resolves #320 read from stdin and write to stdout#321
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This was referenced May 13, 2024
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Lets the CLI participate in unix pipelines:
cat harness.yml | wireviz -f s -O - - > harness.svg
cat harness.yml | wireviz -f p -O - - > harness.png
wireviz -f h -O - harness.yml > harness.html
Pass `-` as the input filename to read YAML from stdin, and pass `-` to
either `--output-dir` or `--output-name` to write the rendered output to
stdout. When writing to stdout exactly one format may be requested.
Two refactors enable this:
1. Harness.output() now computes every requested format in memory via
`Harness._render()` (graph.pipe(format=...) + embed_svg_images on a
string) instead of the previous `graph.render()` -> `.tmp.svg` ->
embed_svg_images_file -> rename dance. The caller dispatches the
resulting `{fmt: bytes|str}` dict to either files or stdout.
2. generate_html_output() now takes the SVG as a string and returns the
HTML string rather than reading a tmp.svg from disk and writing the
.html file itself. New optional `output_dir` / `output_name` /
`png_b64` parameters preserve the `<!-- %filename% -->` and
`<!-- %diagram_png_b64% -->` template placeholders in file mode and
leave them empty/unresolved in stdout mode.
Library-level `print()` warnings in DataClasses.py, Harness.py,
wv_colors.py, wv_helper.py, and wireviz.py are routed to `sys.stderr`
so stdout stays clean of log noise when piped. CLI status banners in
wv_cli.py go to stderr for the same reason.
Also drops the now-unused `embed_svg_images_file` helper.
Ported to master from wireviz#321
(originally targeting `dev` by Guillaume Grossetie / @ggrossetie,
resolves wireviz#320). The PR was rebased / adapted to current master's
file_read_text/file_write_text helpers and current Harness.output
signature; the in-memory render dict and stdout dispatch are the
load-bearing additions.
Verification:
- All 14 examples + 8 tutorials + 2 demos rebuild without errors.
- Deterministic outputs (.gv, .bom.tsv) byte-identical to baseline ->
no behavior change in file mode.
- Verified stdin->stdout for SVG (text) and PNG (binary).
- Multi-format-to-stdout correctly rejected with a clear error.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
SomethingNew71
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Add stdin/stdout streaming (port of upstream PR wireviz#321)
SomethingNew71
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…eam PR wireviz#234) Renders now embed the source YAML in PNG output as a zlib-compressed iTXt chunk under the key ``wireviz:yaml``. The CLI auto-detects ``.png`` inputs and pulls the YAML back out, so a single PNG file is enough to re-render or edit a harness — no sidecar .yml needed. The headline workflow: wireviz harness.yml # produces harness.png with yaml inside wireviz harness.png # round-trips: extract YAML, re-render This is the load-bearing capability for the upcoming wireviz-gui: drag a PNG into the editor and recover the source. Without it, every PNG in the wild is an opaque artifact divorced from its model. API surface: * wireviz.parse() gains ``embed_yaml: bool = True``. The default embeds; pass False to render plain PNGs without source-bearing metadata. * Harness.output() / _render() gain ``yaml_source: Optional[str]``. When non-None and PNG is in the requested formats, the rendered PNG bytes are post-processed through PIL to attach the iTXt chunk. * New module-level helpers in Harness.py: - PNG_YAML_CHUNK_KEY = "wireviz:yaml" - _embed_yaml_in_png(png_bytes, yaml_source) -> bytes - read_yaml_from_png(png_path) -> Optional[str] * CLI ``--no-embed-yaml`` flag opts out of embedding when desired (e.g. before sharing a diagram externally without source). Implementation notes: * The chunk uses ``iTXt`` (international text, zip-compressed) rather than ``zTXt`` so unicode YAML round-trips cleanly. Key prefix ``wireviz:`` namespaces the chunk against PNG software-defined keywords. * When parse() is called with a Dict input, we yaml.safe_dump it back for embedding — round-trip-readable, but without the original comments or formatting (those don't survive the dict-conversion step regardless of embedding). * build_examples.py opts out (``embed_yaml=False``) so the regression baseline PNGs stay deterministic. Adapted from wireviz#234 (originally by @jacobian91, targeting upstream ``dev``). The 2021-era PR was heavily bit-rotted — argparse, the old parse_cmdline / parse_file layer, conceal-input enum — only the load-bearing idea (zTXT/iTXt embed in PNG, .png input recovery) was preserved. Reworked against current master's click CLI, the in-memory render dict from PR wireviz#321 stdin/stdout, and threaded source_path / template_dir from earlier PRs in this chain. Verified: * round-trip: harness.yml → harness.png → re-extract → identical YAML * --no-embed-yaml produces a PNG without the chunk (verified via PIL) * ``wireviz harness.png`` on a chunk-less PNG raises a clean click.UsageError * build_examples.py runs cleanly; .gv and .bom.tsv byte-identical to baseline. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Implements the ``pdf`` output format that's been a TODO stub since
v0.4.1. Pipes the graph through Graphviz's PDF renderer
(``graph.pipe(format="pdf")``) and dispatches the bytes the same way
PNG goes — to a file in normal mode, to ``sys.stdout.buffer`` in
stdout mode.
Usage:
wireviz -f P harness.yml # produces harness.pdf
cat harness.yml | wireviz -f P -O - - # stdout, binary
CLI flag changes:
* ``"P": "pdf"`` un-commented in ``format_codes`` (use ``-f P``)
* "PDF output is not yet supported" stderr warning removed from
Harness.output()
Adapted from wireviz#367 (originally
by @tobiasfalk, targeting upstream ``dev``). The upstream patch went
through the old ``graph.render()`` + temp-file path — this port uses
the in-memory ``graph.pipe()`` wired up by the stdin/stdout refactor
(PR wireviz#321), so PDF works in both file mode AND stdout mode without
extra plumbing.
Verified:
* ``wireviz -f P harness.yml`` produces a valid PDF (file 1.7).
* ``cat harness.yml | wireviz -f P -O - -`` writes valid PDF to stdout.
* build_examples.py: deterministic outputs (.gv, .bom.tsv) byte-
identical (no example .yml has been switched to request PDF
rendering — keeping that out of the regression baseline since PDF
bytes from graphviz vary by version).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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What I Did
printbysys.stderr.write(otherwisestdoutwill contain both output results sent and warning/log messages)generate_html_outputto take an input rather than a filenameembed_svg_images_filemove the logic in the output functionhtmlandsvgbom_listonly once if the formats option contains bothhtmlandtsvUsage
Read stdin, write output to stdout (redirect to out.svg)
$ cat out.svgout.svg
Read input.yml, write output to stdout (redirect to out.svg)
Read input.yml, write all outputs to stdout (redirect to out.txt)
out.txt
Read from stdin, output to stdout:
$ cat input.yml | python3 src/wireviz/wv_cli.py -resolves #320