Looker Server - Technical Preview - Import - Cloud

Talend Cloud Data Catalog Bridges

author
Talend Documentation Team
EnrichVersion
Cloud
EnrichProdName
Talend Cloud
EnrichPlatform
Talend Data Catalog

Bridge Specifications

Vendor Looker
Tool Name Looker
Tool Version 7.2
Tool Web Site https://www.looker.com/
Supported Methodology [Business Intelligence] Multi-Model, BI Design (RDBMS Source, Dimensional Target, Transformation Lineage, Expression Parsing), BI Report (Relational Source, Dimensional Source, Report Structure) via REST API
Data Profiling
Remote Repository Browsing for Model Selection
Multi-Model Harvesting
Incremental Harvesting

SPECIFICATIONS
Tool: Looker / Looker version 7.2 via REST API
See https://www.looker.com/
Metadata: [Business Intelligence] Multi-Model, BI Design (RDBMS Source, Dimensional Target, Transformation Lineage, Expression Parsing), BI Report (Relational Source, Dimensional Source, Report Structure)
Component: Looker version 11.0.0

OVERVIEW
This bridge imports metadata from a Looker server, including database connections, LookML Models, and associated reports (Looks and Dashboards).

REQUIREMENTS
Looker API3 key is required in order to login and use the Looker Restful API.
Please use the Looker Admin console to configure an API3 key on a user account.
The API3 key consists in a public client_id and a private client_secret (OAuth2 authentication pattern).
* Select a user in the 'Users' section of the 'Admin' panel
* In the section 'API3 Keys' choose 'Edit Keys'
The 'Client ID' and 'Client Secret' values are displayed https://docs.looker.com/reference/api-and-integration/api-auth
https://docs.looker.com/admin-options/settings/users#api3_keys
You can test that the API key is configured correctly by performing a login on this page:
https://server:19999/api-docs/index.html
Looker versions 3.4+ expose the Restful API on default port is 19999.
Please use the Looker Admin console to check your API port.
https://docs.looker.com/reference/api-and-integration/api-troubleshooting

You may use this URL in a web browser, to check the API availability and version(s) number(s):
https://server:19999/versions

FREQUENTLY ASKED QUESTIONS
n/a

LIMITATIONS
Refer to the current general known limitations at http://metaintegration.com/Products/MIMB/MIMBKnownLimitations.html or bundled in Documentation/ReadMe/MIMBKnownLimitations.html

SUPPORT
Provide a trouble shooting 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 option -backup)

Q: How do I provide metadata to the support team to reproduce an issue?
A: Configure the bridge parameter 'Incremental import=False' and configure the bridge 'Miscellaneous' parameter to save metadata as files into a local directory.
Compress the resulting files in a ZIP archive and send to the support team.


Bridge Parameters

Parameter Name Description Type Values Default Scope
Server API URL Enter the Looker API URL here.
The default port for API requests is port 19999.
All Looker API endpoints require an HTTPS connection.
STRING   https://localhost:19999/ Mandatory
Login User Enter the username which the bridge will use to log in. Be sure this user name has necessary permissions to access the objects you wish to import.
This corresponds to the Client ID for an OAuth authentication method.
STRING     Mandatory
Login Password Enter the password associated with the username which the bridge will use to log in.
This corresponds to the Client secret for an OAuth authentication method.
PASSWORD     Mandatory
Project filter This option is used to select looks and dashboards by their parent project.

You can specify here multiple projects, separated by semicolon (;) character.
REPOSITORY_SUBSET      
Incremental import Incremental import only extracts what has changed since the last import. The initial full metadata harvesting (model import) of a very large source system can take a long time. However the extracted metadata are organized as a multi-model, where each model is a unit of change (e.g. Schema of a RDBMS server, or report of BI server). Subsequent model imports are dramatically faster than the initial import as this bridge will automatically try to detect changes in the source system, in order to only process the modified, added or deleted models and reuse all unchanged metadata from the model cache. Note however that the detection of change is more or less efficient depending on the sources system: e.g. BI servers can quickly provide the list of new, modified or deleted reports, but not all data stores offer a schema level change detection.

'True'
Import only the changes made since the last import

'False'
import all metadata. This option is required after upgrading the bridge in particular to take full advantage of any additional metadata coverage.

For debugging purpose, the option -cache.clear of the Miscellaneous parameter can be used to clear one model from the cache which is located (by default) in: $HOME/data/MIMB/cache/<BridgeId>/<ModelId>
BOOLEAN
False
True
True  
Multiple threads Number of worker threads to harvest metadata asynchronously.

- Leave the parameter blank to have the bridge compute the value, between 1 and 6, based on JVM architecture and number of available CPU cores.

