S3 export (untested)

It opens a http connection per file exported, but then so does git
annex copy --to s3.

Decided not to munge exported filenames for IA. Too large a chance of
the munging having confusing results. Instead, export of files not
supported by IA, eg with spaces in their name, will fail.

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

5 files changed, 119 insertions, 62 deletions

diff --git a/CHANGELOG b/CHANGELOG
index b1701082c..137e4e970 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -4,7 +4,7 @@ git-annex (6.20170819) UNRELEASED; urgency=medium
     exports of trees to special remotes.
   * Use git-annex initremote with exporttree=yes to set up a special remote
     for use by git-annex export.
-  * Implemented export to directory special remotes.
+  * Implemented export to directory and S3 special remotes.
   * External special remote protocol extended to support export.
   * Support building with feed-1.0, while still supporting older versions.
   * init: Display an additional message when it detects a filesystem that
diff --git a/Remote/S3.hs b/Remote/S3.hs
index 4b56cce29..96d24d00e 100644
--- a/Remote/S3.hs
+++ b/Remote/S3.hs
@@ -59,7 +59,7 @@ remote = RemoteType
 	, enumerate = const (findSpecialRemotes "s3")
 	, generate = gen
 	, setup = s3Setup
-	, exportSupported = exportUnsupported
+	, exportSupported = exportIsSupported
 	}
 
 gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
@@ -86,7 +86,13 @@ gen r u c gc = do
 			, lockContent = Nothing
 			, checkPresent = checkPresentDummy
 			, checkPresentCheap = False
-			, exportActions = exportUnsupported
+			, exportActions = ExportActions
+				{ storeExport = storeExportS3 this info
+				, retrieveExport = retrieveExportS3 this info
+				, removeExport = removeExportS3 this info
+				, checkPresentExport = checkPresentExportS3 this info
+				, renameExport = renameExportS3 this info
+				}
 			, whereisKey = Just (getWebUrls info)
 			, remoteFsck = Nothing
 			, repairRepo = Nothing
@@ -107,6 +113,7 @@ s3Setup :: SetupStage -> Maybe UUID -> Maybe CredPair -> RemoteConfig -> RemoteG
 s3Setup ss mu mcreds c gc = do
 	u <- maybe (liftIO genUUID) return mu
 	s3Setup' ss u mcreds c gc
+
 s3Setup' :: SetupStage -> UUID -> Maybe CredPair -> RemoteConfig -> RemoteGitConfig -> Annex (RemoteConfig, UUID)
 s3Setup' ss u mcreds c gc
 	| configIA c = archiveorg
@@ -170,25 +177,26 @@ prepareS3HandleMaybe r = resourcePrepare $ const $
 
 store :: Remote -> S3Info -> S3Handle -> Storer
 store _r info h = fileStorer $ \k f p -> do
-	case partSize info of
-		Just partsz | partsz > 0 -> do
-			fsz <- liftIO $ getFileSize f
-			if fsz > partsz
-				then multipartupload fsz partsz k f p
-				else singlepartupload k f p
-		_ -> singlepartupload k f p	
+	storeHelper info h f (T.pack $ bucketObject info k) p
 	-- Store public URL to item in Internet Archive.
 	when (isIA info && not (isChunkKey k)) $
 		setUrlPresent webUUID k (iaPublicKeyUrl info k)
 	return True
+
+storeHelper :: S3Info -> S3Handle -> FilePath -> S3.Object -> MeterUpdate -> Annex ()
+storeHelper info h f object p = case partSize info of
+	Just partsz | partsz > 0 -> do
+		fsz <- liftIO $ getFileSize f
+		if fsz > partsz
+			then multipartupload fsz partsz
+			else singlepartupload
+	_ -> singlepartupload
   where
-	singlepartupload k f p = do
+	singlepartupload = do
 		rbody <- liftIO $ httpBodyStorer f p
-		void $ sendS3Handle h $ putObject info (T.pack $ bucketObject info k) rbody
-	multipartupload fsz partsz k f p = do
+		void $ sendS3Handle h $ putObject info object rbody
+	multipartupload fsz partsz = do
 #if MIN_VERSION_aws(0,10,6)
-		let object = T.pack (bucketObject info k)
-
 		let startreq = (S3.postInitiateMultipartUpload (bucket info) object)
 				{ S3.imuStorageClass = Just (storageClass info)
 				, S3.imuMetadata = metaHeaders info
@@ -227,16 +235,27 @@ store _r info h = fileStorer $ \k f p -> do
 			(bucket info) object uploadid (zip [1..] etags)
 #else
 		warning $ "Cannot do multipart upload (partsize " ++ show partsz ++ ") of large file (" ++ show fsz ++ "); built with too old a version of the aws library."
-		singlepartupload k f p
+		singlepartupload
 #endif
 
