Add live endpoint to admin server

* refactor io tests
* add network package to windows

CHANGELOG.md

@@ -9,7 +9,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
  - #1933, #2109, Add a minimal health check endpoint - @steve-chavez
    + For enabling this, the `admin-server-port` config must be set explictly
-   + The check is at the `<host>:<admin_server_port>/ready` endpoint
+   + The check is at the `<host>:<admin_server_port>/live` endpoint. A 200 OK status will be returned if postgrest is alive, otherwise a 503 will be returned.
+   + A `<host>:<admin_server_port>/ready` endpoint is available for checking a correct internal state(the database connection plus the schema cache). 200 OK = ready, 503 = not ready.
 
 ### Fixed
 

postgrest.cabal

@@ -97,6 +97,7 @@ library
                     , lens                      >= 4.14 && < 5.1
                     , lens-aeson                >= 1.0.1 && < 1.2
                     , mtl                       >= 2.2.2 && < 2.3
+                    , network                   >= 2.6 && < 3.2
                     , network-uri               >= 2.6.1 && < 2.8
                     , optparse-applicative      >= 0.13 && < 0.17
                     , parsec                    >= 3.1.11 && < 3.2
@@ -134,7 +135,6 @@ library
     build-depends:
       unix
       , directory >= 1.2.6 && < 1.4
-      , network   >= 2.6 && < 3.2
     exposed-modules:
       PostgREST.Unix
 

src/PostgREST/Admin.hs

@@ -31,7 +31,10 @@ postgrestAdmin appState appConfig req respond  = do
       else do
         result <- SQL.use (AppState.getPool appState) $ SQL.sql "SELECT 1"
         respond $ Wai.responseLBS (if isRight result && isMainAppReachable then HTTP.status200 else HTTP.status503) [] mempty
-    _ -> respond $ Wai.responseLBS HTTP.status404 [] mempty
+    ["live"] ->
+      respond $ Wai.responseLBS (if isMainAppReachable then HTTP.status200 else HTTP.status503) [] mempty
+    _ ->
+      respond $ Wai.responseLBS HTTP.status404 [] mempty
 
 -- Try to connect to the main app socket
 -- Note that it doesn't even send a valid HTTP request, we just want to check that the main app is accepting connections

test/io-tests/test_io.py

@@ -778,15 +778,26 @@ def test_admin_not_found(defaultenv):
 def test_admin_ready_dependent_on_main_app(defaultenv):
     "Should get a failure from the admin ready endpoint if the main app also fails"
 
-    env = {
-        **defaultenv,
-        "PGRST_ADMIN_SERVER_PORT": "3001",
-    }
-
-    with run(env=env, port=None) as postgrest:
+    with run(env=defaultenv, adminport=freeport()) as postgrest:
         # delete the unix socket to make the main app fail
-        os.remove(env["PGRST_SERVER_UNIX_SOCKET"])
-        response = requests.get(
-            f"http://localhost:{env['PGRST_ADMIN_SERVER_PORT']}/ready"
-        )
+        os.remove(defaultenv["PGRST_SERVER_UNIX_SOCKET"])
+        response = postgrest.admin.get("/ready")
+        assert response.status_code == 503
+
+
+def test_admin_live_good(defaultenv):
+    "Should get a success from the admin live endpoint if the main app is running"
+
+    with run(env=defaultenv, port=freeport(), adminport=freeport()) as postgrest:
+        response = postgrest.admin.get("/live")
+        assert response.status_code == 200
+
+
+def test_admin_live_dependent_on_main_app(defaultenv):
+    "Should get a failure from the admin live endpoint if the main app also fails"
+
+    with run(env=defaultenv, adminport=freeport()) as postgrest:
+        # delete the unix socket to make the main app fail
+        os.remove(defaultenv["PGRST_SERVER_UNIX_SOCKET"])
+        response = postgrest.admin.get("/live")
         assert response.status_code == 503