Watches a specific variable and waits for a change in the variable's value. When there is a change, this method returns the new value or times out. If a variable is deleted while being watched, the variableState state is set to DELETED and the method returns the last known variable value. If you set the deadline for watching to a larger value than internal timeout (60 seconds), the current variable value is returned and the variableState will be VARIABLE_STATE_UNSPECIFIED. To learn more about creating a watcher, read the Watching a Variable for Changes documentation.

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/cloudruntimeconfig

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: runtimeconfig1-beta1 --scope <scope> projects configs-variables-watch ...

Required Scalar Argument

  • <name> (string)
    • The name of the variable to watch, in the format: projects/[PROJECT_ID]/configs/[CONFIG_NAME]

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:

WatchVariableRequest:
  newer-than: string

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 . newer-than=ipsum
    • If specified, checks the current timestamp of the variable and if the current timestamp is newer than newerThan timestamp, the method returns immediately. If not specified or the variable has an older timestamp, the watcher waits for a the value to change before returning.

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").