instructure/canvas-lms · error

No content importer registered for #

Error message

No content importer registered for #{context_type}

What it means

Canvas maintains a registry of content importers keyed by the importer class's item_class name (registered via ContentImporter.register). content_importer_for looks up the registry by context_type string and raises when no importer has been registered under that key, meaning the requested context type has no importer capable of handling the migration.

Solutions

  1. Check the exact context_type string passed and compare it to registered keys (Importers.content_importers or the register calls in app/models/importers/*.rb)
  2. Ensure the importer class for that context is defined and loaded before lookup (eager_load / require the file)
  3. If the context type genuinely isn't importable, guard the call site and handle the unsupported type instead of raising
  4. For plugin-provided importers, verify the plugin is installed and enabled on the shard/account

Example fix

// before
klass = Importers.content_importer_for(context_type)
// after
klass = Importers.content_importer_for(context_type) rescue nil
return render_error('unsupported content type') unless klass
Defensive patterns

Strategy: validation

Validate before calling

registered = Importers.content_importers rescue {}
raise 'unsupported context type' unless registered.key?(context_type)

Type guard

def importable_context?(context_type)
  Importers.content_importer_for(context_type)
rescue RuntimeError
  false
end

Try / catch

begin
  klass = Importers.content_importer_for(context_type)
rescue RuntimeError => e
  render json: { error: "no importer for #{context_type}" }, status: :bad_request
end

Prevention

When it happens

Trigger: Calling Importers.content_importer_for(context_type) with a context_type string that no importer registered — a typo, an unsupported context class, or the importer class never being loaded (e.g. in a context where plugin importers aren't required).

Common situations: Content migration requests targeting an account/course context whose importer plugin isn't installed; passing 'User' or another non-importable context; refactors renaming item_class so the registry key no longer matches the lookup string.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/005d10c033cf4415. Report an issue: GitHub.

Appendix: source

Thrown at app/models/importers.rb:28

# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.

module Importers
  def self.register_content_importer(klass)
    @content_importers ||= {}
    @content_importers[klass.item_class.to_s] = klass
  end

  def self.content_importer_for(context_type)
    klass = @content_importers&.[](context_type)
    raise "No content importer registered for #{context_type}" unless klass

    klass
  end

  def self.disable_live_events!
    ActiveRecord::Base.observers.disable LiveEventsObserver
    yield
  ensure
    enable_live_events!
  end

  def self.enable_live_events!
    ActiveRecord::Base.observers.enable LiveEventsObserver
  end

  class Importer
    class << self
      attr_accessor :item_class

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