Merge pull request #58 from NASA-IMPACT/feature/57-cache

Feature/57 cache

covid_api/api/api_v1/endpoints/datasets.py

@@ -1,11 +1,11 @@
 """Dataset endpoints."""
-
 from covid_api.db.static.errors import InvalidIdentifier
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter, HTTPException, Depends, Response
 
 from covid_api.models.static import Datasets
 from covid_api.db.static.datasets import datasets
-
+from covid_api.db.memcache import CacheLayer
+from covid_api.api import utils
 
 router = APIRouter()
 
@@ -15,9 +15,25 @@
     responses={200: dict(description="return a list of all available datasets")},
     response_model=Datasets,
 )
-def get_datasets():
+def get_datasets(
+    response: Response, cache_client: CacheLayer = Depends(utils.get_cache),
+):
     """Return a list of datasets."""
-    return datasets.get_all()
+    dataset_hash = utils.get_hash(spotlight_id="all")
+    content = None
+
+    if cache_client:
+        try:
+            content = cache_client.get_image_from_cache(dataset_hash)
+            response.headers["X-Cache"] = "HIT"
+        except Exception:
+            content = None
+    if not content:
+        content = datasets.get_all()
+        if cache_client and content:
+            cache_client.set_dataset_cache(dataset_hash, content)
+
+    return content
 
 
 @router.get(
@@ -27,10 +43,28 @@ def get_datasets():
     },
     response_model=Datasets,
 )
-def get_dataset(spotlight_id: str):
+def get_dataset(
+    spotlight_id: str,
+    response: Response,
+    cache_client: CacheLayer = Depends(utils.get_cache),
+):
     """Return dataset info for all datasets available for a given spotlight"""
     try:
-        return datasets.get(spotlight_id)
+        dataset_hash = utils.get_hash(spotlight_id=spotlight_id)
+        content = None
+
+        if cache_client:
+            try:
+                content = cache_client.get_image_from_cache(dataset_hash)
+                response.headers["X-Cache"] = "HIT"
+            except Exception:
+                content = None
+        if not content:
+            content = datasets.get(spotlight_id)
+            if cache_client and content:
+                cache_client.set_dataset_cache(dataset_hash, content)
+
+        return content
     except InvalidIdentifier:
         raise HTTPException(
             status_code=404, detail=f"Invalid spotlight identifier: {spotlight_id}"

covid_api/api/utils.py

@@ -44,7 +44,7 @@ def get_cache(request: Request) -> CacheLayer:
 
 
 def get_hash(**kwargs: Any) -> str:
-    """Create hash from a dict."""
+    """Create hash from kwargs."""
     return hashlib.sha224(json.dumps(kwargs, sort_keys=True).encode()).hexdigest()
 
 

covid_api/db/memcache.py

@@ -1,6 +1,6 @@
 """covid_api.cache.memcache: memcached layer."""
 
-from typing import Optional, Tuple
+from typing import Optional, Tuple, Dict
 
 from bmemcached import Client
 
@@ -61,3 +61,14 @@ def set_image_cache(
             return self.client.set(img_hash, body, time=timeout)
         except Exception:
             return False
+
+    def get_dataset_from_cache(self, ds_hash: str) -> Dict:
+        """Get dataset response from cache layer"""
+        return self.client.get(ds_hash)
+
+    def set_dataset_cache(self, ds_hash: str, body: Dict, timeout: int = 3600) -> bool:
+        """Set dataset response in cache layer"""
+        try:
+            return self.client.set(ds_hash, body, time=timeout)
+        except Exception:
+            return False