diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Revision history for nvfetcher
 
+## 0.7.0.0
+
+Now nvfetcher removes all files *except* `generated.json` and `generated.nix` in `_sources` before each run. If you do want to keep those files, you can use the new CLI option `--keep-old`. In addition, a new target `purge` is introduced for resetting the state of nvfetcher by deleting the shake database saved in XDG directory. 
+
+* Quote package name passed to nvchecker
+* Add `url.name` option to specify the file name in prefetch
+* Clean build dir before build
+* Support keep going on fetch failure
+* Add `--commit-summary`
+* Support sparseCheckout
+
 ## 0.6.2.0
 
 * Rework config parsing with toml-reader
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -103,10 +103,11 @@
 To run nvfetcher as a CLI program, you'll need to provide package sources defined in TOML.
 
 ```
-Usage: nvfetcher [--version] [--help] [-o|--build-dir DIR] [--commit-changes]
-                 [-l|--changelog FILE] [-j NUM] [-r|--retry NUM] [-t|--timing]
-                 [-v|--verbose] [-f|--filter REGEX] [-k|--keyfile FILE] [TARGET]
-                 [-c|--config FILE]
+Usage: nvfetcher [--version] [--help] [-o|--build-dir DIR] [--commit-changes] 
+                 [-l|--changelog FILE] [-j NUM] [-r|--retry NUM] [-t|--timing] 
+                 [-v|--verbose] [-f|--filter REGEX] [-k|--keyfile FILE] 
+                 [--keep-old] [--keep-going] [TARGET] [-c|--config FILE]
+
   generate nix sources expr for the latest version of packages
 
 Available options:
@@ -125,7 +126,11 @@
   -v,--verbose             Verbose mode
   -f,--filter REGEX        Regex to filter packages to be updated
   -k,--keyfile FILE        Nvchecker keyfile
-  TARGET                   Two targets are available: 1.build 2.clean
+  --keep-old               Don't remove old files other than generated json and
+                           nix before build
+  --keep-going             Don't stop if some packages failed to be fetched
+  TARGET                   Three targets are available: 1.build 2.clean (remove
+                           all generated files) 3.purge (remove shake db)
                            (default: build)
   -c,--config FILE         Path to nvfetcher TOML config
                            (default: "nvfetcher.toml")
@@ -188,8 +193,12 @@
 - `fetch.tarball = tarball_url`
 - `fetch.docker = owner/name`
 
-Optional `nix-prefetch fetchgit` config, which make sense only when the fetcher equals to `fetch.github` or `fetch.git`.
-They can exist simultaneously.
+Optional config for `nix-prefetch-url`, applies when the fetcher equals to `fetch.url`.
+`$ver` is available in string, just like for the fetch config.
+
+- `url.name = file_name`
+
+Optional config for `nix-prefetch-git`, applies when the fetcher equals to `fetch.github` or `fetch.git`.
 
 - `git.deepClone`
 - `git.fetchSubmodules`
diff --git a/app/Config.hs b/app/Config.hs
--- a/app/Config.hs
+++ b/app/Config.hs
@@ -78,6 +78,9 @@
             not $ null gk,
             "fetch.git" `notElem` keys && "fetch.github" `notElem` keys
         ]
+          <>
+          -- url
+          [KeyUnexpected pkg uk | let uk = filter ("url.name" ==) keys, not $ null uk, "fetch.url" `notElem` keys]
           -- docker
           <> [ KeyUnexpected pkg dk
                | let dk = filter (T.isPrefixOf "docker.") keys,
diff --git a/app/Config/Common.hs b/app/Config/Common.hs
--- a/app/Config/Common.hs
+++ b/app/Config/Common.hs
@@ -7,15 +7,15 @@
 import qualified Data.Text as T
 import TOML
 
-githubDecoder :: Decoder (Text, Text)
-githubDecoder = makeDecoder $ \case
+gitHubNameDecoder :: Decoder (Text, Text)
+gitHubNameDecoder = makeDecoder $ \case
   v@(String s) -> case T.split (== '/') s of
     [owner, repo] -> pure (owner, repo)
     _ -> invalidValue "unexpected github format: it should be in the format of [owner]/[repo]" v
   v -> typeMismatch v
 
-vscodeExtensionDecoder :: Decoder (Text, Text)
-vscodeExtensionDecoder = makeDecoder $ \case
+vscodeExtensionNameDecoder :: Decoder (Text, Text)
+vscodeExtensionNameDecoder = makeDecoder $ \case
   -- assume that we can't have '.' in extension's name
   v@(String s) -> case T.split (== '.') s of
     [publisher, extName] -> pure (publisher, extName)
diff --git a/app/Config/PackageFetcher.hs b/app/Config/PackageFetcher.hs
--- a/app/Config/PackageFetcher.hs
+++ b/app/Config/PackageFetcher.hs
@@ -50,7 +50,8 @@
 data GitOptions = GitOptions
   { goDeepClone :: Maybe Bool,
     goFetchSubmodules :: Maybe Bool,
-    goLeaveDotGit :: Maybe Bool
+    goLeaveDotGit :: Maybe Bool,
+    goSparseCheckout :: Maybe [Text]
   }
   deriving (Eq, Generic)
 
@@ -60,6 +61,7 @@
     <$> getFieldsOpt ["git", "deepClone"]
     <*> getFieldsOpt ["git", "fetchSubmodules"]
     <*> getFieldsOpt ["git", "leaveDotGit"]
+    <*> getFieldsOpt ["git", "sparseCheckout"]
 
 _GitOptions :: Traversal' (NixFetcher f) GitOptions
 _GitOptions f x@FetchGit {..} =
@@ -68,23 +70,25 @@
         & deepClone .~ fromMaybe False goDeepClone
         & fetchSubmodules .~ fromMaybe False goFetchSubmodules
         & leaveDotGit .~ fromMaybe False goLeaveDotGit
+        & sparseCheckout .~ fromMaybe [] goSparseCheckout
   )
-    <$> f (GitOptions (Just _deepClone) (Just _fetchSubmodules) (Just _leaveDotGit))
+    <$> f (GitOptions (Just _deepClone) (Just _fetchSubmodules) (Just _leaveDotGit) (Just _sparseCheckout))
