DOCS: object detection usecase

utils/get_interfaces.py

@@ -0,0 +1,68 @@
+import argparse
+import os
+import json
+import subprocess
+import signal
+import time
+
+from ros2cli.node.strategy import NodeStrategy
+from ros2topic.api import get_topic_names_and_types
+
+OUTPUT_FILE = "topics.json"
+TOPICS_FILTER = ["/parameter_events", "/rosout"]
+
+def get_script_args(cfg):
+    args = cfg["command"].split()
+    args.append(cfg["package"])
+    args.append(cfg["executable"])
+    return args
+
+def get_topics(filename, path):
+    jsonpath = os.path.join(path, filename)
+
+    with NodeStrategy({}) as node:
+        topic_names_and_types = get_topic_names_and_types(node=node, include_hidden_topics=False)
+
+    topic_info = []
+    for (topic_name, topic_types) in topic_names_and_types:
+        if not topic_name in TOPICS_FILTER:
+            topic_info.append({"name": topic_name, "type": topic_types[0]})
+
+    print(f"---> number of topics: {len(topic_info)}")
+
+    j_data = {"topics": topic_info}
+    with open(jsonpath, "w") as fh:
+        json.dump(j_data, fh, indent=2)
+
+    for topic in topic_info:
+        print(topic["name"])
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--package", required=True, help="Json-string/file with package parameters")
+    parser.add_argument("--path", default="", help="Output path")
+    parser.add_argument("--json", default=OUTPUT_FILE, help="Output file name in json-format")
+    parser.add_argument('--delay', default=5, type=int, help="Delay in seconds")
+    args = parser.parse_args()
+
+    if args.package[-5:] == ".json":
+        if not os.path.isfile(args.package):
+            print(f"Error: no such file '{args.package}'")
+            exit(-1)
+        with open(args.package, "r") as f:
+            j_data = f.read()
+    else:
+        j_data = args.package
+    try:
+        cfg = json.loads(j_data)
+    except json.JSONDecodeError as e:
+        print(f"JSon error: {e}")
+        exit(-2)
+
+    cmd = get_script_args(cfg)
+    process = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    time.sleep(args.delay)
+    get_topics(args.json, args.path)
+
+    process.send_signal(signal.SIGINT)