State machine orchestrating the execution of a commit operation.

The processor drives a Gno.Changeset through a multi-phase pipeline — pre-commit, transaction, post-commit — with automatic rollback on failure. At each state transition, the configured Gno.CommitMiddleware pipeline is invoked, and the actual step logic is delegated to the Gno.CommitOperation.Type.

Phases

• Pre-commit: Initializes the changeset from input, computes the Gno.EffectiveChangeset, and prepares metadata (e.g. the Gno.Commit).
• Transaction: Starts a SPARQL transaction, applies the changes, and commits the transaction. Failures in this phase trigger a rollback.
• Post-commit: Runs finalization logic. Failures here do not roll back (the transaction is already committed).

Struct Fields

• service - the Gno.Service this processor operates on
• state - the current state/0 in the state machine
• input - the raw input passed to execute/3
• input_options - options passed to execute/3
• middlewares - the list of Gno.CommitMiddleware instances
• changeset - the Gno.Changeset created from the input
• effective_changeset - the Gno.EffectiveChangeset computed during preparation
• sparql_update - the Gno.Store.SPARQL.Operation built from the effective changeset
• additional_changes - extra changes for specific graphs, keyed by graph name
• metadata - an RDF.Graph accumulating commit metadata (PROV vocabulary)
• assigns - a free-form map for sharing state between middlewares
• errors - accumulated errors during processing

State Machine

stateDiagram-v2
  [*] --> initializing : init

  %% Pre-Commit Phase
  initializing --> initialized : success
  initializing --> middleware_rollback: fail
  initialized --> preparing : success -> prepare
  initialized --> middleware_rollback: fail
  preparing --> prepared: success
  preparing --> middleware_rollback: fail
  prepared --> starting_transaction: success -> start_transaction
  prepared --> middleware_rollback: fail

  %% Transaction Phase
  starting_transaction --> transaction_started: success
  starting_transaction --> middleware_rollback: fail
  transaction_started --> applying_changes: success -> apply_changes
  transaction_started --> middleware_rollback: fail
  applying_changes --> changes_applied: success
  applying_changes --> middleware_rollback: fail
  changes_applied --> ending_transaction: success -> end_transaction
  changes_applied --> rollback: fail
  ending_transaction --> transaction_ended: success
  ending_transaction --> rollback: fail

  %% Post-Commit Phase
  transaction_ended --> executing_post_commit: success -> post_commit
  transaction_ended --> rollback: fail
  executing_post_commit --> completed: success
  executing_post_commit --> error: fail
  completed --> [*]

  %% Rollback Phase
  rollback --> middleware_rollback: success
  rollback --> critical_error: fail
  middleware_rollback --> error: success
  middleware_rollback --> critical_error: fail

  %% Error States
  error --> [*]
  critical_error --> [*]

  state pre-commit {
      initializing
      initialized
      preparing
      prepared
  }
  state commit-transaction {
      starting_transaction
      transaction_started
      applying_changes
      changes_applied
      ending_transaction
      transaction_ended
  }
  state post-commit {
      executing_post_commit
      completed
  }