 {- Implemented as a fileRetriever, that uses conduit to stream the chunks
  - out to the file. Would be better to implement a byteRetriever, but
  - that is difficult. -}
 retrieve :: Remote -> S3Info -> Maybe S3Handle -> Retriever
-retrieve _ info (Just h) = fileRetriever $ \f k p -> liftIO $ runResourceT $ do
+retrieve _ info (Just h) = fileRetriever $ \f k p ->
+	retrieveHelper info h (T.pack $ bucketObject info k) f p
+retrieve r info Nothing = case getpublicurl info of
+	Nothing -> \_ _ _ -> do
+		warnMissingCredPairFor "S3" (AWS.creds $ uuid r)
+		return False
+	Just geturl -> fileRetriever $ \f k p ->
+		unlessM (downloadUrl k p [geturl k] f) $
+			giveup "failed to download content"
+
+retrieveHelper :: S3Info -> S3Handle -> S3.Object -> FilePath -> MeterUpdate -> Annex ()
+retrieveHelper info h object f p = liftIO $ runResourceT $ do
 	(fr, fh) <- allocate (openFile f WriteMode) hClose
-	let req = S3.getObject (bucket info) (T.pack $ bucketObject info k)
+	let req = S3.getObject (bucket info) object
 	S3.GetObjectResponse { S3.gorResponse = rsp } <- sendS3Handle' h req
 	responseBody rsp $$+- sinkprogressfile fh p zeroBytesProcessed
 	release fr
@@ -251,13 +270,6 @@ retrieve _ info (Just h) = fileRetriever $ \f k p -> liftIO $ runResourceT $ do
 					void $ meterupdate sofar'
 					S.hPut fh bs
 				sinkprogressfile fh meterupdate sofar'
-retrieve r info Nothing = case getpublicurl info of
-	Nothing -> \_ _ _ -> do
-		warnMissingCredPairFor "S3" (AWS.creds $ uuid r)
-		return False
-	Just geturl -> fileRetriever $ \f k p ->
-		unlessM (downloadUrl k p [geturl k] f) $
-			giveup "failed to download content"
 
 retrieveCheap :: Key -> AssociatedFile -> FilePath -> Annex Bool
 retrieveCheap _ _ _ = return False
@@ -276,8 +288,19 @@ remove info h k
 		return $ either (const False) (const True) res
 
 checkKey :: Remote -> S3Info -> Maybe S3Handle -> CheckPresent
+checkKey r info Nothing k = case getpublicurl info of
+	Nothing -> do
+		warnMissingCredPairFor "S3" (AWS.creds $ uuid r)
+		giveup "No S3 credentials configured"
+	Just geturl -> do
+		showChecking r
+		withUrlOptions $ checkBoth (geturl k) (keySize k)
 checkKey r info (Just h) k = do
 	showChecking r
+	checkKeyHelper info h (T.pack $ bucketObject info k)
+
+checkKeyHelper :: S3Info -> S3Handle -> S3.Object -> Annex Bool
+checkKeyHelper info h object = do
 #if MIN_VERSION_aws(0,10,0)
 	rsp <- go
 	return (isJust $ S3.horMetadata rsp)
@@ -287,8 +310,7 @@ checkKey r info (Just h) k = do
 		return True
 #endif
   where
-	go = sendS3Handle h $
-		S3.headObject (bucket info) (T.pack $ bucketObject info k)
+	go = sendS3Handle h $ S3.headObject (bucket info) object
 
