Add support for passing options to vega CLI utils via `vega_cli_optio…

…ns` kwarg (#52)

altair_saver/_core.py

@@ -118,6 +118,9 @@ def save(
     vegaembed_version : string (optional)
         For method in {"selenium", "html"}, the version of the vega-embed javascript
         package to use. Default is alt.VEGAEMBED_VERSION.
+    vega_cli_options : list (optional)
+        For method="node", a list of additional arguments to pass to vega's CLI functions.
+        All options will be passed to all Vega commands (e.g., `vg2svg`, `vg2pdf`, etc.).
     inline : boolean (optional)
         For method="html", specify whether javascript sources should be included
         inline rather than loaded from an external CDN. Default: False.
@@ -209,6 +212,9 @@ def render(
     vegaembed_version : string (optional)
         For method in {"selenium", "html"}, the version of the vega-embed javascript
         package to use. Default is alt.VEGAEMBED_VERSION.
+    vega_cli_options : list (optional)
+        For method="node", a list of additional arguments to pass to vega's CLI functions.
+        All options will be passed to all Vega commands (e.g., `vg2svg`, `vg2pdf`, etc.).
     inline : boolean (optional)
         For method="html", specify whether javascript sources should be included
         inline rather than loaded from an external CDN. Default: False.

altair_saver/savers/_html.py

@@ -127,6 +127,7 @@ def __init__(
         vegaembed_version: str = alt.VEGAEMBED_VERSION,
         inline: bool = False,
         standalone: Optional[bool] = None,
+        **kwargs,
     ) -> None:
         self._inline = inline
         self._standalone = standalone
@@ -137,6 +138,7 @@ def __init__(
             vega_version=vega_version,
             vegalite_version=vegalite_version,
             vegaembed_version=vegaembed_version,
+            **kwargs,
         )
 
     def _package_url(self, package: str) -> str:

altair_saver/savers/_node.py

@@ -1,8 +1,7 @@
 import functools
 import json
 import shutil
-from typing import Dict, List
-import warnings
+from typing import Dict, List, Optional
 
 from altair_saver.types import JSONDict, MimebundleContent
 from altair_saver._utils import check_output_with_stderr
@@ -42,25 +41,27 @@ def vl2vg(spec: JSONDict) -> JSONDict:
     return json.loads(vg_json)
 
 
-def vg2png(spec: JSONDict) -> bytes:
+def vg2png(spec: JSONDict, vega_cli_options: Optional[List] = None) -> bytes:
     """Generate a PNG image from a Vega spec."""
     vg2png = exec_path("vg2png")
     vg_json = json.dumps(spec).encode()
-    return check_output_with_stderr([vg2png], input=vg_json)
+    return check_output_with_stderr([vg2png, *(vega_cli_options or [])], input=vg_json)
 
 
-def vg2pdf(spec: JSONDict) -> bytes:
+def vg2pdf(spec: JSONDict, vega_cli_options: Optional[List] = None) -> bytes:
     """Generate a PDF image from a Vega spec."""
     vg2pdf = exec_path("vg2pdf")
     vg_json = json.dumps(spec).encode()
-    return check_output_with_stderr([vg2pdf], input=vg_json)
+    return check_output_with_stderr([vg2pdf, *(vega_cli_options or [])], input=vg_json)
 
 
-def vg2svg(spec: JSONDict) -> str:
+def vg2svg(spec: JSONDict, vega_cli_options: Optional[List] = None) -> str:
     """Generate an SVG image from a Vega spec."""
     vg2svg = exec_path("vg2svg")
     vg_json = json.dumps(spec).encode()
-    return check_output_with_stderr([vg2svg], input=vg_json).decode()
+    return check_output_with_stderr(
+        [vg2svg, *(vega_cli_options or [])], input=vg_json
+    ).decode()
 
 
 class NodeSaver(Saver):
@@ -69,6 +70,17 @@ class NodeSaver(Saver):
         "vega": ["pdf", "png", "svg"],
         "vega-lite": ["pdf", "png", "svg", "vega"],
     }
+    _vega_cli_options: List[str]
+
+    def __init__(
+        self,
+        spec: JSONDict,
+        mode: Optional[str] = None,
+        vega_cli_options: Optional[List] = None,
+        **kwargs,
+    ) -> None:
+        self._vega_cli_options = vega_cli_options or []
+        super().__init__(spec=spec, mode=mode, **kwargs)
 
     @classmethod
     def enabled(cls) -> bool:
@@ -78,9 +90,6 @@ def enabled(cls) -> bool:
             return False
 
     def _serialize(self, fmt: str, content_type: str) -> MimebundleContent:
-        if self._embed_options:
-            warnings.warn("embed_options are not supported for method='node'.")
-
         if self._mode not in ["vega", "vega-lite"]:
             raise ValueError("mode must be either 'vega' or 'vega-lite'")
 
