Module: OKF::MCP::Backend

Defined in:
lib/okf/mcp/backend.rb

Overview

The seam between the shell and the optional okf-sqlite3 engine. One require answers both "is it installed?" and "does the native extension load?" — a broken sqlite3 build degrades to the memory backend instead of crashing the server, silently except in the boot line and list_bundles.backend. Feature detection, not version pinning: the engine only has to answer the duck type below, so the gems release independently. Backends speak symbol-keyed rows in the kernel's catalog and search shapes; score and snippet are optional extras.

Constant Summary collapse

ENGINE_METHODS = 
%i[refresh search catalog capabilities].freeze

Class Method Summary collapse

Class Method Details

.build_engine ⇒ Object

Both ways the optional engine can fail are on this side of the seam, so the one rescue above covers both: the require (absent gem, native extension that will not load) and the construction (a connection it cannot open, a schema check, a constant renamed out from under us). Catching only LoadError left the second half fatal, which is exactly what "degrades instead of crashing the server" promises it is not.



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# File 'lib/okf/mcp/backend.rb', line 29

def self.build_engine
  require "okf/sqlite3"
  OKF::Sqlite3::Backend.new
end

.detect ⇒ Object 



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# File 'lib/okf/mcp/backend.rb', line 16

def self.detect
  engine = build_engine
  suitable?(engine) ? engine : MemoryBackend.new
rescue LoadError, StandardError
  MemoryBackend.new
end

.suitable?(engine) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/okf/mcp/backend.rb', line 34

def self.suitable?(engine)
  ENGINE_METHODS.all? { |name| engine.respond_to?(name) }
end