Add metricsAction: supervised loop sampling ekg store to rrd via rrdtool

test/MetricsSpec.hs

@@ -14,9 +14,19 @@ import HomeAssistant.Runtime.Metrics
   , buildSchema
   , buildCreateArgs
   , buildUpdateArgs
+  , ensureRrd
+  , sampleAndUpdate
+  , metricsAction
   )
 import qualified System.Metrics as M (Value (..))
 import Test.Hspec
+import Control.Exception (try, SomeException)
+import System.Directory (findExecutable, getTemporaryDirectory, removeFile)
+import System.Exit (ExitCode (ExitSuccess))
+import System.Process (readProcessWithExitCode)
+import qualified System.Metrics as Metrics
+import qualified System.Metrics.Counter as Counter
+import qualified System.Metrics.Gauge as Gauge
 
 spec :: Spec
 spec = do
@@ -96,3 +106,26 @@ spec = do
           , "ds1"
           , "N:U"
           ]
+
+  describe "end-to-end (rrdtool-gated)" $ do
+    it "creates an rrd, samples, and updates it" $ do
+      mRrdtool <- findExecutable "rrdtool"
+      case mRrdtool of
+        Nothing -> pendingWith "rrdtool not on PATH"
+        Just rrdtool -> do
+          store <- Metrics.newStore
+          c <- Metrics.createCounter "test.counter" store
+          g <- Metrics.createGauge "test.gauge" store
+          Counter.inc c
+          Gauge.set g 42
+          tmp <- getTemporaryDirectory
+          let rrdPath = tmp ++ "/hass-controller-metrics-test.rrd"
+          _ <- try (removeFile rrdPath) :: IO (Either SomeException ())
+          schema <- buildSchema <$> Metrics.sampleAll store
+          ensureRrd rrdtool rrdPath schema
+          sampleAndUpdate store rrdtool rrdPath schema
+          (rc, out, _) <- readProcessWithExitCode rrdtool ["fetch", rrdPath, "AVERAGE"] ""
+          rc `shouldBe` ExitSuccess
+          length out `shouldSatisfy` (> 0)
+          _ <- try (removeFile rrdPath) :: IO (Either SomeException ())
+          return ()