- Specify a numeric value greater or equal to 1 to provide the actual number of threads.
If the value specified is invalid, a warning will be issued and 1 will be used instead.
If you experience out of memory conditions when harvesting metadata asynchronously, experiment with smaller numbers.
If your machine has a lot of available memory (e.g. 10 Gb or more), you can try larger numbers when harvesting many documents at once.
Note that setting the number too high can actually decrease the performance due to resource contention.
NUMERIC      
Offline metadata directory In order to facilitate testing and reproducing Looker metadata environment, when that environment is not installed locally, this parameter allows importing metadata from files previously downloaded from the Looker server. Specify in this parameter the directory path where the downloaded files are located. No connection to the Looker server is needed in this case, the usual connection parameters are ignored. DIRECTORY      
Miscellaneous INTRODUCTION
Specify miscellaneous options starting with a dash and optionally followed by parameters, e.g.
-connection.cast MyDatabase1="SQL Server"
Some options can be used multiple times if applicable, e.g.
-connection.rename NewConnection1=OldConnection1 -connection.rename NewConnection2=OldConnection2;
As the list of options can become a long string, it is possible to load it from a file which must be located in ${MODEL_BRIDGE_HOME}\data\MIMB\parameters and have the extension .txt. In such case, all options must be defined within that file as the only value of this parameter, e.g.
ETL/Miscellaneous.txt

JAVA ENVIRONMENT OPTIONS
-m <Java Memory's maximum size>
1G by default on 64bits JRE or as set in conf/conf.properties, e.g.
-m 8G
-m 8000M

-j <Java Runtime Environment command line options>
This option must be the last one in the Miscellaneous parameter as all the text after -j is passed "as is" to the JRE, e.g.
-j -Dname=value -Xms1G
The following option must be set when a proxy is used to access internet (this is critical to access https://repo.maven.apache.org/maven2/ (and exceptionally a few other tool sites) in order to download the necessary third party software libraries.
-j -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttps.proxyHost=127.0.0.1 -Dhttps.proxyPort=3128 -Dhttp.proxyUser=user -Dhttp.proxyPassword=pass -Dhttps.proxyUser=user -Dhttps.proxyPassword=pass

-jre <Java Runtime Environment full path name>
It can be an absolute path to javaw.exe on Windows or a link/script path on Linux, e.g.
-jre "c:\Program Files\Java\jre1.8.0_211\bin\javaw.exe"

-v <Environment variable value>
None by default, e.g.
-v var1=value1 -v var2="value2 with spaces"

MODEL IMPORT OPTIONS
-model.name <model name>
Override the model name, e.g.
-model.name "My Model Name"

-prescript <script name>
The script must be located in the bin directory, and have .bat or .sh extension.
The script path must not include any parent directory symbol (..).
The script should return exit code 0 to indicate success, or another value to indicate failure.
For example:
-prescript "script.bat arg1 arg2"

-cache.clear
Clears the cache before the import, and therefore will run a full import without incremental harvesting.
Warning: this is a system option managed by the application calling the bridge and should not be set by users.

-backup <directory>
Full path of an empty directory to save the metadata input files for further troubleshooting.

DATA CONNECTION OPTIONS
Data Connections are produced by the import bridges typically from ETL/DI and BI tools to refer to the source and target data stores they use. These data connections are then used by metadata management tools to connect them (metadata stitching) to their actual data stores (e.g. databases, file system, etc.) in order to produce the full end to end data flow lineage and impact analysis. The name of each data connection is unique by import model. The data connection names used within DI/BI design tools are used when possible, otherwise connection names are generated to be short but meaningful such as the database / schema name, the file system path, or Uniform Resource Identifier (URI). The following options allows to manipulate connections. These options replaces the legacy options -c, -cd, and -cs.

-connection.cast ConnectionName=ConnectionType
Casts a generic database connection (e.g. ODBC/JDBC) to a precise database type (e.g. ORACLE) for SQL Parsing, e.g.
-connection.cast "My Database"="SQL SERVER".
The list of supported data store connection types includes:
ACCESS
CASSANDRA
DB2
DENODO
HIVE
MYSQL
NETEZZA
ORACLE
POSTGRESQL
PRESTO
REDSHIFT
SALESFORCE
SAP HANA
SNOWFLAKE
SQL SERVER
SYBASE
TERADATA
VECTORWISE
VERTICA

-connection.rename OldConnection=NewConnection
Renames an existing connection to a new name, e.g.
-connection.rename OldConnectionName=NewConnectionName
Multiple existing database connections can be renamed and merged into one new database connection, e.g.
-connection.rename MySchema1=MyDatabase -connection.rename MySchema2=MyDatabase

-connection.split oldConnection.Schema1=newConnection
Splits a database connection into one or multiple database connections.
A single database connection can be split into one connection per schema, e.g.
-connection.split MyDatabase
All database connections can be split into one connection per schema, e.g.
-connection.split *
A database connection can be explicitly split creating a new database connection by appending a schema name to a database, e.g.
-connection.split MyDatabase.schema1=MySchema1

-connection.map DestinationPath=SourcePath
Maps a source path to destination path. This is useful for file system connections when different paths points to the same object (directory or file).
On Hadoop, a process can write into a CSV file specified with the HDFS full path, but another process reads from a HIVE table implemented (external) by the same file specified using a relative path with default file name and extension, e.g.
-connection.map hdfs://host:8020/users/user1/folder/file.csv=/user1/folder
On Linux, a given directory (or file) like /data can be referred to by multiple symbolic links like /users/john and /users/paul, e.g.
-connection.map /users/John=/data -connection.map /users/paul=/data
On Windows, a given directory like C:\data can be referred to by multiple network drives like M: and N:, e.g.
-connection.map M:\=C:\data -connection.map N:\=C:\data

-pppd
Create the connections and connection data sets in DI/ETL design models. This feature should only be used when intending to export to another DI/ETL tool.
STRING      

 

Bridge Mapping

Mapping information is not available