Issue 6552 - Support arbitrary manifest values

chainedconfigparser.py

Index: chainedconfigparser.py
diff --git a/chainedconfigparser.py b/chainedconfigparser.py
index ce26b04b50e175e1cbd99a772f2a589acd1ac64c..504ecc3303f214d85ede2da3a325616d167670dd 100644
--- a/chainedconfigparser.py
+++ b/chainedconfigparser.py
@@ -93,15 +93,15 @@ class ChainedConfigParser(ConfigParser.SafeConfigParser):
             except ConfigParser.NoOptionError:
                 raise DiffForUnknownOptionError(option, section)
 
-            orig_values = orig_value.split()
-            diff_values = value.split()
+            orig_values = orig_value.splitlines()
+            diff_values = value.splitlines()
 
             if is_addition:
                 new_values = orig_values + [v for v in diff_values if v not in orig_values]
             else:
                 new_values = [v for v in orig_values if v not in diff_values]
 
-            value = ' '.join(new_values)
+            value = '\n'.join(new_values)
 
         return is_diff, option, value
 
@@ -157,6 +157,79 @@ class ChainedConfigParser(ConfigParser.SafeConfigParser):
                 raise ConfigParser.NoSectionError(section)
             raise ConfigParser.NoOptionError(option, section)
 
+    def section_as_dict(self, section, base):
+        """Parse a given section into a dictionary.
+
+        Parse arbitrary key/value pairs from 'section' of the current
+        configuration into a dictionary and deep merge it into `base`.
+
+        The following rules need to be considered:
+
+        * An option's key may be declared as a series of nested dictionary keys,
+          seperated by '.'.
+        * Declaring an option's value in a new line (even if only one is given)
+          will define the option's value as an array.

[Sebastian Noack, 2018/04/19 10:50:56]

Nit: Talking about "arrays" made sense initially when we used JSON terminology
here. But since we no longer do, as this function is agnostic of JSON, we also
might want to change "array" to "list" (Python).

[tlucas, 2018/04/19 11:08:13]

Done.

+        * When an option's value is defined as an array, no other nested
+          objects may follow.
+        * An array is expandable by the ConfigParser's '+=' token (Note: A
+          previously declared string will be converted into an array).
+        * Values may be marked as `number` or `bool` by prefixing them
+          accordingly (this also applies to values in an array):
+          * bool:<value>
+          * number:<value>
+
+        Example:
+                                    {
+        foo = foo                     "foo": "foo",
+        asd =                         "asd": ["asd"],
+            asd                       "bar": {

[Sebastian Noack, 2018/04/19 10:50:57]

Nit: For consistency, we might want to use two space indentation on the
left-hand side here as well.

[tlucas, 2018/04/19 11:08:14]

Done.

+        bar.baz = a                     "baz": ["a", "c", "d"]
+        baz.foo = a                   },
+        baz.z =                       "baz": {
+            bar                         "foo": "a",
+            bool:true           ===>    "z": ["bar", true]
+        bar.baz +=                    },
+            c                         "bad": true,
+            d                         "good": false,
+        bad = bool:true               "is": {
+        good = bool:false               "integer": 1,
+        is.integer = number:1           "float": 1.4
+        is.float = number:1.4         }
+                                    }
+        """
+        def parse_values(v):

[Sebastian Noack, 2018/04/19 10:50:57]

Nit; since this function is only called with a single value now, we might want
to use singular: "parse_values" => "parse_value"

[tlucas, 2018/04/19 11:08:13]

Done.

+            if isinstance(v, list):
+                return [parse_values(x) for x in v]

[Sebastian Noack, 2018/04/19 10:50:57]

This code path can be removed now, since we no longer this function with a list.

[tlucas, 2018/04/19 11:08:14]

Done.

+
+            if v.startswith('number:'):
+                v = v.split(':', 1)[1]
+                try:
+                    return int(v)
+                except ValueError:
+                    return float(v)
+            if v == 'bool:true':
+                return True
+            if v == 'bool:false':
+                return False
+            return v
+
+        data = self.items(section)

[Sebastian Noack, 2018/04/19 10:50:56]

Nit: this variable is only used once, perhaps inline it below?

[tlucas, 2018/04/19 11:08:14]

Done.

One note: Not catching a NoSectionError here would explicitly force [manifest]
to be present in the metadata.*, even if it's empty.

I might check for presence first, what do you think?

[tlucas, 2018/04/19 11:45:15]

Done.

+
+        for k, v in data:
+

[Sebastian Noack, 2018/04/19 10:50:58]

Nit: Is the blank line here intended? It looks weird, I don't recall seeing
blank lines after a loop header anywhere else in our code.

[tlucas, 2018/04/19 11:08:15]

Done.

+            parents = k.split('.')
+            tail = parents.pop()
+            current = base
+            for name in parents:
+                current = base.setdefault(name, {})
+
+            if '\n' in v:
+                current[tail] = [parse_values(x) for x in v.splitlines() if x]
+            else:
+                current[tail] = parse_values(v)
+
+        return base

[Sebastian Noack, 2018/04/19 10:50:57]

Nit: Returning the dictionary seems redundant. It's the same object passed in by
the calling code, hence the calling code already has it. You merely can chain
the function call in a single line, but therefore you have one more line here.
On the other hand, if this function doesn't return it there is no potential
confusion about the object being modified in-place. However, then we might want
to rename this function to add_section_to_dict() or serialize_section().

[tlucas, 2018/04/19 11:08:14]

I wouldn't mind either solution - but we also might want to rename the method,
when we're not returning anything anymore into e.g. merge_section_into().

What's your favorite? 

[Sebastian Noack, 2018/04/19 11:12:41]

That is exactly what I said. My suggestions above were add_section_to_dict() and
serialize_section(); merge_section_into() is good to.

[tlucas, 2018/04/19 11:45:15]

Done.

+
     def readfp(self, fp, filename=None):
         raise NotImplementedError