legend-engine

Execution engine for Legend. It provides:

• A Pure parser and compiler.
• An execution engine, generating and/or executing execution plans when provided with a Pure function, a Mapping and a Runtime.
• Access point for model transformers written using the Pure language (soon to come).

Development setup

• This application uses Maven 3.6+ and JDK 11. Run mvn install to compile.
• To start the server, please use the Main class org.finos.legend.engine.server.Server with the parameters: server legend-engine-config/legend-engine-server/legend-engine-server-http-server/src/test/resources/org/finos/legend/engine/server/test/userTestConfig.json.
• You can test by trying http://127.0.0.1:6300 on a web browser. The swagger page can be accessed at http://127.0.0.1:6300/api/swagger

Given the size of the project, developers should consider using parallelism to speed up build times, given enough RAM is provided. In IntelliJ IDEA, this can be done by setting Thread Count (in Preferences > Build, Execution, Deployment > Build Tools > Maven) and Shared build process heap size (Mbytes) (in Preferences > Build, Execution, Deployment > Compiler > Java Compiler). For example, setting Thread Count to 4 and Shared build process heap size (Mbytes) to 30000 can significantly reduce build times, you need to fine-tune this to match your machine's specs.

⚠️ It's also important to disable the Clear output directory on rebuild in Preferences > Build, Execution, Deployment > Complier as this removes generated resources needed to run the servers from the IDE.

Running memSQL tests on Mac

• Follow these instructions: https://github.com/singlestore-labs/singlestoredb-dev-image?tab=readme-ov-file#how-to-run-the-docker-image-on-apple-silicon-m1m2-chips

Starting Pure IDE

If you're making changes to the Pure codebase, it's highly recommended that you also spin up our Pure IDE application:

• To start the server, please use the Main class org.finos.legend.engine.ide.PureIDELight with the parameters: server legend-engine-pure/legend-engine-pure-ide/legend-engine-pure-ide-light-http-server/src/main/resources/ideLightConfig.json.
• You can now access the IDE at http://127.0.0.1:9200/ide in a web browser.

Debugging Pure Code

To debug your Pure code, you need to use the meta::pure::ide::debug() function to create breakpoints.

When you execute the go function using F9, the execution will be paused at the breakpoint, and a summary will be printed.

This summary include the current stack (for easy navigation to the current breakpoint point) and the variables accessible on such breakpoint.

Once in a breakpoint, using the Pure IDE terminal, you can take certain debugging actions:

• debug or debug summary: print the aforementioned summary.
• debug <pure expression>: evaluate the given expression. All variables on the current breakpoint are available.
  • ie. debug $f->map(x | $x->type()): introspect variable f and apply some functions to it.
• debug abort: stop the current execution. Pressing F9 after an abort command will start the execution from the beginning (ie. from the go function)

To resume the execution to next breakpoint or to completion, just press F9 again.

Caveats:

• Editing the code while on a breakpoint will lead to evaluation errors. You need to complete or abort current execution to pick new changes.
• Print commands within the debug expressions won't show on console. Avoid the print and evaluate to a string value instead.

Roadmap

Visit our roadmap to know more about the upcoming features.

Contributing

Visit Legend Contribution Guide to learn how to contribute to Legend.

License

Copyright 2020 Goldman Sachs

Distributed under the Apache License, Version 2.0.

SPDX-License-Identifier: Apache-2.0