CustomChecker.rb

# Start of HEAD
require 'json'

TestStruct = Struct.new(
    :testcase_id,
    :testcase_input_path,
    :testcase_output_path,
    :testcase_expected_output_path,
    :metadata_file_paths,
    :submission_code_path,
    :testcase_result,
    :testcase_signal,
    :testcase_time,
    :testcase_memory,
    :data
)

ResultStruct = Struct.new(
    :result,
    :score,
    :message
)
# End of HEAD

# Start of BODY
=begin
 TestStruct::
  testcase_id                   [long] ID of the test-case
  testcase_input_path           [String] File path to test-case input
  testcase_output_path          [String] File path to test-case output generated by the problem solver
  testcase_expected_output_path [String] File path to test-case expected output to be matched with
  metadata_file_paths           [ArrayList<String>] File paths to Question metadata (Extra files usually used for defining traning sets)
  submission_code_path          [String] File path to submission source code
  testcase_result               [boolean] Set to true if test-case output matches test-case expected output. Matching is done line by line
  testcase_signal               [long] Exit code of the test-case process
  testcase_time                 [double] Time taken by the test-case process in seconds
  testcase_memory               [long] Peak memory of the test-case process determined in bytes
  data                          [String] <Future use>

  ResultStruct::
    result      [boolean]  Assign test-case result. true determines success. false determines failure
    score       [double] Assing test-case score. Normalized between 0 to 1
    message     [String] Assing test-case message. This message is visible to the problem solver
=end

# run_custom_checker(TestStruct, ResultStruct)
def run_custom_checker(t_obj, r_obj)
    # Don't print anything to STDOUT in this function
    # Enter your custom checker scoring logic here
    puts "testcase_id: #{t_obj.testcase_id}"
    puts "testcase_input_path: #{t_obj.testcase_input_path}"
    puts "testcase_output_path: #{t_obj.testcase_output_path}"
    puts "testcase_expected_output_path: #{t_obj.testcase_expected_output_path}"
    t_obj.metadata_file_paths.each do |it|
        puts "metadata_file_paths: #{it}"
    end
    puts "submission_code_path: #{t_obj.submission_code_path}"
    puts "testcase_result: #{t_obj.testcase_result}"
    puts "testcase_signal: #{t_obj.testcase_signal}"
    puts "testcase_time: #{t_obj.testcase_time}"
    puts "testcase_memory: #{t_obj.testcase_memory}"
    puts "data: #{t_obj.data}"

    r_obj.result = true;
    r_obj.score = 1.0;
    r_obj.message = "Success";
end
# End of BODY

# Start of TAIL
def read_input_json(json_file_path, t_obj)
    file_contents = File.read(json_file_path)
    json_obj = JSON.parse (file_contents)
    begin
        # Read values
        t_obj.testcase_id = json_obj["testcase_id"]
        t_obj.testcase_input_path = json_obj["input_file_path"]
        t_obj.testcase_output_path = json_obj["output_file_path"]
        t_obj.testcase_expected_output_path = json_obj["expected_output_file_path"]

        metadata_file_path_node = json_obj["metadata_file_paths"]
        if metadata_file_path_node
            metadata_file_path_node.each do |metadata_file_path|
                t_obj.metadata_file_paths << metadata_file_path
            end
        end

        t_obj.submission_code_path = json_obj["submission_code_path"]
        t_obj.testcase_result = json_obj["testcase_result"]
        t_obj.testcase_signal = json_obj["testcase_signal"]
        t_obj.testcase_time = json_obj["testcase_time"]
        t_obj.testcase_memory = json_obj["testcase_memory"]
        t_obj.data = json_obj["data"]
    rescue => err
        return true
    end
    
    return false
end

def write_result_json(r_obj)
    json_obj = {
        custom_result: if r_obj.result then 1 else 0 end,
        custom_score: if r_obj.score > 1 then 1 elsif r_obj.score < 0 then 0 else r_obj.score end,
        custom_message: r_obj.message[0..4095]
    }

    puts json_obj.to_json
end

# Input parameters
t_obj = TestStruct.new(
    0,
    "",
    "",
    "",
    [],
    "",
    false,
    0,
    0.0,
    0,
    ""
)

# Out parameters
r_obj = ResultStruct.new(
    false,
    0.0,
    "Uninitialized"
)

if(ARGV.length < 1)
    write_result_json(r_obj)
    abort()
end

# Decode input JSON
failure = read_input_json(ARGV[0], t_obj)
# Incase input JSON was malformed or not existent
if failure
    r_obj.message = "Unable to read input json";
    write_result_json(r_obj);
    abort()
end

# Run the custom checker evaluator
run_custom_checker(t_obj, r_obj);

# Encode result JSON
write_result_json(r_obj);

# End of TAIL

Testing:
Input file data. Path to be passed as command line argument

{"testcase_id":0,"input_file_path":"/run-XX/input00.txt","output_file_path":"/run-XX/output00.out","expected_output_file_path":"/run-XX/output_expected00.out","metadata_file_paths":["/run-XX/training.txt","/run-XX/training2.txt"],"submission_code_path":"/run-XX/solution.cpp", "testcase_result":true,"testcase_signal":0,"testcase_time":1.2,"testcase_memory":312322,"data":"Data"}

Expected output:

testcase_id:  0
testcase_input_path:  /run-XX/input00.txt
testcase_output_path:  /run-XX/output00.out
testcase_expected_output_path:  /run-XX/output_expected00.out
metadata_file_paths:  /run-XX/training.txt
metadata_file_paths:  /run-XX/training2.txt
submission_code_path:  /run-XX/solution.cpp
testcase_result:  True
testcase_signal:  0
testcase_time:  1.2
testcase_memory:  312322
data:  Data
{"custom_result": 1, "custom_score": 1.0, "custom_message": "Success"}