better HTTP connection reuse

Enable HTTP connection reuse across multiple files, when git-annex
uses http-conduit. Before, a new Manager was created each time
Utility.Url used it. Now, a single Manager gets created the first time,
so connections are reused.

Doesn't help when external programs are used for url download,
but does speed up addurl --fast, fsck --from web, etc.

Testing fsck --fast --from web with 3 files, over high-latency
satellite internet, it sped up from 19.37s to 14.96s.

This commit was supported by the NSF-funded DataLad project.

Annex/Content.hs

@@ -947,8 +947,8 @@ downloadUrl k p urls file = meteredFile file (Just p) k $
 			( return Url.downloadQuiet
 			, return Url.download
 			)
-		Url.withUrlOptions $ \uo ->
-			anyM (\u -> a u file uo) urls
+		Url.withUrlOptions $ \uo -> 
+			liftIO $ anyM (\u -> a u file uo) urls
 	go (Just basecmd) = anyM (downloadcmd basecmd) urls
 	downloadcmd basecmd url =
 		progressCommand "sh" [Param "-c", Param $ gencmd url basecmd]

Annex/Url.hs

@@ -9,6 +9,7 @@
 module Annex.Url (
 	module U,
 	withUrlOptions,
+	getUrlOptions,
 	getUserAgent,
 ) where
 
@@ -24,20 +25,24 @@ getUserAgent :: Annex (Maybe U.UserAgent)
 getUserAgent = Annex.getState $ 
 	Just . fromMaybe defaultUserAgent . Annex.useragent
 
-withUrlOptions :: (U.UrlOptions -> Annex a) -> Annex a
-withUrlOptions a = Annex.getState Annex.urloptions >>= \case
-	Just uo -> a uo
+getUrlOptions :: Annex U.UrlOptions
+getUrlOptions = Annex.getState Annex.urloptions >>= \case
+	Just uo -> return uo
 	Nothing -> do
 		uo <- mk
 		Annex.changeState $ \s -> s
 			{ Annex.urloptions = Just uo }
-		a uo
+		return uo
   where
 	mk = mkUrlOptions
 		<$> getUserAgent
 		<*> headers
 		<*> options
+		<*> liftIO (U.newManager U.managerSettings)
 	headers = annexHttpHeadersCommand <$> Annex.getGitConfig >>= \case
 		Just cmd -> lines <$> liftIO (readProcess "sh" ["-c", cmd])
 		Nothing -> annexHttpHeaders <$> Annex.getGitConfig
 	options = map Param . annexWebOptions <$> Annex.getGitConfig
+
+withUrlOptions :: (U.UrlOptions -> Annex a) -> Annex a
+withUrlOptions a = a =<< getUrlOptions

Assistant/Restart.hs

@@ -95,7 +95,7 @@ newAssistantUrl repo = do
  - warp-tls listens to http, in order to show an error page, so this works.
  -}
 assistantListening :: URLString -> IO Bool
-assistantListening url = catchBoolIO $ exists url' def
+assistantListening url = catchBoolIO $ exists url' =<< defUrlOptions
   where
 	url' = case parseURI url of
 		Nothing -> url

Assistant/Upgrade.hs

@@ -316,7 +316,8 @@ usingDistribution :: IO Bool
 usingDistribution = isJust <$> getEnv "GIT_ANNEX_STANDLONE_ENV"
 
 downloadDistributionInfo :: Assistant (Maybe GitAnnexDistribution)
-downloadDistributionInfo = Url.withUrlOptions $ \uo -> do
+downloadDistributionInfo = do
+	uo <- liftAnnex Url.getUrlOptions
 	gpgcmd <- liftAnnex $ gpgCmd <$> Annex.getGitConfig
 	liftIO $ withTmpDir "git-annex.tmp" $ \tmpdir -> do
 		let infof = tmpdir </> "info"

Assistant/WebApp/Configurators/IA.hs

@@ -189,7 +189,8 @@ escapeHeader :: String -> String
 escapeHeader = escapeURIString (\c -> isUnescapedInURI c && c /= ' ')
 
 getRepoInfo :: RemoteConfig -> Widget
-getRepoInfo c = Url.withUrlOptions $ \uo ->
+getRepoInfo c = do
+	uo <- liftAnnex Url.getUrlOptions
 	exists <- liftIO $ catchDefaultIO False $ Url.exists url uo
 	[whamlet|
 <a href="#{url}">

CHANGELOG

@@ -12,6 +12,8 @@ git-annex (6.20180317) UNRELEASED; urgency=medium
     don't copy the data metadata from the old version of the file,
     instead use the mtime of the file.
   * Avoid running annex.http-headers-command more than once.
+  * Enable HTTP connection reuse across multiple files, when git-annex
+    uses http-conduit.
 