 _GitOptions f x@FetchGitHub {..} =
   ( \GitOptions {..} ->
       x
         & deepClone .~ fromMaybe False goDeepClone
         & fetchSubmodules .~ fromMaybe False goFetchSubmodules
         & leaveDotGit .~ fromMaybe False goLeaveDotGit
+        & sparseCheckout .~ fromMaybe [] goSparseCheckout
   )
-    <$> f (GitOptions (Just _deepClone) (Just _fetchSubmodules) (Just _leaveDotGit))
+    <$> f (GitOptions (Just _deepClone) (Just _fetchSubmodules) (Just _leaveDotGit) (Just _sparseCheckout))
 _GitOptions _ x = pure x
 
 --------------------------------------------------------------------------------
 
 gitHubDecoder :: Decoder PackageFetcher
 gitHubDecoder = do
-  (owner, repo) <- getFieldsWith githubDecoder ["fetch", "github"]
+  (owner, repo) <- getFieldsWith gitHubNameDecoder ["fetch", "github"]
   gitOptions <- gitOptionsDecoder
   pure $ \v -> gitHubFetcher (owner, repo) v & _GitOptions .~ gitOptions
 
@@ -104,19 +108,20 @@
 --------------------------------------------------------------------------------
 
 openVsxDecoder :: Decoder PackageFetcher
-openVsxDecoder = openVsxFetcher <$> getFieldsWith vscodeExtensionDecoder ["fetch", "openvsx"]
+openVsxDecoder = openVsxFetcher <$> getFieldsWith vscodeExtensionNameDecoder ["fetch", "openvsx"]
 
 --------------------------------------------------------------------------------
 
 vscodeMarketplaceDecoder :: Decoder PackageFetcher
-vscodeMarketplaceDecoder = vscodeMarketplaceFetcher <$> getFieldsWith vscodeExtensionDecoder ["fetch", "vsmarketplace"]
+vscodeMarketplaceDecoder = vscodeMarketplaceFetcher <$> getFieldsWith vscodeExtensionNameDecoder ["fetch", "vsmarketplace"]
 
 --------------------------------------------------------------------------------
 
 urlDecoder :: Decoder PackageFetcher
 urlDecoder = do
   url <- getFields ["fetch", "url"]
-  pure $ \(coerce -> v) -> urlFetcher $ T.replace "$ver" v url
+  name <- getFieldsOpt ["url", "name"]
+  pure $ \(coerce -> v) -> urlFetcher' (T.replace "$ver" v url) (fmap (T.replace "$ver" v) name)
 
 --------------------------------------------------------------------------------
 
diff --git a/app/Config/VersionSource.hs b/app/Config/VersionSource.hs
--- a/app/Config/VersionSource.hs
+++ b/app/Config/VersionSource.hs
@@ -77,13 +77,13 @@
 --------------------------------------------------------------------------------
 
 gitHubReleaseDecoder :: Decoder VersionSource
-gitHubReleaseDecoder = uncurry GitHubRelease <$> getFieldWith githubDecoder "github"
+gitHubReleaseDecoder = uncurry GitHubRelease <$> getFieldWith gitHubNameDecoder "github"
 
 --------------------------------------------------------------------------------
 
 gitHubTagDecoder :: Decoder VersionSource
 gitHubTagDecoder = do
-  (_owner, _repo) <- getFieldWith githubDecoder "github_tag"
+  (_owner, _repo) <- getFieldWith gitHubNameDecoder "github_tag"
   _listOptions <- listOptionsDecoder
   pure GitHubTag {..}
 
@@ -142,12 +142,12 @@
 --------------------------------------------------------------------------------
 
 openVsxDecoder :: Decoder VersionSource
-openVsxDecoder = uncurry OpenVsx <$> getFieldWith vscodeExtensionDecoder "openvsx"
+openVsxDecoder = uncurry OpenVsx <$> getFieldWith vscodeExtensionNameDecoder "openvsx"
 
 --------------------------------------------------------------------------------
 
 vscodeMarketplaceDecoder :: Decoder VersionSource
-vscodeMarketplaceDecoder = uncurry VscodeMarketplace <$> getFieldWith vscodeExtensionDecoder "vsmarketplace"
+vscodeMarketplaceDecoder = uncurry VscodeMarketplace <$> getFieldWith vscodeExtensionNameDecoder "vsmarketplace"
 
 --------------------------------------------------------------------------------
 
diff --git a/nvfetcher.cabal b/nvfetcher.cabal
--- a/nvfetcher.cabal
+++ b/nvfetcher.cabal
@@ -1,6 +1,6 @@
 cabal-version:   2.4
 name:            nvfetcher
-version:         0.6.2.0
+version:         0.7.0.0
 synopsis:
   Generate nix sources expr for the latest version of packages
 
@@ -26,23 +26,23 @@
 
 common common-options
   build-depends:
-    , aeson                 >=1.5.6    && <2.3
+    , aeson                 >=1.5.6  && <2.3
     , aeson-pretty
-    , base                  >=4.8      && <5
+    , base                  >=4.8    && <5
     , binary
     , binary-instances      ^>=1.0
     , bytestring
     , containers
     , data-default          ^>=0.7.1
-    , extra                 ^>=1.7.9
-    , free                  ^>=5.1.5
+    , extra                 ^>=1.7
+    , free                  >=5.1    && <5.3
     , microlens
     , microlens-th
     , neat-interpolation    ^>=0.5.1
     , optparse-simple       ^>=0.1.1
     , parsec
     , prettyprinter
-    , regex-tdfa            ^>=1.3.1.1
+    , regex-tdfa            ^>=1.3.1
     , shake                 ^>=0.19
     , text
     , toml-reader           ^>=0.2
@@ -90,10 +90,7 @@
     Config.PackageFetcher
     Config.VersionSource
 
-  build-depends:
-    , nvfetcher
-    , validation-selective
-
+  build-depends:  nvfetcher
   ghc-options:    -threaded -rtsopts -with-rtsopts=-N
 
 flag build-example
diff --git a/src/NvFetcher.hs b/src/NvFetcher.hs
--- a/src/NvFetcher.hs
+++ b/src/NvFetcher.hs
@@ -51,15 +51,15 @@
   )
 where
 
-import Control.Monad.Extra (forM_, when, whenJust)
+import Control.Monad.Extra (forM_, unless, when, whenJust, whenM)
 import qualified Data.Aeson as A
