Refactor and Enhance SmartLinks

[evomimic]

As we gear up to add MAP Descriptors and the Query Engine to the architecture, we need to flesh out and simplify more of the SmartLinks model.

Dependencies

None

Current State

• SmartLink functionality is scattered across several files and should be consolidated:
  • smartlink_manager.rs defines SmartLinkInput struct and create_smart_link(), create_link_tag() functions
  • smartlink.rs defines AddSmartLinkInput, RemoveSmartLinkInput structs and smartlink_tag_header_length(), add_smartlink(), get_smartlinks_for_holon_node(), remove_smartlink(), get_relationship_name_from_smartlink() functions
  • holon_collection.rs has save_smartlinks_for_collection() functions
  • relationship.rs defines SmartLinkHolder struct and build_relationship_map_from_smartlinks() and get_relationship_links() functions

Proposal

Consolidate SmartLink related functionality into the smartlink.rs file. This file should define all of the SmartLink related data structures and behaviors.

In the smartlink.rs file

• [x] Replace AddSmartlinkInput with SmartLink. A single data structure used as the transfer object to/from holochain links

  pub struct SmartLink {
  pub from_address: HolonId,
  pub to_address: HolonId,
  pub relationship_name: RelationshipName, // temporarily using RelationshipName as descriptor
  pub smart_property_values: Option<PropertyMap>,
  }

• [x] Move create_link_tag and create_smart_link from _smart_linkmanager.rs to smartlink.rs

• [x] Rename create_smart_link as save_smart_link(input: SmartLink)->Result<(),HolonError>

• [x] Replace get_relationship_name_from_smartlink with pub fn get_smartlink_from_link(link:Link)->Result<SmartLink, HolonError>

  • This function decodes the Link structure and populates and returns a SmartLink struct

• [x] Comment out the get_smartlinks_for_holon_node function. It was generated by the scaffolding tool and in addition to getting the links, it also gets the target holons. We don't want/need that behavior.

• [x] Comment out the add_smartlink() function (it is being replaced by the save_smartlink function)

In the holon.rs file

• [x] Move the get_relationship_links function and the build_relationship_map_from_smartlinks() function from relationship.rs to holon.rs
• [x] Rename build_relationship_map_from_smartlinks() to:

  pub fn load_relationship_map(
  context: &HolonsContext,
  source_holon_id: ActionHash,
  relationship_name: Option<RelationshipName>,
  ) -> Result<RelationshipMap, HolonError> 

  • get the links from the persistent store using get_relationship_links
  • for each link, get_smartlink_from_link and update the reference_map using .entry(name).or_insert_with(Vec::new).push(reference);
  • build and return the relationship_map from the reference_map

In the holon_collection.rs file

• [x] Change the implementation of save_smartlinks_for_collection to build a SmartLink object for each collection member and then call the save_smart_link function provided by the smartlink.rs file

Delete the smart_link_manager.rs file

• [x] Resolve any issues arising from this deletion.

In the relationship.rs file

• [x] Delete SmartLinkHolder
• [x] Delete 'build_relationship_map_from_smartlinks (moved to holon.rs)
• [x] Delete get_relationship_links (moved to holon.rs)
• [x] Clean up any issues created by this deletion

Testing

There is still no code that invokes the load_realationship_map function, so there is no real way to test if that function works, but we can ensure nothing else breaks.

Definition of Done

There is still no code that invokes the load_realationship_map function, so there is no real way to test if that function works, but we can ensure nothing else breaks.

• [x] All existing sweetest cases pass
• [x] The tryorama tests all pass

[dauphin3]

@evomimic for create_link_tag() how are the smart_property_values concatenated into a String?

https://github.com/evomimic/map-holons/wiki/SmartLink-Manager says "Null-separated values (serialized into a String) for each of the properties listed in the access_path for this SmartLink. These values allow the Query Engine to filter/sort SmartLinks without having to fetch the target holon."

so I know that we are doing away with access paths and now just passing through the property values themselves, but my question is twofold:

1. when creating the bytes, am I pushing bytes.extend_from_slice(UNICODE_NUL_STR.as_bytes()); after each value?
2. does the property name get included in the String, and if so, how should that look?

