Jolie Slicer

Jolie Slicer is a command line tool to support the development of Jolie applications following the the Sliceable Monolith development methodology. This tool allows to run a sliceable monolith application locally in a single process (via the --run option) or to slice it into a set of services (with --slice) that can be deployed and run in a containerized environment, such as Docker.

Installing

The tool is available as a Docker image on github:

docker pull ghcr.io/jolie/slicer:latest

and as a package on npm:

npm install -g @jolie/slicer

Usage:

jolieslicer application.ol configuration.json [options]

Sliceable Monolith

1. The entire microservices architecture is coded in a single Jolie file (application.ol):

   1. Services are parameterised by their deployment configuration (configuration)
   2. Input and Output ports are parameterized by their deployment location available under the path configuration.ServiceName.locations

   As an example:

   service Gateway( configuration ) {
     inputPort ip {
       location: configuration.Gateway.locations[0]
       ...
     }
     outputPort CommandSide {
       location: configuration.CommandSide.locations[0]
       ...
     }
     main { ... }
   }

2. A configuration file (configuration.json) describes the services in the architecture, their ports, and initialisation parameters:

   {
     "Gateway": {
       "ports": [
         8080
       ],
       "params": { ... }
     },
     "CommandSide": {
       "ports": [
         "internal"
       ],
       "params": { ... }
     },
     ...
   }

   Services provide their functionality through one or more ports, each declared as either:

   • Internal ("internal") and accessible only by services in the same deployment;
   • External (e.g., 8080) and accessible by external clients through a TCP socket.

   Initialisation parameters for each service can be provided under "params".

3. The Jolie Slicer can now be used to either:

   1. Run the microservices architecture as a single executable:

      jolieslicer application.ol configuration.json --run

   2. Slice the monolith into separate codebases and

      jolieslicer application.ol configuration.json--slice output_directory

See example/ for an example application and "Sliceable Monolith: Monolith First, Microservices Later" (Picotti et al. 2021) for details on the Sliceable Monolith methodology see .