 import qualified Data.Aeson.Encode.Pretty as A
 import qualified Data.Aeson.Types as A
 import qualified Data.ByteString.Lazy.Char8 as LBS
 import Data.Default
-import Data.List ((\\))
+import Data.List (partition, (\\))
 import qualified Data.Map.Strict as Map
-import Data.Maybe (catMaybes, fromMaybe)
+import Data.Maybe (catMaybes, fromJust, fromMaybe, isJust)
 import Data.Text (Text)
 import qualified Data.Text as T
 import Development.Shake
@@ -103,7 +103,7 @@
       { buildDir = optBuildDir,
         actionAfterBuild = do
           whenJust optLogPath logChangesToFile
-          when optCommit commitChanges
+          when optCommit (commitChanges (fromMaybe "Update" optCommitSummary))
           actionAfterBuild config,
         shakeConfig =
           (shakeConfig config)
@@ -113,7 +113,9 @@
             },
         filterRegex = optPkgNameFilter,
         retry = optRetry,
-        keyfile = aKeyfile
+        keyfile = aKeyfile,
+        keepOldFiles = optKeepOldFiles,
+        keepGoing = optKeepGoing
       }
 
 logChangesToFile :: FilePath -> Action ()
@@ -121,12 +123,12 @@
   changes <- getVersionChanges
   writeFile' fp $ unlines $ show <$> changes
 
-commitChanges :: Action ()
-commitChanges = do
+commitChanges :: String -> Action ()
+commitChanges commitSummary = do
   changes <- getVersionChanges
   let commitMsg = case changes of
         [x] -> Just $ show x
-        xs@(_ : _) -> Just $ "Update\n" <> unlines (show <$> xs)
+        xs@(_ : _) -> Just $ commitSummary <> "\n" <> unlines (show <$> xs)
         [] -> Nothing
   whenJust commitMsg $ \msg -> do
     putInfo "Commiting changes"
@@ -155,8 +157,8 @@
   pkgs <- Map.map pinIfUnmatch <$> runPackageSet packageSet
   lastVersions <- parseLastVersions $ buildDir </> generatedJsonFileName
   shakeDir <- getDataDir
-  -- Set shakeFiles
-  let shakeOptions1 = shakeConfig {shakeFiles = shakeDir}
+  -- Set shakeFiles and shakeVersion
+  let shakeOptions1 = shakeConfig {shakeFiles = shakeDir, shakeVersion = "2"}
   -- shakeConfig in Config will be shakeOptions1 (not including shake extra)
   shakeExtras <- initShakeExtras (config {shakeConfig = shakeOptions1}) pkgs $ fromMaybe mempty lastVersions
   -- Set shakeExtra
@@ -167,14 +169,14 @@
     -- Don't touch already pinned packages
     pinIfUnmatch x@Package {..}
       | Just regex <- filterRegex =
-        x
-          { _ppinned = case _ppinned of
-              PermanentStale -> PermanentStale
-              _ ->
-                if _pname =~ regex
-                  then NoStale
-                  else TemporaryStale
-          }
+          x
+            { _ppinned = case _ppinned of
+                PermanentStale -> PermanentStale
+                _ ->
+                  if _pname =~ regex
+                    then NoStale
+                    else TemporaryStale
+            }
       | otherwise = x
 
 --------------------------------------------------------------------------------
@@ -185,12 +187,25 @@
     getBuildDir >>= flip removeFilesAfter ["//*"]
     actionAfterClean
 
+  "purge" ~> do
+    shakeDir <- shakeFiles <$> getShakeOptions
+    removeFilesAfter shakeDir ["//*"]
+
   "build" ~> do
+    -- remove all files in build dir except generated nix and json
+    -- since core rule has always rerun, any file not generated in this run will be removed
+    unless keepOldFiles $
+      whenM (liftIO $ D.doesDirectoryExist buildDir) $ do
+        oldFiles <- (\\ [generatedJsonFileName, generatedNixFileName]) <$> liftIO (D.listDirectory buildDir)
+        putVerbose $ "Removing old files: " <> show oldFiles
+        liftIO $ removeFiles buildDir oldFiles
     allKeys <- getAllPackageKeys
-    results <- parallel $ runPackage <$> allKeys
+    results <- fmap (zip allKeys) $ parallel $ runPackage <$> allKeys
+    let (fmap (fromJust . snd) -> successResults, fmap fst -> failureKeys) = partition (isJust . snd) results
     -- Record removed packages to version changes
+    -- Failure keys are also considered as removed in this run
     getAllOnDiskVersions
-      >>= \oldPkgs -> forM_ (Map.keys oldPkgs \\ allKeys) $
+      >>= \oldPkgs -> forM_ (Map.keys oldPkgs \\ (allKeys \\ failureKeys)) $
         \pkg -> recordVersionChange (coerce pkg) (oldPkgs Map.!? pkg) "∅"
     getVersionChanges >>= \changes ->
       if null changes
@@ -202,9 +217,9 @@
     let generatedNixPath = buildDir </> generatedNixFileName
         generatedJSONPath = buildDir </> generatedJsonFileName
     putVerbose $ "Generating " <> generatedNixPath
-    writeFileChanged generatedNixPath $ T.unpack $ srouces (T.unlines $ toNixExpr <$> results) <> "\n"
+    writeFileChanged generatedNixPath $ T.unpack $ srouces (T.unlines $ toNixExpr <$> successResults) <> "\n"
     putVerbose $ "Generating " <> generatedJSONPath
-    writeFileChanged generatedJSONPath $ LBS.unpack $ A.encodePretty $ A.object [aesonKey (_prname r) A..= r | r <- results]
+    writeFileChanged generatedJSONPath $ LBS.unpack $ A.encodePretty $ A.object [aesonKey (_prname r) A..= r | r <- successResults]
     actionAfterBuild
 
   customRules
diff --git a/src/NvFetcher/Config.hs b/src/NvFetcher/Config.hs
--- a/src/NvFetcher/Config.hs
+++ b/src/NvFetcher/Config.hs
@@ -18,8 +18,11 @@
     retry :: Int,
     filterRegex :: Maybe String,
     cacheNvchecker :: Bool,
+    keepOldFiles :: Bool,
     -- | Absolute path
-    keyfile :: Maybe FilePath
+    keyfile :: Maybe FilePath,