[dauphin3]

@evomimic should we be passing smart_property_values into get_relationship_links() ? or is that unnecessary as it is not a filter that will be used in this function? if so, should that feature also be added to load_relationship_map() ?

[evomimic]

@evomimic should we be passing smart_property_values into get_relationship_links() ? or is that unnecessary as it is not a filter that will be used in this function? if so, should that feature also be added to load_relationship_map() ?

No. Under the current design, we always load all links for a relationship into the Shared Objects Layer. Filtering is only applied in the Query Layer.

[evomimic]

@evomimic for create_link_tag() how are the smart_property_values concatenated into a String? I know that we are doing away with access paths and now just passing through the property values themselves, but my question is twofold:

1. when creating the bytes, am I pushing bytes.extend_from_slice(UNICODE_NUL_STR.as_bytes()); after each value?
2. does the property name get included in the String, and if so, how should that look?

I have updated SmartLink Manager wiki with answers to both questions. We ARE storing both property_names and property_values in the SmartLink. See the wiki page for delimiters used.

[dauphin3]

@evomimic when parsing the link tag to build the PropertyMap, there is currently no way to identify the PropertyValue as the corresponding BaseValue type. A potential solution is to add another separator symbol after Ⓥ. We would need one for each: StringValue, IntegerValue, BooleanValue, EnumValue

[evomimic]

@dauphin3 : Yea... more problems arising due to lack of descriptors.

For the short term, the only value I need in the SmartLink is the key value (if defined) and that is a MapString. Here's the short-term workaround:

in holon_collection.rs / save_smartlinks_for_collection function:

• [x] in the for loop, use holon_reference.get_key to retrieve the holon's key. If not None, add a property to the SmartLink, use "key" as the property_name and the results of the get_key call as the value.
• [x] in the get_smartlink_from_link function, always assume MapString as the value type for smart properties.

in the smart_reference.rs file

Instead of getting the key from the referenced holon (which forces retrieval of the holon), we should get the key from the SmartLink itself.

• [x] Add a get_key->Result<Option<MapString>, HolonError> method. For now, the implementation of this method should get the MapString value for the "key" property. If no value found, return None. Otherwise return the key value.

[dauphin3]

Change signature of create_link_tag to create_link_tag(input: SmartLink)->LinkTag

• Encode relationship_name and smart_property_values (if supplied) in the tag

@evomimic I am using this fn to build a link_tag from the possible parameters it could contain, and so for example in get_relationship_links() I don't have all of the necessary info to pass an entire Smartlink but still need to create a link_tag for filtering reasons and therefore some options could be: 1) keep unchanged 2) have 2 fns create_link_tag_from_smartlink and create_link_tag_xx ie create_link_tag_from_parameters etc 3) keep as is in this issue and then determine some other logic for get_relationship_links 4) construct a different, all encompassing function -- or alternative set of fns

[evomimic]

Change signature of create_link_tag to create_link_tag(input: SmartLink)->LinkTag

• Encode relationship_name and smart_property_values (if supplied) in the tag

@evomimic I am using this fn to build a link_tag from the possible parameters it could contain, and so for example in get_relationship_links() I don't have all of the necessary info to pass an entire Smartlink but still need to create a link_tag for filtering reasons and therefore some options could be:

1. keep unchanged
2. have 2 fns create_link_tag_from_smartlink and create_link_tag_xx ie create_link_tag_from_parameters etc
3. keep as is in this issue and then determine some other logic for get_relationship_links
4. construct a different, all encompassing function -- or alternative set of fns

Change signature of create_link_tag to create_link_tag(input: SmartLink)->LinkTag

• Encode relationship_name and smart_property_values (if supplied) in the tag

@evomimic I am using this fn to build a link_tag from the possible parameters it could contain, and so for example in get_relationship_links() I don't have all of the necessary info to pass an entire Smartlink but still need to create a link_tag for filtering reasons and therefore some options could be:

1. keep unchanged
2. have 2 fns create_link_tag_from_smartlink and create_link_tag_xx ie create_link_tag_from_parameters etc
3. keep as is in this issue and then determine some other logic for get_relationship_links
4. construct a different, all encompassing function -- or alternative set of fns

You're right. SmartLink is overkill as input parameter to create_link_tag. Let's use keep what we have for now (option 1).