Pulls messages from the server. Returns an empty list if there are no messages available in the backlog. The server may return UNAVAILABLE if there are too many concurrent pull requests pending for the given subscription.

Scopes

You will need authorization for at least one of the following scopes to make a valid call:

  • https://www.googleapis.com/auth/cloud-platform
  • https://www.googleapis.com/auth/pubsub

If unset, the scope for this method defaults to https://www.googleapis.com/auth/cloud-platform. You can set the scope for this method like this: pubsub1-beta2 --scope <scope> projects subscriptions-pull ...

Required Scalar Argument

  • <subscription> (string)
    • The subscription from which messages should be pulled.

Required Request Value

The request value is a data-structure with various fields. Each field may be a simple scalar or another data-structure. In the latter case it is advised to set the field-cursor to the data-structure's field to specify values more concisely.

For example, a structure like this:

PullRequest:
  max-messages: integer
  return-immediately: boolean

can be set completely with the following arguments which are assumed to be executed in the given order. Note how the cursor position is adjusted to the respective structures, allowing simple field names to be used most of the time.

  • -r . max-messages=89
    • The maximum number of messages returned for this request. The Pub/Sub system may return fewer than the number specified.
  • return-immediately=false
    • Optional. If this is specified as true the system will respond immediately even if it is not able to return a message in the Pull response. Otherwise the system is allowed to wait until at least one message is available rather than returning no messages. The client may cancel the request if it does not wish to wait any longer for the response. Warning: setting this field to true is discouraged because it adversely impacts the performance of Pull operations. We recommend that users do not set this field.

About Cursors

The cursor position is key to comfortably set complex nested structures. The following rules apply:

  • The cursor position is always set relative to the current one, unless the field name starts with the . character. Fields can be nested such as in -r f.s.o .
  • The cursor position is set relative to the top-level structure if it starts with ., e.g. -r .s.s
  • You can also set nested fields without setting the cursor explicitly. For example, to set a value relative to the current cursor position, you would specify -r struct.sub_struct=bar.
  • You can move the cursor one level up by using ... Each additional . moves it up one additional level. E.g. ... would go three levels up.

Optional Output Flags

The method's return value a JSON encoded structure, which will be written to standard output by default.

  • -o out
    • out specifies the destination to which to write the server's result to. It will be a JSON-encoded structure. The destination may be - to indicate standard output, or a filepath that is to contain the received bytes. If unset, it defaults to standard output.

Optional General Properties

The following properties can configure any call, and are not specific to this method.

  • -p $-xgafv=string

    • V1 error format.

  • -p access-token=string

    • OAuth access token.

  • -p alt=string

    • Data format for response.

  • -p callback=string

    • JSONP

  • -p fields=string

    • Selector specifying which fields to include in a partial response.

  • -p key=string

    • API key. Your API key identifies your project and provides you with API access, quota, and reports. Required unless you provide an OAuth 2.0 token.

  • -p oauth-token=string

    • OAuth 2.0 token for the current user.

  • -p pretty-print=boolean

    • Returns response with indentations and line breaks.

  • -p quota-user=string

    • Available to use for quota purposes for server-side applications. Can be any arbitrary string assigned to a user, but should not exceed 40 characters.

  • -p upload-type=string

    • Legacy upload protocol for media (e.g. "media", "multipart").

  • -p upload-protocol=string

    • Upload protocol for media (e.g. "raw", "multipart").