From 84fcbdbafdf58d0f1963c69bad5b6bcb9c805ce1 Mon Sep 17 00:00:00 2001
From: Frederick Muriuki Muriithi
Date: Thu, 3 Mar 2022 10:10:12 +0300
Subject: Add endpoint for checking state of external processes

Long-running computations are handed off to external processes. This avoids
timeouts in the webserver, and also reduces chances of instability of the
webserver.

The results of these long-running computations are needed eventually, so this
commit provides a way to check for the state of the computation, and the
results if any.
---
 gn3/api/async_commands.py | 21 +++++++++++++++++++++
 gn3/app.py                |  2 ++
 2 files changed, 23 insertions(+)
 create mode 100644 gn3/api/async_commands.py

diff --git a/gn3/api/async_commands.py b/gn3/api/async_commands.py
new file mode 100644
index 0000000..f8400c8
--- /dev/null
+++ b/gn3/api/async_commands.py
@@ -0,0 +1,21 @@
+"""Endpoints and functions concerning commands run in external processes."""
+import json
+
+import redis
+from flask import jsonify, Blueprint
+
+async_commands = Blueprint("async_commands", __name__)
+
+@async_commands.route("/state/<command_id>")
+def command_state(command_id):
+    with redis.Redis() as rconn:
+        state = rconn.hgetall(name=command_id)
+        if not state:
+            return jsonify(
+                status=404,
+                error="The command id provided does not exist.")
+        state = {
+            key.decode("utf-8"): val.decode("utf8")
+            for key,val in state.items()
+        }
+        return jsonify(state)
diff --git a/gn3/app.py b/gn3/app.py
index a1a3795..790e87c 100644
--- a/gn3/app.py
+++ b/gn3/app.py
@@ -15,6 +15,7 @@ from gn3.api.correlation import correlation
 from gn3.api.data_entry import data_entry
 from gn3.api.wgcna import wgcna
 from gn3.api.ctl import ctl
+from gn3.api.async_commands import async_commands
 
 def create_app(config: Union[Dict, str, None] = None) -> Flask:
     """Create a new flask object"""
@@ -47,4 +48,5 @@ def create_app(config: Union[Dict, str, None] = None) -> Flask:
     app.register_blueprint(data_entry, url_prefix="/api/dataentry")
     app.register_blueprint(wgcna, url_prefix="/api/wgcna")
     app.register_blueprint(ctl, url_prefix="/api/ctl")
+    app.register_blueprint(async_commands, url_prefix="/api/async_commands")
     return app
-- 
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