  -- Joey Hess <id@joeyh.name>  Mon, 19 Mar 2018 23:13:59 -0400
 

Command/AddUrl.hs

@@ -196,7 +196,8 @@ startWeb o urlstring = go $ fromMaybe bad $ parseURI urlstring
 		pathmax <- liftIO $ fileNameLengthLimit "."
 		urlinfo <- if relaxedOption (downloadOptions o)
 			then pure Url.assumeUrlExists
-			else Url.withUrlOptions (Url.getUrlInfo urlstring)
+			else Url.withUrlOptions $
+				liftIO . Url.getUrlInfo urlstring
 		file <- adjustFile o <$> case fileOption (downloadOptions o) of
 			Just f -> pure f
 			Nothing -> case Url.urlSuggestedFile urlinfo of

Command/ImportFeed.hs

@@ -150,7 +150,7 @@ downloadFeed url
 	| Url.parseURIRelaxed url == Nothing = giveup "invalid feed url"
 	| otherwise = do
 		showOutput
-		Url.withUrlOptions $ \ou ->
+		Url.withUrlOptions $ \uo ->
 			liftIO $ withTmpFile "feed" $ \f h -> do
 				hClose h
 				ifM (Url.download url f uo)
@@ -167,7 +167,8 @@ performDownload opts cache todownload = case location todownload of
 				then do
 					urlinfo <- if relaxedOption (downloadOptions opts)
 						then pure Url.assumeUrlExists
-						else Url.withUrlOptions (Url.getUrlInfo url)
+						else Url.withUrlOptions $
+							liftIO . Url.getUrlInfo url
 					let dlopts = (downloadOptions opts)
 						-- force using the filename
 						-- chosen here

Remote/Git.hs

@@ -336,10 +336,11 @@ inAnnex rmt (State connpool duc) key
 	r = repo rmt
 	checkhttp = do
 		showChecking r
-		ifM (Url.withUrlOptions $ \uo -> anyM (\u -> Url.checkBoth u (keySize key) uo) (keyUrls rmt key))
-			( return True
-			, giveup "not found"
-			)
+		ifM (Url.withUrlOptions $ \uo -> liftIO $
+			anyM (\u -> Url.checkBoth u (keySize key) uo) (keyUrls rmt key))
+				( return True
+				, giveup "not found"
+				)
 	checkremote = 
 		let fallback = Ssh.inAnnex r key
 		in P2PHelper.checkpresent (Ssh.runProto rmt connpool (cantCheck rmt) fallback) key

Remote/S3.hs

@@ -1,6 +1,6 @@
 {- S3 remotes
  -
- - Copyright 2011-2017 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2018 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -22,7 +22,7 @@ import qualified Data.ByteString as S
 import qualified Data.Map as M
 import Data.Char
 import Network.Socket (HostName)
-import Network.HTTP.Conduit (Manager, newManager)
+import Network.HTTP.Conduit (Manager)
 import Network.HTTP.Client (responseStatus, responseBody, RequestBody(..))
 import Network.HTTP.Types
 import Control.Monad.Trans.Resource
@@ -51,7 +51,7 @@ import Utility.DataUnits
 import Utility.FileSystemEncoding
 import Annex.Content
 import Annex.Url (withUrlOptions)
-import Utility.Url (checkBoth, managerSettings, closeManager)
+import Utility.Url (checkBoth, UrlOptions(..))
 
 type BucketName = String
 
@@ -295,7 +295,7 @@ checkKey r info Nothing k = case getpublicurl info of
 		giveup "No S3 credentials configured"
 	Just geturl -> do
 		showChecking r
-		withUrlOptions $ checkBoth (geturl k) (keySize k)
+		withUrlOptions $ liftIO . checkBoth (geturl k) (keySize k)
 checkKey r info (Just h) k = do
 	showChecking r
 	checkKeyHelper info h (T.pack $ bucketObject info k)
@@ -500,8 +500,8 @@ withS3HandleMaybe c gc u a = do
 #if MIN_VERSION_aws(0,17,0)
 				Nothing
 #endif
-			bracketIO (newManager managerSettings) closeManager $ \mgr -> 
-				a $ Just $ S3Handle mgr awscfg s3cfg
+			withUrlOptions $ \ou ->
+				a $ Just $ S3Handle (httpManager ou) awscfg s3cfg
 		Nothing -> a Nothing
   where
 	s3cfg = s3Configuration c

