cluster.py: generate individual cluster files in a subdirectory

mossutils/cluster.py

 import re
+import os
 # import argparse
 import logging
 import csv
@@ -21,7 +22,7 @@ from .utils import logging as logutils
 
 DEFAULT_RESULTS_CSV_FILE="moss-report.csv"
 DEFAULT_TOTAL_GRAPH_DOT_FILE="moss-report.dot"
-DEFAULT_CLUSTERS_DOT_FILE="clusters.dot"
+DEFAULT_CLUSTER_FILES_DIR="_clusters"
 DEFAULT_CLUSTER_FILE_PATTERN="cluster-{}.{}"
 DEFAULT_THRESHOLD_PERCENTAGE=90
 DEFAULT_THRESHOLD_LINES=50
@@ -109,13 +110,16 @@ def get_results_graph(results, percentage_threshold, lines_threshold):
     edge = (result.id1, result.id2, weight)
     color = get_color(weight)
 
+    # TODO: Don't hardcode ../ path prefix
+    match_url = "../{}".format(result.match_file)
+
     attributes = {
       # Attributes for GraphViz
       "color": color,
       "penwidth": 2,
       "label": "{0}% ({1})".format(weight, result.lines),
-      "labelURL": result.match_file,
-      "URL": result.match_file,
+      "labelURL": match_url,
+      "URL": match_url,
       "target": "match",
       "fontcolor": color,
       # Attributes for internal bookkeeping
@@ -195,6 +199,7 @@ def create_summary_csv_file(cluster_entries, summary_csv_file):
 def main(
     results_csv_file=DEFAULT_RESULTS_CSV_FILE,
     total_graph_dot_file=DEFAULT_TOTAL_GRAPH_DOT_FILE,
+    cluster_files_dir=DEFAULT_CLUSTER_FILES_DIR,
     cluster_file_pattern=DEFAULT_CLUSTER_FILE_PATTERN,
     percentage_threshold=DEFAULT_THRESHOLD_PERCENTAGE,
     lines_threshold=DEFAULT_THRESHOLD_LINES,
@@ -209,7 +214,13 @@ def main(
   logging.info("Writing total graph to {}".format(total_graph_dot_file))
   nx.drawing.nx_pydot.write_dot(graph, total_graph_dot_file)
 
-  cluster_entries = create_clusters(graph, cluster_file_pattern, create_svg_files)
+  logging.info("Creating directory {}".format(cluster_files_dir))
+  os.makedirs(cluster_files_dir, exist_ok=True)
+
+  cluster_entries = create_clusters(
+      graph, 
+      os.path.join(cluster_files_dir, cluster_file_pattern),
+      create_svg_files)
 
   create_summary_csv_file(cluster_entries, summary_csv_file)