Add Tags dimension

specification/dimensions/dimensions.mdpp

@@ -26,5 +26,6 @@ dimensions to categorize, filter, and reveal details in your data when grouped w
 !INCLUDE "servicename.md",1
 !INCLUDE "subaccountid.md",1
 !INCLUDE "subaccountname.md",1
+!INCLUDE "tags.md",1
 
 [FODOFC]: https://www.finops.org/framework/capabilities/

specification/dimensions/tags.md

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+# Tags
+
+Tags are the set of finalized User-Defined and/or Provider-Defined Tags assigned to Tag Sources.  Tags commonly add business context to billing data to identify and accurately allocate charges.
+
+If a Tag is subject to a set of prioritized rules for determining its value, it is finalized after a single value is chosen from a set of corresponding values.  Otherwise, a Tag and a finalized Tag are equal.
+
+Tags adhere to the following requirements:
+
+* Tags MUST only contain finalized tags.
+* Tags MUST standardize to Key-Value Format.
+* A Tag without a specified value MUST have its value set to null.
+* Providers MUST NOT alter User-Defined Tag keys.
+
+Provider-defined Tags additionally adhere to the following requirements:
+
+* Provider-defined Tags MUST be prefixed with a provider-defined prefix.
+* Providers SHOULD publish all provider-defined prefixes within their respective documentation.
+
+## Provider-Defined vs. User-Defined Tags
+
+The following is an example of one User-Defined Tag and one Provider-Defined Tag, respectively, with tag key, foo.  The 1st property is not prefixed, and the Provider has a pre-selected prefix, `marketplace/`, applied to denote that it is a different type of tag.
+
+```json
+    {
+        "foo":"bar",
+        "marketplace/foo": "bar"
+    }
+```
+
+## Finalized Tags
+
+The following example shows a simplified cost and usage data with one metered Account that contains one metered Virtual Machine.  The Provider supports tag inheritance where an Account's User-Defined Tags are applied to all Resources' User-Defined Tags, where applicable.
+
+| ResourceType    | ResourceId | Column                             |
+| :---------------| :----------| :----------------------------------|
+| Account         | my-account | { "team": "web", "env": "prod" }   |
+| Virtual Machine | my-vm      | { "team": "web", *"env": "prod"* } |
+
+After all tag inheritance rules are processed, the finalized cost and usage dataset shows that the Virtual Machine Resource did inherit tag, `env:prod`, from its corresponding Account because no tag with the same key exists.  Conversely, the Virtual Machine Resource did not inherit tag, `team:web`, because the Provider's tag inheritance rules determine that aResource already containing a tag with the same key maintains that same tag.
+
+## Column ID
+
+Tags
+
+## Display Name
+
+Tags
+
+## Description
+
+The set of finalized tags assigned to Tag Sources.
+
+## Content Constraints
+
+|    Constraint   |      Value       |
+|:----------------|:-----------------|
+| Column required | True             |
+| Data type       | Object           |
+| Allows nulls    | True             |
+| Value format    | MUST adhere to KeyValueFormat Attribute |
+
+## Introduced (version)
+
+1.0

supporting_content/dimensions/tags.md

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+# Column: Tags
+
+## Example provider mappings
+
+Current resource types found or extracted from available data sets:
+
+| Provider  | Dataset                 | Column                                      | Hierarchical Resources | Supports Inheritance?
+| :-------- | :---------------------- | :-------------------------------------------| :-------------------------------------------| :----------
+| AWS       | CUR                     | resourceTags/user:\*, costCategories/\*       | Organization, Organizational Unit(s), Account | No
+| GCP       | BigQuery Billing Export | Tags 									 	| Resource Group, Subscription | Yes
+| Microsoft | Cost details            | tags, labels, system_labels, project.labels	| Folder(s), Project | Yes
+
+## Discussion Topics
+
+Discussion / Scratch space:
+- User-defined tags should not have a prefix
+- Provider can create and account for a reserved prefix set
+- Providers should publish known prefixes somewhere
+	- Refer to Numeric Attribute language around provider-publishing guidelines
+- Separator poll?
+	- Double forward slash (Chris Harris)
+	- Pipe (Shawn Alpay)
+- 2 columns: EffectiveTags and RawTags (better names to be decided)
+- Tags
+	- Providers must account for collisions
+	- If inheritance exists for a set of tags, provide the “winning” tag
+	- If inheritance does not exist for a tag, provide all namespaced tags (i.e. costCategory/foo, resourceTags/user:foo)
+	- MUST adhere to the Key-Value attribute spec
+
+- Questions:
+	- Inheritance (e.g., source)?
+	- Merging different datasets (e.g., source)?
+	- Do we split effective tags and raw tags or merge them together with a predefined key format (e.g., “<source>/<key>”)?
+	- Simple JSON key/value pair or array of JSON objects?
+	- What does it look like interpreting labels using Excel formulas only? Would users be required to dl a plugin, use vbscript, etc.
+		- Excel: https://support.microsoft.com/en-au/office/parse-text-as-json-or-xml-power-query-7436916b-210a-4299-83dd-8531a1d5e945 (supports {"foo": "bar"} approach)
+		- Sheets: Seems to require scripting
+	- How do we fit into the top 3 clouds?
+	- Should we give an opinion around requiring k/v tags?
+	- Create a poll around calling the dimension “Tags” or “Labels”?
+		- “Custom Tags/Labels”?
+		- One key/value pair for all tags “tags”: [ … ]
+	- Which raw format do we go with?
+