Utility/Url.hs

@@ -1,6 +1,6 @@
 {- Url downloading.
  -
- - Copyright 2011-2017 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2018 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -11,11 +11,12 @@
 {-# LANGUAGE FlexibleContexts #-}
 
 module Utility.Url (
-	closeManager,
+	newManager,
 	managerSettings,
 	URLString,
 	UserAgent,
-	UrlOptions,
+	UrlOptions(..),
+	defUrlOptions,
 	mkUrlOptions,
 	check,
 	checkBoth,
@@ -42,18 +43,9 @@ import qualified Data.ByteString as B
 import qualified Data.ByteString.UTF8 as B8
 import qualified Data.ByteString.Lazy as L
 import Control.Monad.Trans.Resource
-import Network.HTTP.Conduit hiding (closeManager)
+import Network.HTTP.Conduit
 import Network.HTTP.Client (brRead, withResponse)
 
--- closeManager is needed with older versions of http-client,
--- but not new versions, which warn about using it. Urgh.
-#if ! MIN_VERSION_http_client(0,4,18)
-import Network.HTTP.Client (closeManager)
-#else
-closeManager :: Manager -> IO ()
-closeManager _ = return ()
-#endif
-
 #if ! MIN_VERSION_http_client(0,5,0)
 responseTimeoutNone :: Maybe Int
 responseTimeoutNone = Nothing
@@ -78,15 +70,20 @@ data UrlOptions = UrlOptions
 	, reqHeaders :: Headers
 	, reqParams :: [CommandParam]
 	, applyRequest :: Request -> Request
+	, httpManager :: Manager
 	}
 
-instance Default UrlOptions
-  where
-	def = UrlOptions Nothing [] [] id
+defUrlOptions :: IO UrlOptions
+defUrlOptions = UrlOptions
+	<$> pure Nothing
+	<*> pure []
+	<*> pure []
+	<*> pure id
+	<*> newManager managerSettings
 
-mkUrlOptions :: Maybe UserAgent -> Headers -> [CommandParam] -> UrlOptions
-mkUrlOptions defuseragent reqheaders reqparams =
-	UrlOptions useragent reqheaders reqparams applyrequest
+mkUrlOptions :: Maybe UserAgent -> Headers -> [CommandParam] -> Manager -> UrlOptions
+mkUrlOptions defuseragent reqheaders reqparams manager =
+	UrlOptions useragent reqheaders reqparams applyrequest manager
   where
 	applyrequest = \r -> r { requestHeaders = requestHeaders r ++ addedheaders }
 	addedheaders = uaheader ++ otherheaders
@@ -118,7 +115,7 @@ checkBoth url expected_size uo = do
 	return (fst v && snd v)
 
 check :: URLString -> Maybe Integer -> UrlOptions -> IO (Bool, Bool)
-check url expected_size = go <$$> getUrlInfo url
+check url expected_size uo = go <$> getUrlInfo url uo
   where
 	go (UrlInfo False _ _) = (False, False)
 	go (UrlInfo True Nothing _) = (True, True)
@@ -192,19 +189,16 @@ getUrlInfo url uo = case parseURIRelaxed url of
 		filter (\p -> fst p == h) . responseHeaders
 
 	existsconduit req = do
-		mgr <- newManager managerSettings
 		let req' = headRequest (applyRequest uo req)
-		ret <- runResourceT $ do
-			resp <- http req' mgr
-			-- forces processing the response before the
-			-- manager is closed
+		runResourceT $ do
+			resp <- http req' (httpManager uo)
+			-- forces processing the response while
+			-- within the runResourceT
 			liftIO $ if responseStatus resp == ok200
 				then found
 					(extractlen resp)
 					(extractfilename resp)
 				else dne
-		liftIO $ closeManager mgr
-		return ret
 
 	existscurl u = do
 		output <- catchDefaultIO "" $
@@ -327,14 +321,11 @@ downloadPartial url uo n = case parseURIRelaxed url of
 	go u = case parseUrlConduit (show u) of
 		Nothing -> return Nothing
 		Just req -> do
-			mgr <- newManager managerSettings
 			let req' = applyRequest uo req
-			ret <- withResponse req' mgr $ \resp ->
+			withResponse req' (httpManager uo) $ \resp ->
 				if responseStatus resp == ok200
 					then Just <$> brread n [] (responseBody resp)
 					else return Nothing
-			liftIO $ closeManager mgr
-			return ret
 
 	-- could use brReadSome here, needs newer http-client dependency
 	brread n' l rb

doc/todo/stop_using_curl_and_wget.mdwn

@@ -12,6 +12,11 @@ and pipelining requests, so it makes mass url downloads a lot slower than
 if git-annex used http-conduit to do url downloads itself. [[users/yoh]]
 has requested http pipelining.
 
+(git-annex was creating a new http manager each time it hit an url,
+except for in the S3 remote which reused a single manager. That's now been
+improved, so all http-conduit use in git-annex reuses a http manager, and
+so will do http pipelining.)
+
 For file: ftp: and more unusual urls, http-conduit can't support them.
 git-annex does support those urls, and people rely on that, so it would
 still need to use wget or curl for those.