Snapd REST API error responses

doc
1

When Using the snapd REST API, requests sent to the snapd REST API can return both standard HTTP error responses, and a snapd-specific error kind, in the body of the response. These are detailed below.

Status codes

The REST API returns standard HTTP error response status ranges and codes, such as 4xx for client errors and 5xx for server side issues, with descriptions. For example:

Code Status Example description
400 Bad request Snap is already installed
400 Bad request Snap is not installed / unknown action
401 Unauthorized Access denied. Login required.
403 Forbidden Access denied. Login required.
404 Not found Channel not available / snap does not exist
409 Conflict Snap snap has change-kind change in progress
500 Internal server error many unexpected errors

Conflict errors (409) may be temporary. They are often returned when a new operation on an entity cannot be initiated because a previous operation is still in progress. This might cause new operations on one or more snaps to see errors with the snap-change-conflict error kind, for example. When a conflicting operation completes, new operations may be retried and should later succeed, assuming the completed operation didn’t break any dependent state for the new operation.

Error kinds

The following error kind values provide extra context on an error response:

  • app-not-found: the requested app couldn’t be found.
  • assertion-not-found: assertion can not be found.
  • auth-cancelled: authentication was cancelled by the user.
  • bad-query: a bad query was provided.
  • dns-failure: DNS not responding.
  • insufficient-disk-space: returned when disk space awareness is enabled and either an install, remove or refresh operation fails due to insufficient free disk space. The error value is an object that contains snap-names, an array of affected snaps, and a change-kind string with the failed operation.
  • interfaces-unchanged: the requested interfaces’ operation would have no effect.
  • invalid-auth-data: the authentication data provided failed to validate (e.g. a malformed email address). The value of the error is an object with a key per failed field and a list of the failures on each field.
  • login-required: the requested operation cannot be performed without an authenticated user. This is the kind of any other 401 Unauthorized response.
  • network-timeout: a timeout occurred during the request.
  • option-not-found: the given configuration option does not exist.
  • password-policy: provided password doesn’t meet system policy.
  • snap-already-installed: the requested snap is already installed.
  • snap-architecture-not-available: no snap revision on specified architecture. Value has the same format as for snap-channel-not-available.
  • snap-change-conflict: the requested operation would conflict with currently ongoing change. This is a temporary error. The error value is an object with optional fields snap-name, change-kind of the ongoing change.
  • snap-channel-not-available: no snap revision on specified channel. The value of the error is a rich object with requested snap-name, action, channel, architecture, and actually available releases as list of {"architecture":... , "channel": ...} objects.
  • snap-local: cannot perform operation on local snap.
  • snap-needs-classic: the requested snap needs classic confinement to be installed.
  • snap-needs-classic-system: the requested snap can’t be installed on the current non-classic system.
  • snap-needs-devmode: the requested snap needs devmode to be installed.
  • snap-no-update-available: the requested snap does not have an update available.
  • snap-not-a-snap: the given snap or directory does not look like a snap.
  • snap-not-classic: snap not compatible with classic mode.
  • snap-not-found: the requested snap couldn’t be found.
  • snap-not-installed: the requested snap is not installed.
  • snap-revision-not-available: no snap revision available as specified.
  • two-factor-failed: the OTP provided wasn’t recognised.
  • two-factor-required: the client needs to retry the login command including an OTP.
  • unsuccessful: snapctl command was unsuccessful.
  • validation-set-not-found: the validation set cannot be found.
  • apparmor-prompting-not-running: AppArmor prompting is not running.
  • interfaces-requests-*: errors specific to AppArmor prompting client interactions (e.g., so no such rule, rule already exists, etc).

Maintenance error kinds

These are used only inside the maintenance field of responses.

  • daemon-restart: daemon is restarting.
  • system-restart: system is restarting.