 #if ! MIN_VERSION_aws(0,10,0)
 	{- Catch exception headObject returns when an object is not present
@@ -303,13 +325,50 @@ checkKey r info (Just h) k = do
 			| otherwise = Nothing
 #endif
 
-checkKey r info Nothing k = case getpublicurl info of
-	Nothing -> do
-		warnMissingCredPairFor "S3" (AWS.creds $ uuid r)
-		giveup "No S3 credentials configured"
-	Just geturl -> do
-		showChecking r
-		withUrlOptions $ checkBoth (geturl k) (keySize k)
+storeExportS3 :: Remote -> S3Info -> FilePath -> Key -> ExportLocation -> MeterUpdate -> Annex Bool
+storeExportS3 r info f _k loc p = 
+	catchNonAsync go (\e -> warning (show e) >> return False)
+  where
+	go = withS3Handle (config r) (gitconfig r) (uuid r) $ \h -> do
+		storeHelper info h f (T.pack $ bucketExportLocation info loc) p
+		return True
+
+retrieveExportS3 :: Remote -> S3Info -> Key -> ExportLocation -> FilePath -> MeterUpdate -> Annex Bool
+retrieveExportS3 r info _k loc f p =
+	catchNonAsync go (\e -> warning (show e) >> return False)
+  where
+	go = withS3Handle (config r) (gitconfig r) (uuid r) $ \h -> do
+		retrieveHelper info h (T.pack $ bucketExportLocation info loc) f p
+		return True
+
+removeExportS3 :: Remote -> S3Info -> Key -> ExportLocation -> Annex Bool
+removeExportS3 r info _k loc = 
+	catchNonAsync go (\e -> warning (show e) >> return False)
+  where
+	go = withS3Handle (config r) (gitconfig r) (uuid r) $ \h -> do
+		res <- tryNonAsync $ sendS3Handle h $
+			S3.DeleteObject (T.pack $ bucketExportLocation info loc) (bucket info)
+		return $ either (const False) (const True) res
+
+checkPresentExportS3 :: Remote -> S3Info -> Key -> ExportLocation -> Annex Bool
+checkPresentExportS3 r info _k loc = 
+	catchNonAsync go (\e -> warning (show e) >> return False)
+  where
+	go = withS3Handle (config r) (gitconfig r) (uuid r) $ \h -> do
+		checkKeyHelper info h (T.pack $ bucketExportLocation info loc)
+
+renameExportS3 :: Remote -> S3Info -> Key -> ExportLocation -> ExportLocation -> Annex Bool
+renameExportS3 r info _k src dest = catchNonAsync go (\e -> warning (show e) >> return False)
+  where
+	go = withS3Handle (config r) (gitconfig r) (uuid r) $ \h -> do
+		-- S3 has no move primitive; copy and delete.
+		void $ sendS3Handle h $ S3.copyObject (bucket info) dstobject
+			(S3.ObjectId (bucket info) srcobject Nothing)
+			S3.CopyMetadata
+		void $ sendS3Handle h $ S3.DeleteObject srcobject (bucket info)
+		return True
+	srcobject = T.pack $ bucketExportLocation info src
+	dstobject = T.pack $ bucketExportLocation info dest
 
 {- Generate the bucket if it does not already exist, including creating the
  - UUID file within the bucket.
@@ -474,6 +533,7 @@ data S3Info = S3Info
 	{ bucket :: S3.Bucket
 	, storageClass :: S3.StorageClass
 	, bucketObject :: Key -> String
+	, bucketExportLocation :: ExportLocation -> String
 	, metaHeaders :: [(T.Text, T.Text)]
 	, partSize :: Maybe Integer
 	, isIA :: Bool
@@ -491,6 +551,7 @@ extractS3Info c = do
 		{ bucket = b
 		, storageClass = getStorageClass c
 		, bucketObject = getBucketObject c
+		, bucketExportLocation = getBucketExportLocation c
 		, metaHeaders = getMetaHeaders c
 		, partSize = getPartSize c
 		, isIA = configIA c
@@ -554,6 +615,9 @@ getBucketObject c = munge . key2file
 		Just "ia" -> iaMunge $ getFilePrefix c ++ s
 		_ -> getFilePrefix c ++ s
 
