Deploy Flow Library

Now that FlowLibrary is created and Didact's applications are installed on your machine, it's time to generate a new deployment for FlowLibrary so that it can be consumed by Didact Engine.

What is a deployment?

In short, think of a deployment as a runtime-plugin equivalent of a NuGet package. It's a packaged-up class library that is loaded in dynamically to Didact Engine.

Normally, when you need to add a class library dependency to a host app, you publish the class library as a NuGet package and add the NuGet package to the host app before compile time. However, taking this approach for background jobs has a swath of disadvantages, so instead Didact loads class libraries as runtime plugins.

KISS

See Flow Library and Didact Engine to learn more about the architecture and justification.

Deploy to filesystem

Since, for the Quickstart, you'll be running Didact's apps on your local dev machine, let's use the simple filesystem deployment source for FlowLibrary.

In your terminal, run the following deploy filesystem command:

didact deploy filesystem --project FlowLibrary.csproj

where --project is the path to FlowLibrary's .csproj.

No --path param?

One nice optimization of the deploy filesystem command is that Didact automatically uses a default deployments filepath if the --path option is omitted.

Deployment workflow

So wait, why do we even need a deployment command in the first place? In short, because deployment commands like the one above drastically simplify what would otherwise be an unpleasant workflow for you.

Class library vs. host app

Remember, FlowLibrary is a class library, not a host app. This means that the class library needs to be nicely packaged up, placed somewhere discoverable, and consumed by Didact Engine in order for the flows inside to execute. This should look familiar because several ideas overlap with publishing NuGet packages, except in Didact we use runtime plugins instead.

Deployment commands typically do the following:

1. Runs dotnet publish against your flow library to produce publish artifacts which primarily consist of the project's main .dll file.
2. Packages the publish artifacts into a zip folder.
3. Infers or resolves a deployment name for your published flow library.
4. Moves the zip folder to the designated deployment source, wherever that may be.
5. Creates new deployment metadata in the Didact database.

As you can see, that's an ugly workflow, so I'd rather have Didact take care of that for you! Once a deployment command runs successfully, a flow library is discoverable and consumable by Didact Engine.