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Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
Toolkits
A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
Toolkits
Toolkit com.teracloud.streams.crossdcfailover 2.0.0
Application and environment requirements

Welcome
Learn about the core capabilities of Teracloud® Streams, its architecture, and key concepts.
Installing
Use this information to install, upgrade, and uninstall the Teracloud® Streams product.
Configuring
Create a basic or an enterprise domain which is a single point for configuring and managing common resources, security, and instances.
Administering
Administer the product by using the Teracloud® Streams graphical user interface, APIs, or the streamtool command-line interface.
Developing
Develop stream applications with the Streams Processing Language (SPL), Java, and Python.
Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
- APIs
  Application programming interfaces (APIs) provide functions that simplify applications development.
- Job configuration overlays
  You can specify or change configuration parameters when you use the submitjob or updateoperators operations. The settings control submission constraints, host constraints and locations, and operator status. Parameters are captured and updated in the configuration JSON file. When you change the values in the job configuration overlay file, the changes override any previously set values.
- Commands
  Teracloud® Streams provides a number of commands you use to perform tasks.
- Operator model
  An operator model is an XML document that describes the basic properties of a primitive operator.
- Streams Processing Language (SPL)
  Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
- Toolkits
  A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
  - Specialized toolkit requirements and restrictions
    Several of the specialized toolkits require RPMs that are not required by the Teracloud® Streams product. There are also toolkit restrictions on some platforms.
  - Toolkits
- SPLDOC markup
  You can use SPLDOC markup in the descriptions associated with the SPL artifacts in a toolkit. The spl-make-doc command generates HTML documentation from the marked up artifacts.
Glossary
Use this glossary to find terms and definitions for Teracloud® Streams.

Application and environment requirements

The following requirements should be reveiwed before developing a Streams application with the toolkit.

Any Streams application interested in using this toolkit should be prepared to invoke an SPL composite operator available in this toolkit and complete the input and output stream requirements of that composite operator. Application logic will have to call one or more native functions provided by this toolkit in order to perform the periodic data replication between data centers. In summary, application logic will be required to properly integrate with the composite operator provided by this toolkit.
When building applications with this toolkit, the inetserver toolkit must be available in the STREAMS_SPLPATH environment variable or specified with the -t option on the sc command.
In order for this toolkit to work properly, there should be network connectivity available between the two data centers. This toolkit will open HTTP connections between the two data centers with a user specified HTTP port number. So, there should be no firewall blocking this HTTP communication in both data centers.
If the cross DC data replication option is enabled, then the replicated data will be stored either in a relational database table or in a file system at both the data centers. This will require access to a relational database via JDBC from the Streams application machine(s) or read/write access to a shared/mapped drive either via NFS or NAS that can be accessed from all the Streams application machines in a given data center. Depending on the size of the in-memory state held by the application logic, the total size of the database or the shared drive in each data center should be planned ahead of time and provisioned properly.