+    -- | When set to 'True', nvfetcher will keep going even if some packages failed to /fetch/
+    keepGoing :: Bool
   }
 
 instance Default Config where
@@ -37,5 +40,7 @@
         retry = 3,
         filterRegex = Nothing,
         cacheNvchecker = True,
-        keyfile = Nothing
+        keepOldFiles = False,
+        keyfile = Nothing,
+        keepGoing = False
       }
diff --git a/src/NvFetcher/Core.hs b/src/NvFetcher/Core.hs
--- a/src/NvFetcher/Core.hs
+++ b/src/NvFetcher/Core.hs
@@ -43,7 +43,7 @@
     -- since the package definition is not tracked at all
     alwaysRerun
     lookupPackage pkg >>= \case
-      Nothing -> fail $ "Unkown package key: " <> show pkg
+      Nothing -> fail $ "Unknown package key: " <> show pkg
       Just
         Package
           { _pversion = CheckVersion versionSource options,
@@ -52,71 +52,75 @@
           } -> do
           _prversion@(NvcheckerResult version _mOldV _isStale) <- checkVersion versionSource options pkg
           _prfetched <- prefetch (_pfetcher version) _pforcefetch
-          buildDir <- getBuildDir
-          -- extract src
-          _prextract <-
-            case _pextract of
-              Just (PackageExtractSrc extract) -> do
-                result <- HMap.toList <$> extractSrcs _prfetched extract
-                Just . HMap.fromList
-                  <$> sequence
-                    [ do
-                        -- write extracted files to build dir
-                        -- and read them in nix using 'builtins.readFile'
-                        writeFile' (buildDir </> path) (T.unpack v)
-                        pure (k, T.pack path)
-                      | (k, v) <- result,
-                        let path =
-                              "./"
-                                <> T.unpack _pname
+          -- If we fail to prefetch, we should fail on this package
+          case _prfetched of
+            Just _prfetched -> do
+              buildDir <- getBuildDir
+              -- extract src
+              _prextract <-
+                case _pextract of
+                  Just (PackageExtractSrc extract) -> do
+                    result <- HMap.toList <$> extractSrcs _prfetched extract
+                    Just . HMap.fromList
+                      <$> sequence
+                        [ do
+                            -- write extracted files to build dir
+                            -- and read them in nix using 'builtins.readFile'
+                            writeFile' (buildDir </> path) (T.unpack v)
+                            pure (k, T.pack path)
+                          | (k, v) <- result,
+                            let path =
+                                  "./"
+                                    <> T.unpack _pname
+                                    <> "-"
+                                    <> T.unpack (coerce version)
+                                    </> k
+                        ]
+                  _ -> pure Nothing
+              -- cargo locks
+              _prcargolock <-
+                case _pcargo of
+                  Just (PackageCargoLockFiles lockPath) -> do
+                    lockFiles <- HMap.toList <$> extractSrcs _prfetched lockPath
+                    result <- parallel $
+                      flip fmap lockFiles $ \(lockPath, lockData) -> do
+                        result <- fetchRustGitDeps _prfetched lockPath
+                        let lockPath' =
+                              T.unpack _pname
                                 <> "-"
                                 <> T.unpack (coerce version)
-                                </> k
-                    ]
-              _ -> pure Nothing
-          -- cargo locks
-          _prcargolock <-
-            case _pcargo of
-              Just (PackageCargoLockFiles lockPath) -> do
-                lockFiles <- HMap.toList <$> extractSrcs _prfetched lockPath
-                result <- parallel $
-                  flip fmap lockFiles $ \(lockPath, lockData) -> do
-                    result <- fetchRustGitDeps _prfetched lockPath
-                    let lockPath' =
-                          T.unpack _pname
-                            <> "-"
-                            <> T.unpack (coerce version)
-                            </> lockPath
-                        lockPathNix = "./" <> T.pack lockPath'
-                    -- similar to extract src, write lock file to build dir
-                    writeFile' (buildDir </> lockPath') $ T.unpack lockData
-                    pure (lockPath, (lockPathNix, result))
-                pure . Just $ HMap.fromList result
-              _ -> pure Nothing
+                                </> lockPath
+                            lockPathNix = "./" <> T.pack lockPath'
+                        -- similar to extract src, write lock file to build dir
+                        writeFile' (buildDir </> lockPath') $ T.unpack lockData
+                        pure (lockPath, (lockPathNix, result))
+                    pure . Just $ HMap.fromList result
+                  _ -> pure Nothing
 
-          -- Only git version source supports git commit date
-          _prgitdate <- case versionSource of
-            Git {..} -> Just <$> getGitCommitDate _vurl (coerce version) _pgitdateformat
-            _ -> pure Nothing
+              -- Only git version source supports git commit date
