Update/cleanup; added Queue class in server for better "instancing"; …

…restructured files for Dockerfile

client/rq_client.py

@@ -0,0 +1,60 @@
+import requests
+from rich import print
+
+
+class RestQueue:
+    def __init__(self, host: str, port: int, queue_name: str):
+        self._host = host
+        self._port = port
+        self._queue_name = queue_name
+        self._queue_url = f"http://{host}:{port}/queues/{queue_name}"
+        self._session = requests.Session()
+
+    def create(self):
+        response = self._session.post(self._queue_url)
+        return response.status_code, response.json()
+
+    def push(self, value):
+        if value is None:
+            print(f"pushed value cannot be None")
+            return
+
+        url = f"{self._queue_url}/push"
+        response = self._session.post(url, params={"value": value})
+        if response.status_code == 404:
+            print(f"no such queue {self._queue_name!r}")
+
+        return response.json()
+
+    def pop(self):
+        url = f"{self._queue_url}/pop"
+        response = self._session.post(url)
+        if response.status_code == 404:
+            print(f"no such queue {self._queue_name!r}")
+            return
+
+        return response.json()
+
+    def list(self):
+        url = self._queue_url
+        response = self._session.get(url)
+        if response.status_code == 404:
+            print(f"no such queue {self._queue_name!r}")
+            return
+
+        return response.json()
+
+
+if __name__ == '__main__':
+    qname = "test"
+    rq = RestQueue("localhost", 8000, qname)
+    print(rq.create())
+
+    print(rq.push(100))
+    print(rq.push("secret message"))
+    print(rq.push(3.14159))
+    print(rq.push(True))
+
+    print(rq.list())
+
+    print(rq.pop())

docker/Dockerfile

@@ -2,10 +2,8 @@ FROM python:3.9.2-alpine
 
 WORKDIR /usr/src/app
 
-COPY src .
+COPY ../rest_queue/src .
 
 RUN pip install --no-cache-dir -r requirements.txt
 
 CMD [ "uvicorn", "--host", "0.0.0.0", "rest_queue:app" ]
-
-

rest_queue/src/rest_queue.py

@@ -1,21 +1,59 @@
 #
-# simple_rest_queue.py
+# rest_queue.py
 #
-# A simple FastAPI web service that maintains multiple named FIFO queues
+# A lightweight FastAPI web service that maintains multiple named FIFO queues
 # that can be created, pushed, and popped using REST calls
 #
+# NOTE: this queue does NO persistence, so restarting the server will lose all
+# items that are still in the queue.
+#
 from collections import deque
 from typing import Dict
 
 import fastapi
 
+
+class Queue:
+    """
+    A small container class to wrap a deque with push and pop methods,
+    and __iter__ and __len__ dunder methods.
+    """
+    def __init__(self, name):
+        self._name = name
+        self._contents = deque()
+
+    def __iter__(self):
+        return iter(self._contents)
+
+    def __len__(self):
+        return len(self._contents)
+
+    def push(self, value):
+        self._contents.append(value)
+
+    def pop(self):
+        return self._contents.popleft()
+
+
 # registry for REST-accessible queues
-queues: Dict[str, deque] = {}
+queues: Dict[str, Queue] = {}
 
 
 app = fastapi.FastAPI()
 
+"""
+Implement these endpoints:
 
+Create  - POST    http://host:port/queues/<queue_name>
+Push    - POST    http://host:port/queues/<queue_name>/push
+Pop     - POST    http://host:port/queues/<queue_name>/pop
+List    - GET     http://host:port/queues/<queue_name>
+Delete  - DELETE  http://host:port/queues/<queue_name>
+List    - GET     http://host:port/queues
+"""
+
+
+# find HTTP statuses at http://httpstatuses.com
 @app.post("/queues/{queue_name}", status_code=fastapi.status.HTTP_201_CREATED)
 async def queue_new(queue_name: str):
     """
@@ -28,12 +66,30 @@ async def queue_new(queue_name: str):
                                     detail=f"Queue {queue_name!r} already exists")
 
     # create new deque and add to registry under the given name
-    queues[queue_name] = deque()
+    queues[queue_name] = Queue(queue_name)
 
     return {"message": f"created {queue_name!r}"}
 
 
-@app.get("/queues/{queue_name}", status_code=fastapi.status.HTTP_200_OK)
+@app.post("/queues/{queue_name}/push")
+async def queue_push(queue_name: str, value: str):
+    """
+    Push new value onto queue.
+    """
+    if queue_name not in queues:
+        raise fastapi.HTTPException(status_code=fastapi.status.HTTP_404_NOT_FOUND,
+                                    detail=f"No such queue {queue_name!r}")
+
+    q = queues[queue_name]
+    q.push(value)
+
+    return {
+        "message": f"push to queue {queue_name!r}",
+        "remaining_queue_size": len(q),
+    }
+
+
+@app.post("/queues/{queue_name}/pop")
 async def queue_pop(queue_name: str):
     """
     Pop oldest value from queue, or None if queue is empty.
@@ -44,35 +100,34 @@ async def queue_pop(queue_name: str):
 
     q = queues[queue_name]
     if q:
-        value = q.popleft()
+        value = q.pop()
     else:
         value = None
 
-    return {"message": f"get from queue {queue_name!r}",
+    return {"message": f"pop from queue {queue_name!r}",
             "data": value,
             "remaining_queue_size": len(q),
             }
 
 
-@app.put("/queues/{queue_name}", status_code=fastapi.status.HTTP_200_OK)
-async def queue_push(queue_name: str, value: str):
+@app.get("/queues/{queue_name}")
+async def queue_list(queue_name: str):
     """
-    Push new value onto queue.
+    List out contents of queue.
     """
     if queue_name not in queues:
         raise fastapi.HTTPException(status_code=fastapi.status.HTTP_404_NOT_FOUND,
                                     detail=f"No such queue {queue_name!r}")
 
     q = queues[queue_name]
-    q.append(value)
 
     return {
-        "message": f"put to queue {queue_name!r}",
-        "remaining_queue_size": len(q),
+        "message": f"items in queue {queue_name!r}",
+        "items": list(q),
     }
 
 
-@app.delete("/queues/{queue_name}", status_code=fastapi.status.HTTP_200_OK)
+@app.delete("/queues/{queue_name}")
 async def queue_delete(queue_name: str,
                        safe_delete: bool = True):
     """
@@ -86,7 +141,10 @@ async def queue_delete(queue_name: str,
 
     if safe_delete and q:
         raise fastapi.HTTPException(status_code=fastapi.status.HTTP_409_CONFLICT,
-                                    detail=f"Queue {queue_name!r} not empty (contains {len(q)} items)")
+                                    detail={"message": f"Queue {queue_name!r} not empty",
+                                            "count": len(q),
+                                            }
+                                    )
 
     # remove queue from registry
     del queues[queue_name]
@@ -97,24 +155,7 @@ async def queue_delete(queue_name: str,
     }
 
 
-@app.get("/queues/{queue_name}/list", status_code=fastapi.status.HTTP_200_OK)
-async def queue_list(queue_name: str):
-    """
-    List out contents of queue.
-    """
-    if queue_name not in queues:
-        raise fastapi.HTTPException(status_code=fastapi.status.HTTP_404_NOT_FOUND,
-                                    detail=f"No such queue {queue_name!r}")
-
-    q = queues[queue_name]
-
-    return {
-        "message": f"items in queue {queue_name!r}",
-        "items": list(q),
-    }
-
-
-@app.get("/queues", status_code=fastapi.status.HTTP_200_OK)
+@app.get("/queues")
 async def queue_list_all():
     """
     List out all queue names.