map: Support --json option

Sponsored-by: Dartmouth College's OpenNeuro project

CHANGELOG

@@ -6,6 +6,7 @@ git-annex (10.20250521) UNRELEASED; urgency=medium
     configured but fails, prevent initialization. This allows the user to
     fix their configuration and avoid crippled filesystem detection
     entering an adjusted branch.
+  * map: Support --json option.
 
  -- Joey Hess <id@joeyh.name>  Thu, 22 May 2025 12:43:38 -0400
 

Command/Map.hs

@@ -9,8 +9,6 @@
 
 module Command.Map where
 
-import qualified Data.Map as M
-
 import Command
 import qualified Git
 import qualified Git.Url
@@ -25,12 +23,17 @@ import Logs.Trust
 import Types.TrustLevel
 import qualified Remote.Helper.Ssh as Ssh
 import qualified Utility.Dot as Dot
+import qualified Messages.JSON as JSON
+import Messages.JSON ((.=))
+import Utility.Aeson (packString)
+
+import qualified Data.Map as M
 
 -- a repo and its remotes
 type RepoRemotes = (Git.Repo, [Git.Repo])
 
 cmd :: Command
-cmd = dontCheck repoExists $
+cmd = dontCheck repoExists $ withAnnexOptions [jsonOptions] $
 	command "map" SectionQuery
 		"generate map of repositories"
 		paramNothing (withParams seek)
@@ -45,6 +48,9 @@ start = startingNoMessage (ActionItemOther Nothing) $ do
 	umap <- uuidDescMap
 	trustmap <- trustMapLoad
 		
+	ifM (outputJSONMap rs trustmap umap)
+		( next $ return True
+		, do
 			file <- (</>)
 				<$> fromRepo gitAnnexDir
 				<*> pure (literalOsPath "map.dot")
@@ -58,6 +64,7 @@ start = startingNoMessage (ActionItemOther Nothing) $ do
 						, ("dot", [Param "-Tx11", File (fromOsPath file)])
 						]	
 					)
+		)
 
 runViewer :: OsPath -> [(String, [CommandParam])] -> Annex Bool
 runViewer file [] = do
@@ -198,6 +205,7 @@ same a b
 {- reads the config of a remote, with progress display -}
 scan :: Git.Repo -> Annex Git.Repo
 scan r = do
+	unlessM jsonOutputEnabled $
 		showStartMessage (StartMessage "map" (ActionItemOther (Just $ UnquotedString $ Git.repoDescribe r)) (SeekInput []))
 	v <- tryScan r
 	case v of
@@ -269,7 +277,7 @@ tryScan r
 				configlist
 			ok -> return ok
 
-	sshnote = do
+	sshnote = unlessM jsonOutputEnabled $ do
 		showAction "sshing"
 		showOutput
 
@@ -287,3 +295,33 @@ safely a = do
 	case result of
 		Left _ -> return Nothing
 		Right r' -> return $ Just r'
+
+outputJSONMap :: [RepoRemotes] -> TrustMap -> UUIDDescMap -> Annex Bool
+outputJSONMap rs trustmap umap = 
+	showFullJSON $ JSON.AesonObject $ case mapo of
+		JSON.Object obj -> obj
+		_ -> error "internal"
+  where
+	mapo = JSON.object
+		[ "nodes" .= map mknode (filterdead fst rs)
+		]
+	
+	mknode (r, remotes) = JSON.object
+		[ "name" .= packString (repoName umap r)
+		, "uuid" .= mkuuid (getUncachedUUID r)
+		, "url" .= packString (Git.repoLocation r)
+		, "remotes" .= map mkremote (filterdead id remotes)
+		]
+	
+	mkremote r = JSON.object
+		[ "name" .= packString (repoName umap r)
+		, "uuid" .= mkuuid (getUncachedUUID r)
+		, "url" .= packString (Git.repoLocation r)
+		]
+	
+	mkuuid NoUUID = Nothing
+	mkuuid u = Just $ packString $ fromUUID u
+	
+	filterdead f = filter
+		(\i -> M.lookup (getUncachedUUID (f i)) trustmap /= Just DeadTrusted)
+

doc/git-annex-map.mdwn

@@ -39,6 +39,10 @@ on that host.
 
   Don't display the generated Graphviz file, but save it for later use.
 
+* `--json`
+
+  Output the map as a JSON object.
+
 * Also the [[git-annex-common-options]](1) can be used.
 
 # SEE ALSO

doc/todo/map__58___add_--json.mdwn

@@ -6,3 +6,5 @@ Please let me know on how feasible that would be, and any other thoughts you hav
 
 [[!meta author=yoh]]
 [[!tag projects/openneuro]]
+
+> [[done]] --[[Joey]]

doc/todo/map__58___add_--json/comment_2_e9d4957cf5a3d5c015108cb1805df7da._comment

@@ -0,0 +1,51 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 2"""
+ date="2025-05-28T18:11:34Z"
+ content="""
+I went ahead and implemented `git-annx map --json`.
+
+Example output, after being passed through `jq` to pretty-print it:
+
+	{
+	  "nodes": [
+	    {
+	      "name": "joey@darkstar:~/tmp/mapbench/a",
+	      "remotes": [
+	        {
+	          "name": "joey@darkstar:~/tmp/mapbench/b",
+	          "url": "/home/joey/tmp/mapbench/b",
+	          "uuid": "645d92d8-6461-43c1-b23c-6dd04dc3a015"
+	        }
+	      ],
+	      "url": "/home/joey/tmp/mapbench/a",
+	      "uuid": "3f34e4c2-dd19-433a-ab04-9fd4be959325"
+	    },
+	    {
+	      "name": "joey@darkstar:~/tmp/mapbench/b",
+	      "remotes": [
+	        {
+	          "name": "joey@darkstar:~/tmp/mapbench/a",
+	          "url": "/home/joey/tmp/mapbench/a",
+	          "uuid": "3f34e4c2-dd19-433a-ab04-9fd4be959325"
+	        }
+	      ],
+	      "url": "/home/joey/tmp/mapbench/b",
+	      "uuid": "645d92d8-6461-43c1-b23c-6dd04dc3a015"
+	    },
+	    {
+	      "name": "unknown",
+	      "remotes": [
+	        {
+	          "name": "joey@darkstar:~/tmp/mapbench/b",
+	          "url": "/home/joey/tmp/mapbench/b",
+	          "uuid": "645d92d8-6461-43c1-b23c-6dd04dc3a015"
+	        }
+	      ],
+	      "url": ".",
+	      "uuid": null
+	    }
+	  ],
+	  "error-messages": []
+	}
+"""]]