A generic JSON file updater, which can add/update-existing attributes. (

sonic-net#770)

* A generic JSON file updater, which can add/update-existing attributes.
This tool would be used to update /etc/sonic/core_analyzer.rc.json file to add
credentials by HW proxy.

* Updated per review comments.
The option is better named.

scripts/update_json.py

@@ -0,0 +1,55 @@
+#! /usr/bin/env python
+
+import os
+import sys
+import json
+import argparse
+
+TMP_SUFFIX = ".tmp"
+BAK_SUFFIX = ".bak"
+
+def dict_update(dst, patch):
+    for k in patch.keys():
+        if type(patch[k]) == dict:
+            dst[k] = dict_update(dst[k], patch[k])
+        else:
+            dst[k] = patch[k]
+    return dst
+
+def do_update(rcf, patchf):
+    dst = {}
+    patch = {}
+
+    tmpf = rcf + TMP_SUFFIX
+    bakf = rcf + BAK_SUFFIX
+
+    with open(rcf, "r") as f:
+        dst = json.load(f)
+
+    with open(patchf, "r") as f:
+        patch = json.load(f)
+
+    dst = dict_update(dst, patch)
+
+    with open(tmpf, "w") as f:
+        json.dump(dst, f, indent = 4)
+
+    os.rename(rcf, bakf)
+    os.rename(tmpf, rcf)
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Update JSON based file")
+    parser.add_argument("-u", "--update", help="JSON file to be updated")
+    parser.add_argument("-p", "--patch", help="JSON file holding patch")
+    args = parser.parse_args()
+
+    if not args.update or not args.patch:
+        raise Exception("check usage")
+
+    do_update(args.update, args.patch)
+
+if __name__ == '__main__':
+    main()
+
+

setup.py

@@ -90,6 +90,7 @@
         'scripts/route_check_test.sh',
         'scripts/sfpshow',
         'scripts/teamshow',
+        'scripts/update_json.py',
         'scripts/warm-reboot',
         'scripts/watermarkstat',
         'scripts/watermarkcfg'