oe/data: Add export2json function

The export2json function export the variables contained in
the data store to JSON format, the main usage for now will be
to provide test data to QA framework.

(From OE-Core rev: 57c7bf68ed66a56601e1431bb2db750c5742b5ce)

Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/data.py

@@ -1,3 +1,4 @@
+import json
 import oe.maketype
 
 def typed_value(key, d):
@@ -15,3 +16,30 @@ def typed_value(key, d):
         return oe.maketype.create(d.getVar(key) or '', var_type, **flags)
     except (TypeError, ValueError) as exc:
         bb.msg.fatal("Data", "%s: %s" % (key, str(exc)))
+
+def export2json(d, json_file, expand=True):
+    data2export = {}
+    keys2export = []
+
+    for key in d.keys():
+        if key.startswith("_"):
+            continue
+        elif key.startswith("BB"):
+            continue
+        elif key.startswith("B_pn"):
+            continue
+        elif key.startswith("do_"):
+            continue
+        elif d.getVarFlag(key, "func", True):
+            continue
+
+        keys2export.append(key)
+
+    for key in keys2export:
+        try:
+            data2export[key] = d.getVar(key, expand)
+        except bb.data_smart.ExpansionError:
+            data2export[key] = ''
+
+    with open(json_file, "w") as f:
+        json.dump(data2export, f, skipkeys=True, indent=4, sort_keys=True)