+              _prgitdate <- case versionSource of
+                Git {..} -> Just <$> getGitCommitDate _vurl (coerce version) _pgitdateformat
+                _ -> pure Nothing
 
-          -- update changelog
-          -- always use on disk version
-          mOldV <- getLastVersionOnDisk pkg
-          case mOldV of
-            Nothing ->
-              recordVersionChange _pname Nothing version
-            Just old
-              | old /= version ->
-                recordVersionChange _pname (Just old) version
-            _ -> pure ()
+              -- update changelog
+              -- always use on disk version
+              mOldV <- getLastVersionOnDisk pkg
+              case mOldV of
+                Nothing ->
+                  recordVersionChange _pname Nothing version
+                Just old
+                  | old /= version ->
+                      recordVersionChange _pname (Just old) version
+                _ -> pure ()
 
-          let _prpassthru = if HMap.null passthru then Nothing else Just passthru
-              _prname = _pname
-              _prpinned = _ppinned
-          -- Since we don't save the previous result, we are not able to know if the result changes
-          -- Depending on this rule leads to RunDependenciesChanged
-          pure $ RunResult ChangedRecomputeDiff mempty PackageResult {..}
+              let _prpassthru = if HMap.null passthru then Nothing else Just passthru
+                  _prname = _pname
+                  _prpinned = _ppinned
+              -- Since we don't save the previous result, we are not able to know if the result changes
+              -- Depending on this rule leads to RunDependenciesChanged
+              pure $ RunResult ChangedRecomputeDiff mempty $ Just PackageResult {..}
+            _ -> pure $ RunResult ChangedRecomputeDiff mempty Nothing
 
 -- | 'Core' rule take a 'PackageKey', find the corresponding 'Package', and run all needed rules to get 'PackageResult'
-runPackage :: PackageKey -> Action PackageResult
+runPackage :: PackageKey -> Action (Maybe PackageResult)
 runPackage k = apply1 $ WithPackageKey (Core, k)
diff --git a/src/NvFetcher/FetchRustGitDeps.hs b/src/NvFetcher/FetchRustGitDeps.hs
--- a/src/NvFetcher/FetchRustGitDeps.hs
+++ b/src/NvFetcher/FetchRustGitDeps.hs
@@ -24,6 +24,7 @@
 where
 
 import Control.Monad (void)
+import Control.Monad.Extra (fromMaybeM)
 import Data.Binary.Instances ()
 import Data.Coerce (coerce)
 import Data.HashMap.Strict (HashMap)
@@ -54,7 +55,7 @@
       parallel
         [ case parse gitSrcParser (T.unpack rname) src of
             Right ParsedGitSrc {..} -> do
-              (_sha256 -> sha256) <- prefetch (gitFetcher pgurl pgsha) NoForceFetch
+              (_sha256 -> sha256) <- fromMaybeM (fail $ "Prefetch failed for " <> T.unpack pgurl) $ prefetch (gitFetcher pgurl pgsha) NoForceFetch
               -- @${name}-${version}@ -> sha256
               pure (rname <> "-" <> coerce rversion, sha256)
             Left err -> fail $ "Failed to parse git source in Cargo.lock: " <> show err
diff --git a/src/NvFetcher/NixExpr.hs b/src/NvFetcher/NixExpr.hs
--- a/src/NvFetcher/NixExpr.hs
+++ b/src/NvFetcher/NixExpr.hs
@@ -67,6 +67,7 @@
       _fetchSubmodules = toNixExpr -> fetchSubmodules,
       _deepClone = toNixExpr -> deepClone,
       _leaveDotGit = toNixExpr -> leaveDotGit,
+      _sparseCheckout = toNixExpr . map quote -> sparseCheckout,
       _furl = quote -> url,
       _name = nameField -> n
     } ->
@@ -76,7 +77,8 @@
             rev = $rev;
             fetchSubmodules = $fetchSubmodules;
             deepClone = $deepClone;
-            leaveDotGit = $leaveDotGit;$n
+            leaveDotGit = $leaveDotGit;
+            sparseCheckout = $sparseCheckout;$n
             sha256 = $sha256;
           }
     |]
@@ -86,13 +88,14 @@
       _fetchSubmodules = toNixExpr -> fetchSubmodules,
       _deepClone = toNixExpr -> deepClone,
       _leaveDotGit = toNixExpr -> leaveDotGit,
+      _sparseCheckout = toNixExpr . map quote -> sparseCheckout,
       _fowner = quote -> owner,
       _frepo = quote -> repo,
       _name = nameField -> n
     } ->
-      -- TODO: fix fetchFromGitHub in Nixpkgs so that deepClone and
-      -- leaveDotGit won't get passed to fetchzip
-      if (deepClone == "true") || (leaveDotGit == "true")
+      -- TODO: fix fetchFromGitHub in Nixpkgs so that deepClone, leaveDotGit
+      -- and sparseCheckout won't get passed to fetchzip
+      if (deepClone == "true") || (leaveDotGit == "true") || (sparseCheckout /= "[ ]")
         then
           [trimming|
                fetchFromGitHub {
@@ -101,7 +104,8 @@
                  rev = $rev;
                  fetchSubmodules = $fetchSubmodules;
                  deepClone = $deepClone;
-                 leaveDotGit = $leaveDotGit;$n
+                 leaveDotGit = $leaveDotGit;
+                 sparseCheckout = $sparseCheckout;$n
                  sha256 = $sha256;
                }
          |]
diff --git a/src/NvFetcher/NixFetcher.hs b/src/NvFetcher/NixFetcher.hs
--- a/src/NvFetcher/NixFetcher.hs
+++ b/src/NvFetcher/NixFetcher.hs
@@ -48,12 +48,14 @@
     gitHubReleaseFetcher',
     gitFetcher,
     urlFetcher,
+    urlFetcher',
     openVsxFetcher,
     vscodeMarketplaceFetcher,
     tarballFetcher,
   )
 where
 
+import Control.Exception (ErrorCall)
 import Control.Monad (void, when)
