Julia Modules for Data Science

Step 1: Create the Solver.jl Module

Create a new file named Solver.jl with the following content:

Solver.jl:

module Solver  
  
using JSON3  
using DataFrames  
using Dates  
  
export Solver  
  
function Solver(json_string::String)::String  
    json_start_timestamp = now()  
    json_data = JSON3.read(json_string)  
  
    optimization_id = get(json_data, "OptimizationId", nothing)  
    has_vol_nut = 0  
    vol_nut = nothing  
    details = get(json_data, "Details", nothing)  
  
    if details !== nothing  
        if haskey(details, "VolumeNutrientId") && details["VolumeNutrientId"] !== nothing  
            has_vol_nut = 1  
            vol_nut = details["VolumeNutrientId"]  
        end  
    end  
  
    if has_vol_nut == 1  
        df_deetz = DataFrame(details)  
    else  
        df_deetz = DataFrame(Dict("VolNut" => "Nope"))  
    end  
  
    # Simulate data processing (In reality, you might want to do more complex operations)  
    processed_data = Dict(  
        "OptimizationId" => optimization_id,  
        "HasVolumeNutrient" => has_vol_nut,  
        "VolumeNutrientId" => vol_nut,  
        "Details" => JSON3.write(df_deetz)  
    )  
  
    return JSON3.write(processed_data)  
end  
  
end  

Step 2: Modify the HTTP Service to Use the Solver Module

Next, modify your main file to use the Solver module. Let's assume your main file is named server.jl.

server.jl:

using HTTP  
using JSON3  
include("Solver.jl")  
using .Solver  
  
function handle_request(req::HTTP.Request)  
    try  
        # Read and parse the JSON body  
        body = String(req.body)  
          
        # Process the data using the Solver function  
        response_json = Solver(body)  
          
        return HTTP.Response(200, response_json; headers = ["Content-Type" => "application/json"])  
    catch e  
        return HTTP.Response(400, "Bad Request: $(e)")  
    end  
end  
  
function start_server()  
    HTTP.serve(handle_request, "0.0.0.0", 8080)  
end  
  
start_server()  

Step 3: Create a Dockerfile

Create a Dockerfile to build and run your Julia HTTP service.

Dockerfile:

# Use the official Julia image as a parent image  
FROM julia:1.11.1  
  
# Set the working directory in the container  
WORKDIR /usr/src/app  
  
# Copy the current directory contents into the container at /usr/src/app  
COPY . .  
  
# Install dependencies  
RUN julia -e 'using Pkg; Pkg.add(["HTTP", "JSON3", "DataFrames"])'  
  
# Run server.jl when the container launches  
CMD ["julia", "server.jl"]  

Step 4: Build and Run the Docker Container

Build the Docker image:

docker build -t julia-http-service .

1. Run the Docker container:

docker run -p 8080:8080 julia-http-service

Summary

Created an external module Solver that processes the JSON data from the HTTP request. Modified your HTTP service to use this external module. Created a Dockerfile to containerize your service.