, sender=Wallet)
-@receiver(post_delete, sender=Wallet)
-def on_wallet_update(sender: Wallet, **kwargs: Any) -> None:
+@receiver(pre_delete, sender=Wallet)
+def on_wallet_changed(sender: Wallet, instance: Wallet, **kwargs: Any) -> None:
     logger.info("Wallet update. Triggering CGW webhook")
-    _flush_cgw_chains()
+    if settings.FF_HOOK_EVENTS:
+        # A Wallet change affects all the chains that have this wallet
+        for chain in instance.chains.all():
+            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
+    else:
+        flush()
+
+
+@receiver(m2m_changed, sender=Wallet.chains.through)
+def on_wallet_chains_changed(
+    sender: Wallet, instance: Wallet, action: str, pk_set: set[int], **kwargs: Any
+) -> None:
+    logger.info("WalletChains update. Triggering CGW webhook")
+    if action == "post_add" or action == "post_remove":
+        if settings.FF_HOOK_EVENTS:
+            for chain_id in pk_set:
+                hook_event(
+                    HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id)
+                )
+        else:
+            flush()

src/chains/tests/test_signals.py

@@ -1,11 +1,12 @@
 import responses
 from django.test import TestCase, override_settings
 
-from chains.models import Feature, Wallet
-from chains.tests.factories import ChainFactory, GasPriceFactory
+from ..models import Feature, Wallet
+from ..tests.factories import ChainFactory, GasPriceFactory
 
 
 @override_settings(
+    FF_HOOK_EVENTS=False,
     CGW_URL="http://127.0.0.1",
     CGW_FLUSH_TOKEN="example-token",
 )
@@ -113,6 +114,7 @@ def test_on_chain_update_with_no_flush_token_set(self) -> None:
 
 
 @override_settings(
+    FF_HOOK_EVENTS=False,
     CGW_URL="http://127.0.0.1",
     CGW_FLUSH_TOKEN="example-token",
 )
@@ -165,6 +167,7 @@ def test_on_feature_update_hook_call(self) -> None:
 
 
 @override_settings(
+    FF_HOOK_EVENTS=False,
     CGW_URL="http://127.0.0.1",
     CGW_FLUSH_TOKEN="example-token",
 )
@@ -217,6 +220,7 @@ def test_on_wallet_update_hook_call(self) -> None:
 
 
 @override_settings(
+    FF_HOOK_EVENTS=False,
     CGW_URL="http://127.0.0.1",
     CGW_FLUSH_TOKEN="example-token",
 )