Enhance API client error messages

dandi/dandiapi.py

@@ -447,7 +447,11 @@ def __init__(
                 dandi_instance = get_instance(instance_name)
             api_url = dandi_instance.api
         elif dandi_instance is not None:
-            raise ValueError("api_url and dandi_instance are mutually exclusive")
+            raise ValueError(
+                "api_url and dandi_instance are mutually exclusive. "
+                "Use either 'api_url' to specify a custom API URL, "
+                "or 'dandi_instance' to use a registered DANDI instance, but not both."
+            )
         else:
             dandi_instance = get_instance(api_url)
         super().__init__(api_url)
@@ -574,7 +578,10 @@ def get_dandiset(
                     self, self.get(f"/dandisets/{dandiset_id}/")
                 )
             except HTTP404Error:
-                raise NotFoundError(f"No such Dandiset: {dandiset_id!r}")
+                raise NotFoundError(
+                    f"No such Dandiset: {dandiset_id!r}. "
+                    "Verify the Dandiset ID is correct and that you have access. "
+                )
             if version_id is not None and version_id != d.version_id:
                 if version_id == DRAFT:
                     return d.for_version(d.draft_version)
@@ -744,7 +751,11 @@ def get_asset(self, asset_id: str) -> BaseRemoteAsset:
         try:
             info = self.get(f"/assets/{asset_id}/info/")
         except HTTP404Error:
-            raise NotFoundError(f"No such asset: {asset_id!r}")
+            raise NotFoundError(
+                f"No such asset: {asset_id!r}. "
+                "Verify the asset ID is correct. "
+                "Use 'dandi ls' to list available assets."
+            )
         metadata = info.pop("metadata", None)
         return BaseRemoteAsset.from_base_data(self, info, metadata)
 
@@ -1318,7 +1329,11 @@ def get_asset_by_path(self, path: str) -> RemoteAsset:
                 a for a in self.get_assets_with_path_prefix(path) if a.path == path
             )
         except ValueError:
-            raise NotFoundError(f"No asset at path {path!r}")
+            raise NotFoundError(
+                f"No asset at path {path!r} in version {self.version_id}. "
+                "Verify the path is correct and the asset exists in this version. "
+                "Use 'dandi ls' to list available assets."
+            )
         else:
             return asset
 

dandi/tests/test_dandiarchive.py

@@ -588,11 +588,17 @@ def test_get_nonexistent_dandiset(
     parsed_url.get_dandiset(client)  # No error
     with pytest.raises(NotFoundError) as excinfo:
         parsed_url.get_dandiset(client, lazy=False)
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
 
 
 @pytest.mark.parametrize("version", ["draft", "0.999999.9999"])
@@ -608,7 +614,10 @@ def test_get_nonexistent_dandiset_asset_id(
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
 
 
 def test_get_dandiset_nonexistent_asset_id(text_dandiset: SampleDandiset) -> None:
@@ -635,7 +644,11 @@ def test_get_nonexistent_asset_id(local_dandi_api: DandiAPI) -> None:
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such asset: '00000000-0000-0000-0000-000000000000'"
+    assert str(excinfo.value) == (
+        "No such asset: '00000000-0000-0000-0000-000000000000'. "
+        "Verify the asset ID is correct. "
+        "Use 'dandi ls' to list available assets."
+    )
 
 
 @pytest.mark.parametrize("version_suffix", ["", "@draft", "@0.999999.9999"])
@@ -648,7 +661,10 @@ def test_get_nonexistent_dandiset_asset_path(
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
 
 
 def test_get_nonexistent_asset_path(text_dandiset: SampleDandiset) -> None:
@@ -661,7 +677,11 @@ def test_get_nonexistent_asset_path(text_dandiset: SampleDandiset) -> None:
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No asset at path 'does/not/exist'"
+    assert str(excinfo.value) == (
+        "No asset at path 'does/not/exist' in version draft. "
+        "Verify the path is correct and the asset exists in this version. "
+        "Use 'dandi ls' to list available assets."
+    )
 
 
 @pytest.mark.parametrize("version_suffix", ["", "@draft", "@0.999999.9999"])
@@ -677,7 +697,10 @@ def test_get_nonexistent_dandiset_asset_folder(
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
 
 
 def test_get_nonexistent_asset_folder(text_dandiset: SampleDandiset) -> None:
@@ -706,7 +729,10 @@ def test_get_nonexistent_dandiset_asset_prefix(
     assert list(parsed_url.get_assets(client)) == []
     with pytest.raises(NotFoundError) as excinfo:
         next(parsed_url.get_assets(client, strict=True))
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
 
 
 def test_get_nonexistent_asset_prefix(text_dandiset: SampleDandiset) -> None:

dandi/tests/test_delete.py

@@ -252,7 +252,10 @@ def test_delete_nonexistent_dandiset(
             devel_debug=True,
             force=True,
         )
-    assert str(excinfo.value) == "No such Dandiset: '999999'"
+    assert str(excinfo.value) == (
+        "No such Dandiset: '999999'. "
+        "Verify the Dandiset ID is correct and that you have access. "
+    )
     delete_spy.assert_not_called()