 import qualified Data.Aeson as A
 import Data.Coerce (coerce)
@@ -79,12 +81,14 @@
     [x] -> pure $ coerce x
     _ -> fail $ "Failed to parse output from nix hash to-sri: " <> T.unpack out
 
-runNixPrefetchUrl :: Text -> Bool -> Action Checksum
-runNixPrefetchUrl url unpack = do
+runNixPrefetchUrl :: Text -> Bool -> Maybe Text -> Action Checksum
+runNixPrefetchUrl url unpack name = do
   (CmdTime t, Stdout (T.decodeUtf8 -> out), CmdLine c) <-
     quietly $
       command [EchoStderr False] "nix-prefetch-url" $
-        [T.unpack url] <> ["--unpack" | unpack]
+        [T.unpack url]
+          <> ["--unpack" | unpack]
+          <> concat [["--name", T.unpack name] | Just name <- [name]]
   putVerbose $ "Finishing running " <> c <> ", took " <> show t <> "s"
   case takeWhile (not . T.null) $ reverse $ T.lines out of
     [x] -> sha256ToSri x
@@ -93,8 +97,8 @@
 newtype FetchedGit = FetchedGit {sha256 :: Text}
   deriving (Show, Generic, A.FromJSON)
 
-runNixPrefetchGit :: Text -> Text -> Bool -> Bool -> Bool -> Action Checksum
-runNixPrefetchGit url rev fetchSubmodules deepClone leaveDotGit = do
+runNixPrefetchGit :: Text -> Text -> Bool -> Bool -> Bool -> [Text] -> Action Checksum
+runNixPrefetchGit url rev fetchSubmodules deepClone leaveDotGit sparseCheckout = do
   (CmdTime t, Stdout out, CmdLine c) <-
     quietly $
       command [EchoStderr False] "nix-prefetch-git" $
@@ -103,6 +107,7 @@
           <> ["--fetch-submodules" | fetchSubmodules]
           <> ["--deepClone" | deepClone]
           <> ["--leave-dotGit" | leaveDotGit]
+          <> if null sparseCheckout then [] else ["--sparse-checkout", T.unpack $ T.intercalate "\n" sparseCheckout]
   putVerbose $ "Finishing running " <> c <> ", took " <> show t <> "s"
   case A.eitherDecode out of
     Right (FetchedGit x) -> sha256ToSri x
@@ -113,21 +118,21 @@
 runFetcher :: NixFetcher Fresh -> Action (NixFetcher Fetched)
 runFetcher = \case
   FetchGit {..} -> do
-    result <- runNixPrefetchGit _furl (coerce _rev) _fetchSubmodules _deepClone _leaveDotGit
+    result <- runNixPrefetchGit _furl (coerce _rev) _fetchSubmodules _deepClone _leaveDotGit _sparseCheckout
     pure FetchGit {_sha256 = coerce result, ..}
   FetchGitHub {..} -> do
-    let useFetchGit = _fetchSubmodules || _leaveDotGit || _deepClone
+    let useFetchGit = _fetchSubmodules || _leaveDotGit || _deepClone || not (null _sparseCheckout)
         ver = coerce _rev
     result <-
       if useFetchGit
-        then runNixPrefetchGit [trimming|https://github.com/$_fowner/$_frepo|] (coerce _rev) _fetchSubmodules _deepClone _leaveDotGit
-        else runNixPrefetchUrl [trimming|https://github.com/$_fowner/$_frepo/archive/$ver.tar.gz|] True
+        then runNixPrefetchGit [trimming|https://github.com/$_fowner/$_frepo|] (coerce _rev) _fetchSubmodules _deepClone _leaveDotGit _sparseCheckout
+        else runNixPrefetchUrl [trimming|https://github.com/$_fowner/$_frepo/archive/$ver.tar.gz|] True mempty
     pure FetchGitHub {_sha256 = result, ..}
   FetchUrl {..} -> do
-    result <- runNixPrefetchUrl _furl False
+    result <- runNixPrefetchUrl _furl False _name
     pure FetchUrl {_sha256 = result, ..}
   FetchTarball {..} -> do
-    result <- runNixPrefetchUrl _furl True
+    result <- runNixPrefetchUrl _furl True mempty
     pure FetchTarball {_sha256 = result, ..}
   FetchDocker {..} -> do
     (CmdTime t, Stdout out, CmdLine c) <-
@@ -165,24 +170,31 @@
   addOracleCache $ \(RunFetch force f) -> do
     when (force == ForceFetch) alwaysRerun
     putInfo . show $ "#" <+> pretty f
-    withRetry $ runFetcher f
+    keepGoing <- nvcheckerKeepGoing
+    if keepGoing
+      then -- If fetch failed, always rerun and return Nothing
+      actionCatch (fmap Just <$> withRetry $ runFetcher f) $ \(e :: ErrorCall) -> do
+        alwaysRerun
+        putError $ show e <> "\nKeep going..."
+        pure Nothing
+      else fmap Just <$> withRetry $ runFetcher f
 
 -- | Run nix fetcher
-prefetch :: NixFetcher Fresh -> ForceFetch -> Action (NixFetcher Fetched)
+prefetch :: NixFetcher Fresh -> ForceFetch -> Action (Maybe (NixFetcher Fetched))
 prefetch f force = askOracle $ RunFetch force f
 
 --------------------------------------------------------------------------------
 
 -- | Create a fetcher from git url
 gitFetcher :: Text -> PackageFetcher
-gitFetcher furl rev = FetchGit furl rev False True False Nothing ()
+gitFetcher furl rev = FetchGit furl rev False True False [] Nothing ()
 
 -- | Create a fetcher from github repo
 gitHubFetcher ::
   -- | owner and repo
   (Text, Text) ->
   PackageFetcher
-gitHubFetcher (owner, repo) rev = FetchGitHub owner repo rev False False False Nothing ()
+gitHubFetcher (owner, repo) rev = FetchGitHub owner repo rev False False False [] Nothing ()
 
 -- | Create a fetcher from pypi
 pypiFetcher :: Text -> PackageFetcher
@@ -212,6 +224,10 @@
 -- | Create a fetcher from url
 urlFetcher :: Text -> NixFetcher Fresh
 urlFetcher url = FetchUrl url Nothing ()
+
+-- | Create a fetcher from url specifying the file name
+urlFetcher' :: Text -> Maybe Text -> NixFetcher Fresh
+urlFetcher' url name = FetchUrl url name ()
 
 -- | Create a fetcher from openvsx
 openVsxFetcher ::
diff --git a/src/NvFetcher/Nvchecker.hs b/src/NvFetcher/Nvchecker.hs
--- a/src/NvFetcher/Nvchecker.hs
+++ b/src/NvFetcher/Nvchecker.hs
@@ -131,10 +131,10 @@
           genOptions options
       )
   where
