Consider use of http-streams

[istathar]

I like http-streams, because I wrote it! and because I like the io-streams library's approach to the Streaming I/O problem.

It was, however, the first Haskell library I wrote, and, though not unmaintained I have hardly touched it in years. It works fine, as evidenced by the large amount of traffic that is driven using it at a number of companies.

But there's no one who is really looking after it, and I'm a bit worried about some of the things in its dependency stack in turn bitrotting.

Inside this open source project it is used by core-telemetry as the HTTP client library which connects to Honeycomb and sends events. We could consider replacing it with http-client (which would be ironic, seeing as how I first wrote http-streams because I didn't like the semantics of Snoyman's Conduit based client) as it is the defacto standard implementation in Haskell and more likely to be better tested around narly edge cases.

Or, we could invest in ensuring http-streams is up to date and possibly bring it under the umbrella of this project.

Thoughts?

[istathar]

The relevant code in core-telemetry is

unbeliever/core-telemetry/lib/Core/Telemetry/Honeycomb.hs

Lines 216 to 292 in e67a84f

	acquireConnection :: IORef (Maybe Connection) -> IO Connection
	acquireConnection r = do
	possible <- readIORef r
	case possible of
	Nothing -> do
	ctx <- baselineContextSSL
	c <- openConnectionSSL ctx "api.honeycomb.io" 443
	writeIORef r (Just c)
	pure c
	Just c -> do
	pure c
	cleanupConnection :: IORef (Maybe Connection) -> IO ()
	cleanupConnection r = do
	Safe.finally
	( do
	possible <- readIORef r
	case possible of
	Nothing -> pure ()
	Just c -> closeConnection c
	)
	( do
	writeIORef r Nothing
	)
	compressBody :: Bytes -> OutputStream Builder -> IO ()
	compressBody bytes o = do
	let x = fromBytes bytes
	let x' = GZip.compress x
	let b = Builder.lazyByteString x'
	Streams.write (Just b) o
	postEventToHoneycombAPI :: IORef (Maybe Connection) -> ApiKey -> Dataset -> JsonValue -> IO ()
	postEventToHoneycombAPI r apikey dataset json = attempt False
	where
	attempt retrying = do
	Safe.catch
	( do
	c <- acquireConnection r
	-- actually transmit telemetry to Honeycomb
	sendRequest c q (compressBody (encodeToUTF8 json))
	receiveResponse c handler
	)
	( \(e :: SomeException) -> do
	-- ideally we don't get here, but if the SSL connection collapses
	-- we will. We retry /once/, and otherwise throw the exception out.
	cleanupConnection r
	case retrying of
	False -> do
	putStrLn "internal: Reconnecting to Honeycomb"
	attempt True
	True -> do
	putStrLn "internal: Failed to re-establish connection to Honeycomb"
	Safe.throw e
	)
	q = buildRequest1 $ do
	http POST (fromRope ("/1/batch/" <> dataset))
	setContentType "application/json"
	setHeader "Content-Encoding" "gzip"
	setHeader "X-Honeycomb-Team" (fromRope (apikey))
	{-
	Response to Batch API looks like:
	[{"status":202}]
	TODO we need to handle other status responses properly.
	-}
	handler :: Response -> InputStream ByteString -> IO ()
	handler p i = do
	let code = getStatusCode p
	case code of
	200 -> do
	body <- simpleHandler p i

[istathar]

(an equally helpful outcome of this discussion would be "it's fine!" but I'd love someone else to weigh in)

[jaesharp]

Taking a look at this, but I want to load up some context so it may take me a little bit to get back to you.