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The following is a suggested workflow for new Pico developers. Related information is available in the following resources:

Programming involves a collection of tools, often referred to as the "tool chain" since they are used more or less in sequence. Here's a graphical representation of the tool chain for programming picos, noting each stage. We'll use this to organize the remainder of this document. Image Removed

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Develop

To develop KRL for picos, you can use Git (or another versioning tool) and your favorite editor. There are old plug ins for several popular editors. 

  1. Create a directory for your project 

    Code Block
    languagebash
    $ mkdir workflowmyproject
    $ cd workflowmyproject/


  2. Initialize the project directory as a Git repository

    Code Block
    languagebash
    $ git init


  3. Create a KRL ruleset as a file in the repository using your favorite editor. There may be a KRL plugin for your editor

Build

The build process for rulesets primarily involves editing them and then parsing them to ensure it is they are correctly formatted. The preferred way to do this ensure they parse is using a Git pre-commit hook. 

  1. Follow the directions in Setting Up a Git Pre-Commit Hook to Parse KRL to set up the KRL parser and ensure that KRL files are parsed before they are committed. 

  2. Add the file to the repository and commit it. 

    Code Block
    languagebash
    $ git add hello_world.krl
    $ git commit -a -m "initial commit"
    All Flushing com.windley.hello_worldrulessets parse
    [master (root-commit) 4a2f95c] initial commit
     1 file changed, 34 insertions(+)
     create mode 100644 hello_world.krl

    With the pre-commit hook in place, you're assured that there are no parse errors in your ruleset if it commits.

Register

Registering a ruleset associates its ruleset ID (RID) with a URL where it is located.

Because rulesets in KRL are hosted internet objects, the engine loads, parses, compiles, and caches them for efficiency. Each ruleset only needs to be registered once on a given pico engine. Registering the ruleset associates its RID with the URL where it's found. The RID is taken from the ruleset source. It's the identifier that directly follows the ruleset keyword. Best practice is to use a reversed domain name that you control in the RID to ensure uniqueness since two developers could choose the same name otherwise. 

Register the ruleset with the pico engine. There are automated ways to do this, but for initial development, you can do in manually. Navigate to the rulesets.html resource on your engine (i.e. if you engine is running at localhost:8080, then go to http://localhost:8080/rulesets.html. You can enter the URL of the ruleset in the box marked in red in the screen shot below. You can use the file: URL scheme to load the ruleset from the filesystem directly into the engine rather than relying on an external server. The file URL is the schema file:// prepended to the full pathname of the file (yes, there are three slashes): 

Deploy

Deploying consists of installing the ruleset in any picos it needs to run in. If the ruleset has already been installed, then it will just need to be flushed. 

Installing

Install the ruleset in your pico by navigating to the Rulesets tab in the developer interface. 
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To install the ruleset, you need its URL. If you are committing to Github, then you can use the raw URL from Github.

If you are running locally for testing, then you can install from the file using file:// followed by the full path to the KRL file. Note that you'll end up with something like file:///Users/pjw

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File-based URLs work great for development where quick turnaround is needed. If you want to host rulesets somewhere else, please be sure to read the tips for hosting rulesets

Again, you only need a register a ruleset once on any engine, even if the source code changes. The only reason to re-register a ruleset is if it's RID or URL change.  

Deploy

Deploying includes two different tasks: flushing cached artifacts from the ruleset in the engine and installing the ruleset in any picos it needs to run in. with three slashes after file:

Once the ruleset is installed, it will show up in the Installed Rulesets section of this page

Flushing

Because the engine compiles and caches the ruleset, whenever you make changes to the source, you need to flush the ruleset.

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Installing

Install the ruleset in your pico by navigating to the Rulesets tab in the pico interface. For rulesets that you've already registered, you can simply select their name from the pulldown menu and click "install ruleset". 
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Note that you can register and install the ruleset in one step from this page for convenience by installing from a URL. 

Test 

The pico engine UI For development and testing, you can do that manually from the Installed Rulesets section of the develop interface. 

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This will flush the ruleset for all picos on this instance of the pico-engine. The hash will change with each new version of the file and is unique for every version of the file. 

If you have not parsed your rulesets when you commit them (as described above) then the developer interface will show you any errors when you install or flush the ruleset. 

Test 

The developer interface includes support for testing your rulesets. See the detailed instructions for more information on how to configure and use that feature. 

The Logging tab in the pico engine UI developer interface is also helpful in debugging and testing rules. 

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If you're releasing a ruleset for broader use beyond your own needs, you'll want to take steps to ensure others see a stable ruleset even though you may continue to work on it. Putting your ruleset on an HTTP server allows it to be registered with multiple engines

The use of versions in your ruleset can ensure that picos see the version they need to operate correctly

The first step is to decide where you want to host your rulesets. Any HTTP server will do. Here are some tips for hosting code on GitHub and AWS

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