OpenStack Swift Object Store File System - Beta - Import

Bridge Specifications

Vendor	OpenStack
Tool Name	Swift Object Store File System
Tool Version	1.0
Tool Web Site	https://www.openstack.org/software/releases/queens/components/swift
Supported Methodology	[File System] Multi-Model, Data Store (NoSQL / Hierarchical) via REST API
Data Profiling
Incremental Harvesting
Multi-Model Harvesting
Remote Repository Browsing for Model Selection

SPECIFICATIONS
Tool: OpenStack / Swift Object Store File System version 1.0 via REST API
See https://www.openstack.org/software/releases/queens/components/swift
Metadata: [File System] Multi-Model, Data Store (NoSQL / Hierarchical)
Component: OpenStackSwift version 11.2.0

OVERVIEW
This import bridge crawls a data lake implemented on a OpenStack Swift to detect (reverse engineer) metadata from all the data files (for data catalog purpose).

REQUIREMENTS

SUPPORTED FILES

This import bridge supports the following file formats:
- Delimited (Flat) files such as CSV (see details below)
- Positional (Fixed Length) files typically from mainframe (see details below)
- COBOL COPYBOOK files typically from mainframe (see details below)
- Open Office Excel XML .XSLX (see details below)
- W3C XML
- JSON (JavaScript Object Notation)
- Apache Avro
- Apache Parquet
- Apache ORC

as well as the compressed versions of the above formats:
- ZIP (as a compression format, not as archive format)
- BZIP
- GZIP
- LZ4
- Snappy (as standard Snappy format, not as Hadoop native Snappy format)

DELIMITED FILES

This import bridge detects (reverse engineer) the metadata from a data file of type Delimited File (also known as Flat File).
The detection of such Delimited File is not based on file extensions (such as .CSV, .PSV) but rather by sampling the file content.

The import bridge can detect a header row, and use it to create the field name, otherwise generic field names are created.

The import bridge samples up to 1000 rows in order to automatically detect the field separators which by default include:
', (comma)', '; (semicolon)', ': (colon)', '\t (tab)', '| (pipe)', '0x1 (ctrl+A)'
More separators can be added in the auto detection process (including double characters), see the Miscellaneous parameter.

During the sampling, the import bridge also detects the file data types, such as DATE, NUMBER, STRING.

POSITIONAL FILES

This import bridge creates metadata for data files of type Positional File (also known as Fixed Length File).
Such metadata cannot be automatically detected (reverse engineered) by sampling the data files (e.g. customers.dat or even just customers with no extension).
Therefore, this import bridge imports a 'Positional File Definition' file which must be with extension .positional_file_definition format file
(e.g. customers.dat.positional_file_definition format file will create the metadata of a file named file customers with the fields defined inside)
This is the equivalent of a RDBMS DDL for positional files. With such a long extension, this data definition file can coexist with the actual data files in the each file system directory containing them.

The 'Positional File Definition' file format is defined as follows:
- Format file must start with the following header:
column name, position, width, data type, comment
- All positions must be unique and greater than or equal to 1.
a,1
b,5
- The file format is invalid when some columns have positions and others don't.
a,1
b,
c,5
- When all columns do not have positions but have widths the application assumes that columns are ordered and calculates positions based on widths.
a,,4 -> a,1,4
b,,25 -> b,5,25
- When the position is present the application uses widths for documentation only.
a,1,4
b,5,25
- Types and comments are used as documentation only.
a,1,4,int
b,5,25,char[25],identifier

COBOL COPYBOOK FILES

This import bridge can only import the COBOL COPYBOOK files (which contain the data definitions), therefore does not detect (reverse engineer) metadata from actual COBOL data files.
The detection of such COBOL COPYBOOK file is not based on file extensions (such as .CPY) but rather by sampling the file content.

This bridge creates a 'Physical Hierarchical Model' which reflects a truly flat, byte-position defined, record structure, which is useful for stitching to the DI/ETL processes. Therefore, the physical model has all the physical elements required to define a flat record, which is ONE table with all the elements (including multiple columns for OCCURS elements when the proper import bridge parameter is set).

Note that this import bridge does not currently support the COPY verb, and reports a parsing error at the line and position at which the COPY statement begins. In order to import Copybooks with the Copy Statement, create an expanded Copybook file with the included sections already in place (replacing the COPY verb). Most COBOL compilers have the option to output only the preprocessed Copybooks with the COPY and REPLACE statements expanded.

FREQUENTLY ASKED QUESTIONS
Q: Why is the default start column '6' (six) and the default end column '72' (seventy-two)?
A: The import bridge parser counts columns starting at 0 (zero), rather than 1 (one). Thus, the defaults leave the standard first six columns for line numbers, next column for comment indicators, and last 8 columns (out of 80) for additional line comment information.

EXCEL (XLSX) FILES

This import bridge detects (reverse engineer) the metadata from a data file of type Excel XML format (XLSX).
The detection of such Excel file is based on file extension .XLSX.

The import bridge can detect a header row, and use it to create the field name, otherwise generic field names are created.

The import bridge samples up to 1000 rows to detect the file data types, such as DATE, NUMBER, STRING.

If an Excel file has multiple sheets, each sheet is imported as the equivalent of a file/table with the same sheet name.

The import bridge uses the machine's local to read files and allows you to specify the character set encoding files use.

LIMITATIONS
Refer to the current general known limitations at https://metaintegration.com/Products/MIMB/Help/#!Documents/mimbknownlimitations.html

SUPPORT
Provide a troubleshooting package with:
- the debug log (can be set in the UI or in conf/conf.properties with MIR_LOG_LEVEL=6)
- the metadata backup if available (can be set in the Miscellaneous parameter with -backup option, although this common option is not implemented on all bridges for technical reasons).

Bridge Parameters

Bridge Mapping