[doc] Improve CI jobs graph generation (#804)

Align `jobs_graph.py` to generate the actual svg with the same layout

Author: aobolensk

docs/_static/ci_graph.svg

@@ -1,16 +1,14 @@
+import argparse
 import os
+import subprocess
 
 try:
     import yaml
 except ImportError:
     print("Please install pyyaml: pip install pyyaml")
     exit(1)
 
-try:
-    import graphviz
-except ImportError:
-    print("Please install graphviz: pip install graphviz")
-    exit(1)
+EXCLUDED_JOBS = {"ci-scope"}
 
 
 def parse_gha_yml(file_path):
@@ -20,27 +18,96 @@ def parse_gha_yml(file_path):
 
 
 def build_jobs_graph(gha_data):
-    jobs = gha_data.get("jobs", {})
-    dot = graphviz.Digraph()
+    jobs = filter_jobs(gha_data.get("jobs", {}))
+    dot = [
+        "digraph CI_Overview {",
+        '  graph [rankdir="LR", ranksep="1.0", nodesep="0.5", splines="ortho"];',
+        '  node [shape="box", style="rounded", fontname="Helvetica"];',
+        '  edge [color="#333333"];',
+    ]
 
     for job_name, job_data in jobs.items():
-        dot.node(job_name)
+        dot.append(f"  {quote_dot_id(job_name)};")
         needs = job_data.get("needs", [])
         if isinstance(needs, str):
             needs = [needs]
         for dependency in needs:
-            dot.edge(dependency, job_name)
+            if dependency not in jobs:
+                continue
+            dot.append(f"  {quote_dot_id(dependency)} -> {quote_dot_id(job_name)};")
+
+    for rank_jobs in get_ranked_jobs(jobs).values():
+        same_rank_jobs = " ".join(
+            f"{quote_dot_id(job_name)};" for job_name in rank_jobs
+        )
+        dot.append(f"  {{ rank=same; {same_rank_jobs} }}")
+
+    dot.append("}")
+    return "\n".join(dot)
+
+
+def filter_jobs(jobs):
+    return {
+        job_name: job_data
+        for job_name, job_data in jobs.items()
+        if job_name not in EXCLUDED_JOBS
+    }
+
+
+def quote_dot_id(value):
+    return f'"{value.replace("\\", "\\\\").replace('"', '\\"')}"'
+
 
-    return dot
+def get_ranked_jobs(jobs):
+    ranks = {}
+
+    def get_rank(job_name):
+        if job_name in ranks:
+            return ranks[job_name]
+
+        needs = jobs[job_name].get("needs", [])
+        if isinstance(needs, str):
+            needs = [needs]
+        needs = [dependency for dependency in needs if dependency in jobs]
+
+        if not needs:
+            ranks[job_name] = 0
+        else:
+            ranks[job_name] = max(get_rank(dependency) for dependency in needs) + 1
+        return ranks[job_name]
+
+    for job_name in jobs:
+        get_rank(job_name)
+
+    ranked_jobs = {}
+    for job_name, rank in ranks.items():
+        ranked_jobs.setdefault(rank, []).append(job_name)
+    return ranked_jobs
 
 
 def save_graph(dot, filename, file_format):
-    dot.render(filename, format=file_format, cleanup=True)
+    subprocess.run(
+        ["dot", f"-T{file_format}", "-o", f"{filename}.{file_format}"],
+        input=dot,
+        text=True,
+        check=True,
+    )
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="Generate a Graphviz CI jobs graph from a GitHub Actions workflow."
+    )
+    parser.add_argument(
+        "--workflow", default=os.path.join(".github", "workflows", "main.yml")
+    )
+    parser.add_argument("--out", default=os.path.join("docs", "_static", "ci_graph"))
+    parser.add_argument("--format", default="svg")
+    return parser.parse_args()
 
 
 if __name__ == "__main__":
-    gha_file_path = os.path.join(".github", "workflows", "main.yml")
-    svg_path = os.path.join("docs", "_static", "ci_graph")
-    gha_data = parse_gha_yml(gha_file_path)
+    args = parse_args()
+    gha_data = parse_gha_yml(args.workflow)
     jobs_graph = build_jobs_graph(gha_data)
-    save_graph(jobs_graph, svg_path, "svg")
+    save_graph(jobs_graph, args.out, args.format)