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 |  |
| Incremental Harvesting |  |
| Multi-Model Harvesting | |
| Remote Repository Browsing for Model Selection | |
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 11.1.0
OVERVIEW
This import 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:port/api-docs/index.html
Looker versions 3.4+ expose the Restful API on default port 19999 or 443.
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:port/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
Looker models may use Derived Tables in order to cache and precompute data from the database.
The Looker API currently doesn't expose detailed DerivedTable metadata.
The Looker API has limited support for Views that are not included in Explores.
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 -backup option, although this common option is not implemented on all bridges for technical reasons).
Q: How do I provide metadata to the support team to reproduce an issue?
A: Configure the import bridge parameter 'Incremental import=False' and configure the import bridge 'Miscellaneous' parameter 'backup' 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 may be 19999 or 443. All Looker API endpoints require an HTTPS connection. |
STRING | https://localhost:19999/ | Mandatory | |||
| Login User | Enter the username which the import 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 import 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 model. You can specify here multiple model identifiers, 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 import 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 import 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 |
|
True | |||
| Multiple threads | Number of worker threads to harvest metadata asynchronously. - Leave the parameter blank to have the import 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 reproduction of issues with the Looker metadata environment that is not accessible locally, use this parameter to specify a location where the metadata files have previously been downloaded from a Looker server. Specify the directory path where the downloaded offline metadata files are located. No connection to the Looker server is needed in this case, the usual connection parameters are ignored. How to attain the required offline metadata files: 1. During the initial import specify the 'Miscellaneous' parameter 'backup'. 2. The offline folder mode should be used with the same Project(s) or a smaller subset than what was specified when creating the backup. 3. Following a succesful import, perform another import, and specify this parameter to point at the 'backup' directory created for the first import. That folder will be used as the source of the metadata for this secondary import. |
DIRECTORY | |||||
| Miscellaneous | INTRODUCTION Specify miscellaneous options starting with a dash and optionally followed by parameters, e.g. -connection.cast MyDatabase1="MICROSOFT 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 -java.memory <Java Memory's maximum size> (previously -m) 1G by default on 64bits JRE or as set in conf/conf.properties, e.g. -java.memory 8G -java.memory 8000M -java.parameters <Java Runtime Environment command line options> (previously -j) This option must be the last one in the Miscellaneous parameter as all the text after -java.parameters is passed "as is" to the JRE, e.g. -java.parameters -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. Note: The majority of proxies are concerned with encrypting (HTTPS) the outside (of the company) traffic and trust the inside traffic that can access proxy over HTTP. In this case, an HTTPS request reaches the proxy over HTTP where the proxy HTTPS-encrypts it. -java.parameters -java.parameters -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttp.proxyUser=user -Dhttp.proxyPassword=pass -java.executable <Java Runtime Environment full path name> (previously -jre) It can be an absolute path to javaw.exe on Windows or a link/script path on Linux, e.g. -java.executable "c:\Program Files\Java\jre\bin\javaw.exe" Some API based bridges (e.g. JDBC) may require a SSL / TLS based secure connection, no setup is needed when using an official certificate signed by a Certificate Authority (CA). However, when using a self signed certificate, then such a certificate needs to be imported in your java environment (before restarting your Java application) typically as follows: cd $JAVA_HOME/jre/lib/security mv jssecacerts jssecacerts.old $JAVA_HOME/bin/keytool -importkeystore -srckeystore {your_keystore} -keystore jssecacerts -environment.variable <name>=<value> (previously -v) None by default, e.g. -environment.variable 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> This option allows running a script before the bridge execution. The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), 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" -postscript <script name> This option allows running a script after successful execution of the bridge. The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), 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: -postscript "script.bat arg1 arg2" -cache.clear Clears the cache before the import, and therefore will run a full import without incremental harvesting. If the model was not changed and the -cache.clear parameter is not used (incremental harvesting), then a new version will not be created. If the model was not changed and the -cache.clear parameter is set (full source import instead of incremental), then a new version will be created. -backup <directory> This option allows to save the bridge input metadata for further troubleshooting. The provided <directory> must be empty. The primary use of this option is for data store import bridges, in particular JDBC based database import bridges. Note that this option is not operational on some bridges including: - File based import bridges (as such input files can be used instead) - DI/BI repository import bridges (as the tool's repository native backup can be used instead) - Some API based import bridges (e.g. COM based) for technical reasons. 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"="MICROSOFT SQL SERVER". The list of supported data store connection types includes: ACCESS APACHE CASSANDRA DB2/UDB DENODO GOOGLE BIGQUERY HIVE MYSQL NETEZZA ORACLE POSTGRESQL PRESTO REDSHIFT SALESFORCE SAP HANA SNOWFLAKE MICROSOFT SQL AZURE MICROSOFT SQL SERVER SYBASE SQL SERVER SYBASE AS ENTERPRISE TERADATA VECTORWISE HP 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 SourcePath=DestinationPath 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 /user1/folder=hdfs://host:8020/users/user1/folder/file.csv 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 /data=/users/John -connection.map /data=/users/paul On Windows, a given directory like C:\data can be referred to by multiple network drives like M: and N:, e.g. -connection.map C:\data=M:\ -connection.map C:\data=N:\ -connection.casesensitive ConnectionName Overrides the default case insensitive matching rules for the object identifiers inside the specified connection, provided the detected type of the data store by itself supports this configuration (e.g. Microsoft SQL Server, MySql etc.), e.g. -connection.casesensitive "My Database" -connection.level AggregationLevel Specifies the aggregation level for the external connections, e.g.-connection.level catalog The list of the supported values: server catalog schema (default) LOOKER OPTIONS -api.version <MajorInt>.<MinorInt> Specify the API version to use, such as 3.1 or 4.0 Version 4.0 is used by default. |
STRING |
Bridge Mapping
Mapping information is not available