Director Service Communication Diagrams

The following diagrams depict existing procedure calls to the Director service. Included are interactions with the Director’s inner representations to better understand their signatures.

Director-Envoy Communication

The following diagram depicts a typical process of establishing a Federation and registering an experiment.

        sequenceDiagram
    participant D as Director
    participant E as Envoy
    rect rgb(0, 255, 0,.1)
        Note over D,E: A Federation startup process
        D->D: Starts
        E->E: Starts and loads local Shard Descriptor
        E-->>D: Connects using FQDN and certificate
        E-->>+D: Communicates dataset info
        D-->D: Ensures unified data interface
        D-->>-E: Approves
        D-->D: Keeps a list of connected Envoys
        
    end
    Note over D,E: We consider a Federation set up
    rect rgb(0, 0, 255,.05)
        Note over D,E: An Experiment's start
        D->D: Registers a model, FL tasks and an FL plan
        D->D:Starts an Aggregator with a toy plan
        Note left of D: An Envoy with dummy data is <br>started locally
        opt Test run failed
            D-->D: Notifies user that <br>the experiment is inconsistent
            D-->D: The experiment ends
        end
        D->D: Reviews the FL plan
        D->D: Starts an Aggregator
        D-->>E: Sends the experiment archive <br>and the FL plan to envoys
        E-->E: Reviews the FL Plan
        E-->E: Starts a Collaborator
        D-->D: Fills the model with the final weights <br>and returns to user
    end
    Note over D,E: The Experiment ended. <br> The Federation keeps existing.
    

Basic Scenario of Director-Envoy Communication

Director Side Envoy Representation and Related Remote Procedure Calls

This diagram shows possible interactions with Envoy handles on the Director side.

        sequenceDiagram
  participant ER as Envoy Representation
  participant D as Director
  participant E as Envoy
  participant F as Frontend API

  E-)+D: Acknowledge Shard request
  note over ER,D: Envoy registry is a dict-like object
  D->>ER: Creates and puts to the Registry
  activate ER
  D->>-E: Approves
  loop Healthcheck timeout
    E-)+D: Sends status
    D->>ER: Adds info or updates ER state
    activate ER
    D->>-E: Acknowledges
  end
  rect rgb(225, 255, 225)
    Note over D: API requests may overlap <br>with the healthcheck loop
    F-)+D: Requests Shard Registry
    D->>ER: Gets required info
    D->>-F: Replies with the Registry state
  end
  D-->E: Disconnect
  D-->D: Waits for several Healthcheck timeouts
  D->>ER: Removes from the Registry
  deactivate ER
  deactivate ER
  Note over ER: Will not be included in the next <br>API Registry request
            
    

Communications Altering or Requesting Envoy-Related Information

Director Side Experiment Representation and Related Remote Procedure Calls

This diagram shows possible interactions with Experiment handles on the Director side.

        sequenceDiagram
  participant ER as Experiment Representation
  participant D as Director
  participant E as Envoy
  participant F as Frontend API

  F->>+D: Set New Experiment
  D->>+ER: Creates ER and puts in the registry
  note over ER,D: Experiment registry is a queue-like object
  D->>-F: Approves

  F->>+D: Get Registered experiments
  D->>ER: Gets name and status
  note over ER,D: Registry can also return <br>an experiment list by user id
  D->>-F: Approves

  F->>+D: Get Experiment Status
  D->>+ER: Gets the status of the current experiment
  note over ER,D: Experiment might be pending, in progress, failed or finished
  D->>-F: Approves

  rect rgb(225, 255, 225)
    note over ER,E: Envoys may start awaiting experiments <br>even if the queue is empty
    E-)+D: Wait Experiment *STREAM*
    note over ER,D: Assuming the Experiment is the next in the queue <br>and the Envoy is assigned for this Experiment
    D->>ER: Gets experiment name (pop operation)
    D->>-E: Wait Experiment Response

    E->>+D: Get Experiment Data
    D->>ER: Gets experiment archive (by name)
    D-->D: Reviews the FL Plan
    D->>ER: Sets status to In Progress
    D->>-E: Experiment Data
  end

  rect rgb(255, 225, 225)
  note over ER,E: The Experiment execution
    D-->D: Starts an aggregator that orchestrates experiment
    D->>ER: Removes experiment archive
    D-->D: Finishes the experiment and releases involved Envoys
    D->>+ER: Puts training artifacts
    D->>ER: Sets status to Finished
  end

  rect rgb(225, 225, 255)
    note over ER,F: Restoring experiment on the Frontend <br>from the Director's experiment representation
    F->>+D: Restore experiment by name
    D->>ER: Gets required data
    note over ER,D: The Registry may also return <br>the experiment by its identifier
    D->>-F: Response with model structure and the plan
  end


  F->>+D: Requests training artifacts
  D->>ER: Gets training artifacts
  D->>-F: Respond

  F->>+D: Requests removing the Experiment entry
  D->>ER: Removes Experiment from registry

  deactivate ER
  deactivate ER

  D->>-F: Acknowledges
  
    

Communications Altering or Requesting Experiment-Related Information