-    key =: x = tell [key <> " = " <> T.pack (show $ T.unpack x)]
+    key =: x = tell [key <> " = " <> quote x]
     key =:? (Just x) = key =: x
     _ =:? _ = pure ()
-    table t m = tell ["[" <> t <> "]"] >> m >> tell [""]
+    table t m = tell ["[" <> quote t <> "]"] >> m >> tell [""]
     genVersionSource = \case
       GitHubRelease {..} -> do
         "source" =: "github"
diff --git a/src/NvFetcher/Options.hs b/src/NvFetcher/Options.hs
--- a/src/NvFetcher/Options.hs
+++ b/src/NvFetcher/Options.hs
@@ -19,23 +19,26 @@
 import Options.Applicative.Simple
 import qualified Paths_nvfetcher as Paths
 
-data Target = Build | Clean
+data Target = Build | Clean | Purge
   deriving (Eq)
 
 instance Show Target where
   show Build = "build"
   show Clean = "clean"
+  show Purge = "purge"
 
 targetParser :: ReadM Target
 targetParser = maybeReader $ \case
   "build" -> Just Build
   "clean" -> Just Clean
+  "purge" -> Just Purge
   _ -> Nothing
 
 -- | Options for nvfetcher CLI
 data CLIOptions = CLIOptions
   { optBuildDir :: FilePath,
     optCommit :: Bool,
+    optCommitSummary :: Maybe String,
     optLogPath :: Maybe FilePath,
     optThreads :: Int,
     optRetry :: Int,
@@ -43,6 +46,8 @@
     optVerbose :: Bool,
     optPkgNameFilter :: Maybe String,
     optKeyfile :: Maybe FilePath,
+    optKeepOldFiles :: Bool,
+    optKeepGoing :: Bool,
     optTarget :: Target
   }
   deriving (Show)
@@ -65,6 +70,13 @@
       )
     <*> optional
       ( strOption
+          ( long "commit-summary"
+              <> metavar "SUMMARY"
+              <> help "Summary to use when committing changes"
+          )
+      )
+    <*> optional
+      ( strOption
           ( long "changelog"
               <> short 'l'
               <> metavar "FILE"
@@ -108,12 +120,14 @@
               <> completer (bashCompleter "file")
           )
       )
+    <*> switch (long "keep-old" <> help "Don't remove old files other than generated json and nix before build")
+    <*> switch (long "keep-going" <> help "Don't stop if some packages failed to be fetched")
     <*> argument
       targetParser
       ( metavar "TARGET"
-          <> help "Two targets are available: 1.build  2.clean"
+          <> help "Three targets are available: 1.build  2.clean (remove all generated files) 3.purge (remove shake db)"
           <> value Build
-          <> completer (listCompleter [show Build, show Clean])
+          <> completer (listCompleter [show Build, show Clean, show Purge])
           <> showDefault
       )
 
diff --git a/src/NvFetcher/PackageSet.hs b/src/NvFetcher/PackageSet.hs
--- a/src/NvFetcher/PackageSet.hs
+++ b/src/NvFetcher/PackageSet.hs
@@ -75,6 +75,7 @@
     fetchGit,
     fetchGit',
     fetchUrl,
+    fetchUrl',
     fetchOpenVsx,
     fetchVscodeMarketplace,
     fetchTarball,
@@ -194,23 +195,23 @@
 class Member (a :: Type) (r :: [Type]) where
   proj :: Prod r -> a
 
-instance {-# OVERLAPPING #-} NotElem x xs => Member x (x ': xs) where
+instance {-# OVERLAPPING #-} (NotElem x xs) => Member x (x ': xs) where
   proj (Cons x _) = x
 
-instance Member x xs => Member x (_y ': xs) where
+instance (Member x xs) => Member x (_y ': xs) where
   proj (Cons _ r) = proj r
 
-instance TypeError (ShowType x :<>: 'Text " is undefined") => Member x '[] where
+instance (TypeError (ShowType x :<>: 'Text " is undefined")) => Member x '[] where
   proj = undefined
 
 -- | Project optional elements from 'Prod'
 class OptionalMember (a :: Type) (r :: [Type]) where
   projMaybe :: Prod r -> Maybe a
 
-instance {-# OVERLAPPING #-} NotElem x xs => OptionalMember x (x ': xs) where
+instance {-# OVERLAPPING #-} (NotElem x xs) => OptionalMember x (x ': xs) where
   projMaybe (Cons x _) = Just x
 
-instance OptionalMember x xs => OptionalMember x (_y ': xs) where
+instance (OptionalMember x xs) => OptionalMember x (_y ': xs) where
   projMaybe (Cons _ r) = projMaybe r
 
 instance OptionalMember x '[] where
@@ -514,6 +515,12 @@
 -- Arg is a function which constructs the url from a version
 fetchUrl :: Attach PackageFetcher (Version -> Text)
 fetchUrl e f = fetch e (urlFetcher . f)
+
+-- | This package is fetched from url
+--
+-- Args are a function which constructs the url from a version and a file name
+fetchUrl' :: Attach PackageFetcher (Text, Version -> Text)
+fetchUrl' e (name, f) = fetch e (\v -> FetchUrl (f v) (Just name) ())
 
 -- | This package is fetched from Open VSX
 --
diff --git a/src/NvFetcher/Types.hs b/src/NvFetcher/Types.hs
--- a/src/NvFetcher/Types.hs
+++ b/src/NvFetcher/Types.hs
@@ -383,7 +383,8 @@
 data RunFetch = RunFetch ForceFetch (NixFetcher Fresh)
   deriving (Show, Eq, Ord, Hashable, NFData, Binary, Typeable, Generic)
 
-type instance RuleResult RunFetch = NixFetcher Fetched
+-- Prefetch rule never throws exceptions
+type instance RuleResult RunFetch = Maybe (NixFetcher Fetched)
 
 -- | If the package is prefetched, then we can obtain the SHA256
 data NixFetcher (k :: FetchStatus)
@@ -393,6 +394,7 @@
         _deepClone :: Bool,
         _fetchSubmodules :: Bool,
         _leaveDotGit :: Bool,
+        _sparseCheckout :: [Text],
         _name :: Maybe Text,
         _sha256 :: FetchResult Checksum k
       }
@@ -403,6 +405,7 @@
         _deepClone :: Bool,
         _fetchSubmodules :: Bool,
         _leaveDotGit :: Bool,
+        _sparseCheckout :: [Text],
         _name :: Maybe Text,
         _sha256 :: FetchResult Checksum k