@@ -92,10 +101,10 @@ def _serialize(self, fmt: str, content_type: str) -> MimebundleContent:
         if fmt == "vega":
             return spec
         elif fmt == "png":
-            return vg2png(spec)
+            return vg2png(spec, vega_cli_options=self._vega_cli_options)
         elif fmt == "svg":
-            return vg2svg(spec)
+            return vg2svg(spec, vega_cli_options=self._vega_cli_options)
         elif fmt == "pdf":
-            return vg2pdf(spec)
+            return vg2pdf(spec, vega_cli_options=self._vega_cli_options)
         else:
             raise ValueError(f"Unrecognized format: {fmt!r}")

altair_saver/savers/_saver.py

@@ -37,6 +37,7 @@ def __init__(
         vega_version: str = alt.VEGA_VERSION,
         vegalite_version: str = alt.VEGALITE_VERSION,
         vegaembed_version: str = alt.VEGAEMBED_VERSION,
+        **kwargs,
     ):
         if mode is None:
             mode = infer_mode_from_spec(spec)

altair_saver/savers/_selenium.py

@@ -167,6 +167,7 @@ def __init__(
         webdriver: Optional[Union[str, WebDriver]] = None,
         offline: bool = True,
         scale_factor: Optional[float] = 1,
+        **kwargs,
     ) -> None:
         self._driver_timeout = driver_timeout
         self._webdriver = (
@@ -183,6 +184,7 @@ def __init__(
             vega_version=vega_version,
             vegalite_version=vegalite_version,
             vegaembed_version=vegaembed_version,
+            **kwargs,
         )
 
     @classmethod

altair_saver/savers/tests/test_node.py

@@ -1,7 +1,7 @@
 import io
 import json
 import os
-from typing import Any, Dict, IO, Iterator, Tuple
+from typing import Any, Dict, IO, Iterator, List, Optional, Tuple
 
 from PIL import Image
 from PyPDF2 import PdfFileReader
@@ -37,9 +37,12 @@ def get_modes_and_formats() -> Iterator[Tuple[str, str]]:
 
 
 @pytest.mark.parametrize("name,data", get_testcases())
-@pytest.mark.parametrize("mode, fmt", get_modes_and_formats())
-def test_node_mimebundle(name: str, data: Any, mode: str, fmt: str) -> None:
-    saver = NodeSaver(data[mode], mode=mode)
+@pytest.mark.parametrize("mode,fmt", get_modes_and_formats())
+@pytest.mark.parametrize("vega_cli_options", [None, ["--loglevel", "error"]])
+def test_node_mimebundle(
+    name: str, data: Any, mode: str, fmt: str, vega_cli_options: Optional[List[str]]
+) -> None:
+    saver = NodeSaver(data[mode], mode=mode, vega_cli_options=vega_cli_options)
     mimetype, out = saver.mimebundle(fmt).popitem()
     assert mimetype == fmt_to_mimetype(fmt)
     if fmt == "png":

altair_saver/tests/test_core.py

@@ -6,6 +6,8 @@
 import pandas as pd
 import pytest
 
+from _pytest.capture import SysCapture
+
 from altair_saver import (
     available_formats,
     save,
@@ -257,6 +259,53 @@ def test_embed_options_save_html_override(spec: JSONDict) -> None:
     assert f"const embedOpt = {json.dumps(embed_options)};" in html
 
 
+@pytest.mark.parametrize("fmt", ["html", "svg"])
+@pytest.mark.parametrize("vega_cli_options", [None, ["--loglevel", "debug"]])
+def test_save_w_vega_cli_options(
+    monkeypatch: Any,
+    capsys: SysCapture,
+    chart: alt.TopLevelMixin,
+    fmt: str,
+    vega_cli_options: Optional[List],
+) -> None:
+    """Tests that `vega_cli_options` works with both NodeSaver and other Savers"""
+    monkeypatch.setattr(NodeSaver, "enabled", lambda: True)
+    monkeypatch.setattr(SeleniumSaver, "enabled", lambda: False)
+    fp: Union[io.BytesIO, io.StringIO]
+    result = save(chart, fmt=fmt, vega_cli_options=vega_cli_options)
+    assert result is not None
+    check_output(result, fmt)
+
+    stderr = capsys.readouterr().err
+    if vega_cli_options and fmt == "svg":
+        assert "DEBUG" in stderr
+
+
+@pytest.mark.parametrize("vega_cli_options", [None, ["--loglevel", "debug"]])
+def test_render_w_vega_cli_options(
+    monkeypatch: Any,
+    capsys: SysCapture,
+    chart: alt.TopLevelMixin,
+    vega_cli_options: Optional[List],
+) -> None:
+    """Tests that `vega_cli_options` works with both NodeSaver and other Savers"""
+    monkeypatch.setattr(NodeSaver, "enabled", lambda: True)
+    monkeypatch.setattr(SeleniumSaver, "enabled", lambda: False)
+    bundle = render(chart, fmts=["html", "svg"], vega_cli_options=vega_cli_options)
+    assert len(bundle) == 2
+    for mimetype, content in bundle.items():
+        assert content is not None
+        fmt = mimetype_to_fmt(mimetype)
+        if isinstance(content, dict):
+            check_output(json.dumps(content), fmt)
+        else:
+            check_output(content, fmt)
+
+    stderr = capsys.readouterr().err
+    if vega_cli_options:
+        assert "DEBUG" in stderr
+
+
 def test_infer_format(spec: JSONDict) -> None:
     with temporary_filename(suffix=".html") as filename:
         with open(filename, "w") as fp: