streamtool getnsentry

Usage

getnsentry [-d,--domain-id <did>] [-i,--instance-id <instance>] [--fmt <format-spec>] [--xheaders] [--scope <scope-pattern>] [-U,--User <user>] [-h,--help] [--trace <level>] [-v,--verbose <level>] [--zkconnect {<host>:<port>},... | --embeddedzk] <name-pattern>

The streamtool getnsentry command finds an application entry that is stored in ZooKeeper and prints the value.

Authority

You do not need any authority to run this command.

Description

Streams uses ZooKeeper to store service references for the applications that are running in an instance. Streams also uses ZooKeeper to register symbolic names that can be looked up by external applications or users.

If there are no instances with the specified name pattern, the command returns a nonzero exit code.

Options

-d,--domain-id <did>
Specifies the domain identifier.

If you do not specify this option, Streams uses the domain name that is set in the STREAMS_DOMAIN_ID environment variable. By default, that domain name is StreamsDomain. If you are using the interactive streamtool interface, it uses the name of the active domain for the current streamtool session or else it prompts you for the domain name.

The active domain for the current streamtool session is set every time that you successfully run a streamtool command with a -d or --domain-id option. Alternatively, you can run the streamtool domain command in the interactive interface.

--embeddedzk

Specifies to use the embedded copy of ZooKeeper. This option is not supported within the interactive streamtool interface.

If you are not using the interactive streamtool interface and you do not specify either this option or the --zkconnect option, Streams uses the ZooKeeper connection that is associated with the active domain or the domain that is specified in the --domain-id option. Streams determines which connection maps to the domain by using cached information about the domains. In this scenario, if the domain identifier is not unique in the Streams configuration cache, the command fails.

--fmt <format-spec>
Specifies the presentation format. The command supports the following values:
  • %Mf: Multiline record format. One line per field.
  • %Nf: Name prefixed field table format. One line per name service entry.
  • %Tf: Standard table format, which is the default. One line per name service entry.
-h,--help
Specifies to show the command syntax.
-i,--instance-id <instance>
Specifies the instance identifier.

If you do not specify this option, Streams uses the instance identifier that is set in the STREAMS_INSTANCE_ID environment variable. By default, that instance identifier is StreamsInstance. If you are using the interactive streamtool interface, it tries to use an instance ID that you specified in a previous command. If no such value is found, the command uses the STREAMS_INSTANCE_ID environment variable. Alternatively, you can run the streamtool instance command in the interactive interface.

--scope <scope-pattern>
Specifies the application scope pattern. By default, the command searches all scopes. The scope can include wildcards by using * to match any characters.
--trace <level>
Specifies the trace setting. The following valid levels are listed in order of increasing verbosity, which is to say that the first level in the list generates the least amount of information:
  • off
  • error
  • warn
  • info
  • debug
  • trace
The default value is off.
-U,--User <user>
Specifies an Streams user ID that has authority to run the command.
-v,--verbose <level>
Specifies to provide more detailed command output. The verbosity level can be 0-3, where 0 disables detailed reporting and each increment provides more detailed output.
--xheaders
Specifies to exclude headings from the report.
--zkconnect <{<host>:<port>},...>

The name of one or more host and port pairs that specify the configured ZooKeeper servers. This option is not supported within the interactive streamtool interface.

If you are not using the interactive streamtool interface and you do not specify this option, Streams tries to use:

  1. The --embeddedzk option
  2. The value from the STREAMS_ZKCONNECT environment variable
  3. A ZooKeeper connection string that is derived from cached information about the current domain.

Arguments

name-pattern
Specifies the name pattern to search for. The name patterns can include wildcards by using * to match any characters.