       }
@@ -460,6 +463,7 @@
         "deepClone" A..= _deepClone,
         "fetchSubmodules" A..= _fetchSubmodules,
         "leaveDotGit" A..= _leaveDotGit,
+        "sparseCheckout" A..= _sparseCheckout,
         "name" A..= _name,
         "sha256" A..= _sha256,
         "type" A..= A.String "git"
@@ -472,6 +476,7 @@
         "deepClone" A..= _deepClone,
         "fetchSubmodules" A..= _fetchSubmodules,
         "leaveDotGit" A..= _leaveDotGit,
+        "sparseCheckout" A..= _sparseCheckout,
         "name" A..= _name,
         "sha256" A..= _sha256,
         "type" A..= A.String "github"
@@ -513,7 +518,8 @@
               "rev" <> colon <+> pretty _rev,
               "deepClone" <> colon <+> pretty _deepClone,
               "fetchSubmodules" <> colon <+> pretty _fetchSubmodules,
-              "leaveDotGit" <> colon <+> pretty _leaveDotGit
+              "leaveDotGit" <> colon <+> pretty _leaveDotGit,
+              "sparseCheckout" <> colon <+> pretty _sparseCheckout
             ]
               <> ppField "name" _name
         )
@@ -528,7 +534,8 @@
               "rev" <> colon <+> pretty _rev,
               "deepClone" <> colon <+> pretty _deepClone,
               "fetchSubmodules" <> colon <+> pretty _fetchSubmodules,
-              "leaveDotGit" <> colon <+> pretty _leaveDotGit
+              "leaveDotGit" <> colon <+> pretty _leaveDotGit,
+              "sparseCheckout" <> colon <+> pretty _sparseCheckout
             ]
               <> ppField "name" _name
         )
@@ -702,7 +709,8 @@
 data Core = Core
   deriving (Eq, Show, Ord, Typeable, Generic, Hashable, Binary, NFData)
 
-type instance RuleResult Core = PackageResult
+-- If prefetch fails, we don't want to fail the whole build
+type instance RuleResult Core = Maybe PackageResult
 
 -- | Decorate a rule's key with 'PackageKey'
 newtype WithPackageKey k = WithPackageKey (k, PackageKey)
diff --git a/src/NvFetcher/Types/ShakeExtras.hs b/src/NvFetcher/Types/ShakeExtras.hs
--- a/src/NvFetcher/Types/ShakeExtras.hs
+++ b/src/NvFetcher/Types/ShakeExtras.hs
@@ -40,8 +40,9 @@
     getAllOnDiskVersions,
     getLastVersionUpdated,
 
-    -- * Cache nvchecker
+    -- * Booleans
     nvcheckerCacheEnabled,
+    nvcheckerKeepGoing,
   )
 where
 
@@ -175,3 +176,7 @@
 -- | Get if 'cacheNvchecker' is enabled
 nvcheckerCacheEnabled :: Action Bool
 nvcheckerCacheEnabled = cacheNvchecker . config <$> getShakeExtras
+
+-- | Get if 'keepGoing' is enabled
+nvcheckerKeepGoing :: Action Bool
+nvcheckerKeepGoing = keepGoing . config <$> getShakeExtras
diff --git a/test/FetchRustGitDepsSpec.hs b/test/FetchRustGitDepsSpec.hs
--- a/test/FetchRustGitDepsSpec.hs
+++ b/test/FetchRustGitDepsSpec.hs
@@ -3,6 +3,7 @@
 
 module FetchRustGitDepsSpec where
 
+import Control.Monad (join)
 import Control.Monad.Trans.Reader
 import Data.HashMap.Strict (HashMap)
 import qualified Data.HashMap.Strict as HMap
@@ -30,7 +31,7 @@
           ]
 
 runPrefetchRule :: NixFetcher Fresh -> ReaderT ActionQueue IO (Maybe (NixFetcher Fetched))
-runPrefetchRule fetcher = runActionChan $ prefetch fetcher NoForceFetch
+runPrefetchRule fetcher = fmap join $ runActionChan $ prefetch fetcher NoForceFetch
 
 runFetchRustGitDepsRule :: NixFetcher Fetched -> FilePath -> ReaderT ActionQueue IO (Maybe (HashMap Text Checksum))
 runFetchRustGitDepsRule fetcher lockPath = runActionChan $ fetchRustGitDeps fetcher lockPath
diff --git a/test/NixExprSpec.hs b/test/NixExprSpec.hs
--- a/test/NixExprSpec.hs
+++ b/test/NixExprSpec.hs
@@ -34,6 +34,7 @@
         fetchSubmodules = true;
         deepClone = false;
         leaveDotGit = false;
+        sparseCheckout = [ ];
         sha256 = "0000000000000000000000000000000000000000000000000000000000000000";
       }
     |]
diff --git a/test/PrefetchSpec.hs b/test/PrefetchSpec.hs
--- a/test/PrefetchSpec.hs
+++ b/test/PrefetchSpec.hs
@@ -4,6 +4,7 @@
 module PrefetchSpec where
 
 import Control.Arrow ((&&&))
+import Control.Monad (join)
 import Control.Monad.Trans.Reader
 import NvFetcher.NixFetcher
 import NvFetcher.Types
@@ -39,11 +40,18 @@
 
     specifyChan "docker" $
       runPrefetchRule' (_sha256 &&& _imageDigest) testDockerFetcher
-        `shouldReturnJust`
-          ( Checksum "sha256-uaJxeiRm94tWDBTe51/KwUBKR2vj9i4i3rhotsYPxtM=",
-            ContainerDigest "sha256:65a2763f593ae85fab3b5406dc9e80f744ec5b449f269b699b5efd37a07ad32e"
-          )
+        `shouldReturnJust` ( Checksum "sha256-uaJxeiRm94tWDBTe51/KwUBKR2vj9i4i3rhotsYPxtM=",
+                             ContainerDigest "sha256:65a2763f593ae85fab3b5406dc9e80f744ec5b449f269b699b5efd37a07ad32e"
+                           )
 
+    specifyChan "url with name" $
+      runPrefetchRule
+        ( urlFetcher'
+            "https://files.yande.re/image/3fc51f6a2fb10c96b73dd0fce6ddb9c8/yande.re%201048717%20dress%20garter%20lolita_fashion%20ruo_gan_zhua.jpg"
+            (Just "foo.jpg")
+        )
+        `shouldReturnJust` Checksum "sha256-wkiXDN6vPFtx88krcQ4szK6dJNjtrDxrsNa3ZvHlfMQ="
+
 testDockerFetcher :: NixFetcher Fresh
 testDockerFetcher =
   FetchDocker
@@ -65,4 +73,4 @@
 runPrefetchRule = runPrefetchRule' _sha256
 
 runPrefetchRule' :: (NixFetcher Fetched -> a) -> NixFetcher Fresh -> ReaderT ActionQueue IO (Maybe a)
-runPrefetchRule' g f = runActionChan $ g <$> prefetch f NoForceFetch
+runPrefetchRule' g f = fmap join $ runActionChan $ prefetch f NoForceFetch >>= \m -> pure $ g <$> m