+getBucketExportLocation :: RemoteConfig -> ExportLocation -> FilePath
+getBucketExportLocation c (ExportLocation loc) = getFilePrefix c ++ loc
+
 {- Internet Archive limits filenames to a subset of ascii,
  - with no whitespace. Other characters are xml entity
  - encoded. -}
diff --git a/doc/special_remotes/S3.mdwn b/doc/special_remotes/S3.mdwn
index d526d35f5..138105f1d 100644
--- a/doc/special_remotes/S3.mdwn
+++ b/doc/special_remotes/S3.mdwn
@@ -66,6 +66,10 @@ the S3 remote.
   so by default, a bucket name is chosen based on the remote name
   and UUID. This can be specified to pick a bucket name.
 
+* `exporttree` - Set to "yes" to make this special remote usable
+  by [[git-annex-export]]. It will not be usable as a general-purpose
+  special remote.
+
 * `public` - Set to "yes" to allow public read access to files sent
   to the S3 remote. This is accomplished by setting an ACL when each 
   file is uploaded to the remote. So, changes to this setting will
diff --git a/doc/tips/Internet_Archive_via_S3.mdwn b/doc/tips/Internet_Archive_via_S3.mdwn
index 15f241c9f..20d14bdec 100644
--- a/doc/tips/Internet_Archive_via_S3.mdwn
+++ b/doc/tips/Internet_Archive_via_S3.mdwn
@@ -55,31 +55,14 @@ from it. Also, git-annex whereis will tell you a public url for the file
 on archive.org. (It may take a while for archive.org to make the file
 publically visibile.)
 
-Note the use of the SHA256E [[backend|backends]] when adding files. That is
-the default backend used by git-annex, but even if you don't normally use
-it, it makes most sense to use the WORM or SHA256E backend for files that
-will be stored in the Internet Archive, since the key name will be exposed
-as the filename there, and since the Archive does special processing of
-files based on their extension.
+## exporting trees
 
-## publishing only one subdirectory
+By default, files stored in the Internet Archive will show up there named
+by their git-annex key, not the original filename. If the filenames
+are important, you can run `git annex initremote` with an additional
+parameter "exporttree=yes", and then use [[git-annex-export]] to publish
+a tree of files to the Internet Archive.
 
-Perhaps you have a repository with lots of files in it, and only want
-to publish some of them to a particular Internet Archive item. Of course
-you can specify which files to send manually, but it's useful to
-configure [[preferred_content]] settings so git-annex knows what content
-you want to store in the Internet Archive.
-
-One way to do this is using the "public" repository type.
-
-	git annex enableremote archive-panama preferreddir=panama
-	git annex wanted archive-panama standard
-	git annex group archive-panama public
-
-Now anything in a "panama" directory will be sent to that remote,
-and anything else won't. You can use `git annex copy --auto` or the
-assistant and it'll do the right thing.
-
-When setting up an Internet Archive item using the webapp, this
-configuration is automatically done, using an item name that the user
-enters as the name of the subdirectory.
+Note that the Internet Archive does not support filenames containing
+whitespace and some other characters. Exporting such problem filenames will
+fail; you can rename the file and re-export.
diff --git a/doc/todo/export.mdwn b/doc/todo/export.mdwn
index 7a94cd1c8..535678c2a 100644
--- a/doc/todo/export.mdwn
+++ b/doc/todo/export.mdwn
@@ -24,8 +24,14 @@ Work is in progress. Todo list:
   export from another repository also doesn't work right, because the
   export database is not populated. So, seems that the export database needs
   to get populated based on the export log in these cases.
-* Support export to aditional special remotes (S3 etc)
-* Support export to external special remotes.
+* Support export to aditional special remotes (webdav etc)
+* Support export in the assistant (when eg setting up a S3 special remote).
+  Would need git-annex sync to export to the master tree?
+  This is similar to the little-used preferreddir= preferred content
+  setting and the "public" repository group.
+* Test S3 export.
+* Test export to IA via S3. In particualar, does removing an exported file
+  work?
 
 Low priority: