Code Execution Configuration Guide

The Code Execution Service runs learner code in a sandboxed environment. There are three interaction types, served by two distinct configuration formats:

Type	Purpose	Config Format
Post	Learner posts code to an activity (scored).	Post & Submission Config
Submission	Learner submits an exam response (scored).	Post & Submission Config
Run	Learner clicks "Run" in an interactive IDE widget (not scored).	IDE Runtime Config

Posts and Submissions share the same configuration format. Both result in a score, status, and feedback panels rendered back to the learner. Posts can also include a thumbnail.
IDE Runtime configs are completely separate. They define how to compile/run code interactively and stream stdout/stderr back — no scoring, no feedback panels.

Package Structure (ZIP vs JSON)
Post & Submission Config
- Lifecycle
- Full Example
- Fields
- setup
- compile and run
- status
- score
- thumbnail
- feedback
- show_files
IDE Runtime Config
Data Dictionary
Example Configurations
- Python
- C
- Java

Package Structure (ZIP vs JSON)

Both config formats can be uploaded as either a ZIP package or a single JSON file.

ZIP package

Use a ZIP when you need supporting files alongside config.json (test files, helper libraries, fixtures, multi-line shell scripts).

my_activity.zip
├── config.json            <-- REQUIRED  (the configuration)
├── run                    <-- REQUIRED  (Bash entry point, no extension)
├── compile                <-- OPTIONAL  (Bash build script, no extension)
├── tests/                 <-- your test files / fixtures
│   ├── test_main.py
│   └── data.csv
├── src/                   <-- (Post/Submission only) cleared and replaced with the
│                              learner's submission, see `setup.submission_dir`
└── solution_template.py   <-- can be deleted via `setup.remove_paths`

run and compile must be Bash scripts with no file extension.
compile is only needed for compiled languages (C, C++, Java, ...).
For Post/Submission configs, the directory named by setup.submission_dir (default submission) is automatically cleared and replaced with the learner's files — you do not need to list it in remove_paths.

JSON file

Use a single JSON file when the configuration is self-contained — no extra files, and compile/run are short enough to inline as strings.

When a JSON file is uploaded the system synthesises an equivalent ZIP:

my_config.json  =>  my_config.zip
                    ├── config.json   <-- copy of my_config.json
                    ├── run           <-- contents of the "run" property
                    └── compile       <-- contents of the "compile" property (if present)

If a ZIP also defines compile / run properties inside its config.json, those property values overwrite any compile / run script files present in the ZIP.

Note (IDE Runtime): in the IDE Runtime config, compile and run are objects, not strings, so the auto-conversion above only applies when those objects resolve to a single command. See IDE Runtime Config.

Post & Submission Config

Used for both Post and Submission interactions. After the learner's code runs, the service extracts a status, score, and any feedback panels, and reports them back to OpenLearning. For posts, an optional thumbnail can also be generated.

Lifecycle

Setup. Extract the ZIP, delete files listed in setup.remove_paths, then clear setup.submission_dir and inject the learner's submitted files there.
Execution. Run compile (if present), then run, under the resource limits in execution.
Reporting. Read status, score, and each feedback item from the configured sources (files or stdout/stderr) and return them. For posts, a thumbnail is also extracted if configured.

Post Full Example

{
  "version": "1.0",
  "setup": {
    "submission_dir": "src",
    "remove_paths": ["solution_template.py", "tests/__pycache__"]
  },
  "compile": "g++ -O3 -o autograder main.cpp tests.cpp",
  "run": "./autograder",
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20,
    "memory_limit": 256000,
    "enable_network": false
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error",
    "success_matcher": "^Passed"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "thumbnail": {
    "source": "file",
    "path": "output/plot.png",
    "format": "image"
  },
  "feedback": [
    {
      "label": "Test Report",
      "source": "file",
      "path": "output/report.txt",
      "format": "text",
      "on_missing": {
        "source": "stderr",
        "format": "text"
      }
    },
    {
      "label": "Compiler Output",
      "source": "stderr",
      "format": "terminal",
      "visible_if_empty": false
    }
  ],
  "show_files": true
}

Minimal Example (JSON-only)

{
  "version": "1.0",
  "run": "python3 -m pytest submission/ -v --tb=short && echo 100 || echo 0",
  "score": {
    "source": "stdout",
    "default": 0,
    "max_points": 100
  }
}

Post & Submission Fields

Field	Type	Required	Default	Description
`version`	`string`	Yes	—	Configuration format version. Must be `"1.0"`.
`setup`	object	No	—	File system preparation. See `setup`.
`compile`	`string`	No	—	Shell command for compilation. If omitted from the JSON, a `compile` script in the ZIP is used (if present).
`run`	`string`	No	—	Shell command to execute. If omitted from the JSON, a `run` script must exist in the ZIP.
`execution`	object	No	(defaults)	Resource limits. See `execution`.
`status`	object	No	`"Completed"`	How to derive the submission status text. See `status`.
`score`	object	No	—	How to derive the numerical score. See `score`.
`thumbnail`	object	No	—	Image to represent the post (posts only, ignored for submissions). See `thumbnail`.
`feedback`	array	No	—	Feedback panels shown to the learner. See `feedback`.
`show_files`	`boolean`	No	`true`	Show a file viewer for browsing post-execution files.

`setup`

Controls how the file system is prepared before scripts run.

Field	Type	Required	Default	Description
`submission_dir`	`string`	No	`"submission"`	Folder where the learner's submitted files are placed.
`remove_paths`	`string[]`	No	—	Files/folders in the ZIP to delete before injecting the learner's code. Supports `.gitignore` syntax.

You don't need to list files inside submission_dir in remove_paths — that directory is cleared automatically.

`compile` and `run` scripts

These are Bash scripts (or one-liner strings) that act as the bridge between the runner and your toolchain.

Example run (Python):

#!/bin/bash
python3 -m pytest tests/ --color=yes -v --tb=short --no-header > output/report.txt 2>&1
if [ $? -eq 0 ]; then
    echo "Passed" > output/status.txt
    echo "100"    > output/score.txt
else
    echo "Failed" > output/status.txt
    echo "0"      > output/score.txt
fi

`status`

A short text label representing the result. If the entire status block is omitted, it defaults to "Completed".

Field	Type	Required	Default	Description
`source`	`string`	Yes	—	Where to read status from. See source values.
`path`	`string`	No	—	File path (required if `source` is `"file"`).
`content`	`string`	No	—	Static text (required if `source` is `"static"`).
`default`	`string`	No	—	Fallback text if the source returns nothing.
`max_length`	`integer`	No	—	Maximum character length for the status string.
`success_matcher`	`string`	No	—	Regex pattern. If status matches, the submission is marked Successful. If omitted, any non-empty status counts as success.
`on_missing`	object	No	—	Fallback when the source is missing. See `on_missing`.

`score`

The numerical grade for the submission. Distinct from status — status is a label, score is the number.

Field	Type	Required	Default	Description
`source`	`string`	Yes	—	Where to read the score from. See source values.
`path`	`string`	No	—	File path (required if `source` is `"file"`).
`content`	`string`	No	—	Static value (required if `source` is `"static"`).
`default`	`float`	No	—	Fallback score if the source returns nothing.
`max_points`	`float`	No	—	Maximum possible score (used for display/scaling).
`on_missing`	object	No	—	Fallback when the source is missing. See `on_missing`.

`thumbnail`

Optional image to represent the post in the activity feed. Only used for Post interactions — ignored for submissions.

Field	Type	Required	Default	Description
`source`	`string`	Yes	—	Where to read the image from. See source values.
`path`	`string`	No	—	File path (required if `source` is `"file"`).
`content`	`string`	No	—	Static content (required if `source` is `"static"`).
`format`	`string`	No	`"image"`	Must be `"image"` or `"text"`. If `"text"`, the text is rendered into an SVG thumbnail.
`on_missing`	object	No	—	Fallback when the source is missing. See `on_missing`.

Constraint: the final result (including any on_missing fallback) must resolve to an image.

`feedback`

A list of panels displayed to the learner after execution.

Field	Type	Required	Default	Description
`label`	`string`	Yes	—	Title/heading for this panel.
`source`	`string`	Yes	—	Where to read the content from. See source values.
`path`	`string`	No	—	File path (required if `source` is `"file"`).
`content`	`string`	No	—	Static text (required if `source` is `"static"`).
`format`	`string`	No	—	How to render the content. See format values. If omitted, this item is skipped.
`visible_if_empty`	`boolean`	No	`true`	If `false`, hide this panel when content is empty.
`on_missing`	object	No	—	Fallback when the source is missing. See `on_missing`.

`show_files`

Defaults to true. Set to false to hide the post-execution file viewer in the learner's results UI.

IDE Runtime Config

Used for the Run interaction — the interactive "Run" button in an IDE widget. There is no scoring, status, thumbnail, or feedback here; the service simply compiles and/or runs the learner's code and streams back stdout, stderr, and the compile output.

The same ZIP / JSON packaging rules apply (see Package Structure). Note however that setup is not part of this config — the learner's code files are written directly into the working directory.

IDE Runtime Full Example

{
  "version": "1.0",
  "compile": {
    "command_prefix": "gcc",
    "args": "-Wall -Werror -o program program.c",
    "args_placeholder": "Compiler flags",
    "allow_custom_args": true
  },
  "run": {
    "command_prefix": "./program",
    "args_placeholder": "Command-line arguments (optional)",
    "allow_custom_args": true
  },
  "execution": {
    "cpu_time_limit": 10,
    "memory_limit": 256000
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Input data (stdin)",
    "text": "hello world"
  }
}

Minimal Example

{
  "version": "1.0",
  "run": {
    "command_prefix": "python3 main.py"
  }
}

IDE Runtime Fields

Field	Type	Required	Default	Description
`version`	`string`	Yes	—	Configuration format version. Must be `"1.0"`.
`compile`	object	No	—	Compilation command configuration. See compile/run options.
`run`	object	No	—	Run command configuration. If omitted from the JSON, a `run` script file must exist in the config ZIP. See compile/run options.
`input`	object	No	—	Standard input (stdin) configuration. See `input`.
`execution`	object	No	(defaults)	Resource limits. See `execution`.

IDE Runtime `compile` and `run` Options

The final command run is command_prefix + " " + args (whichever sides are present). Either one may be omitted, but at least one must be present (or a run script file must exist in the ZIP for run).

Field	Type	Required	Default	Description
`command_prefix`	`string`	No	—	Fixed prefix of the command. Never editable by the learner.
`args`	`string`	No	—	Default arguments. Editable by the learner only if `allow_custom_args` is `true`.
`args_placeholder`	`string`	No	`"Compiler flags"` for `compile`, `"Command-line arguments"` for `run`	Placeholder text shown in the arguments input field.
`allow_custom_args`	`boolean`	No	`false`	If `true`, the learner can edit `args`.

Patterns:

Lock everything: put the entire command in command_prefix, set allow_custom_args to false (or omit it).

Lock the binary, free the args: command_prefix: "gcc", args: "-Wall -o program program.c", allow_custom_args: true.

Free the entire command: omit command_prefix, put the default in args, set allow_custom_args: true.

`input`

Standard input (stdin) for the learner's program.

Field	Type	Required	Default	Description
`allow_editing`	`boolean`	No	`false`	If `true`, the learner can edit the stdin input.
`placeholder`	`string`	No	`"Input data (stdin)"`	Placeholder text shown in the stdin input field.
`text`	`string`	No	—	Default stdin text to pre-fill.

Data Dictionary

`execution` (shared)

Both Post/Submission and IDE Runtime configs accept the same execution block. All fields are optional — system defaults apply when omitted.

"execution": {
  "cpu_time_limit": 5.0,
  "wall_time_limit": 10.0,
  "memory_limit": 128000,
  "enable_network": false
}

Field	Type	Default	Description
`cpu_time_limit`	`float`	`5.0`	Max CPU time allowed (seconds).
`cpu_extra_time`	`float`	`1.0`	Grace period (seconds) before killing the program after the limit.
`wall_time_limit`	`float`	`10.0`	Max wall-clock time allowed (seconds).
`memory_limit`	`integer`	`128000`	Max RAM usage in kilobytes (128 MB).
`stack_limit`	`integer`	`64000`	Max stack size in kilobytes (64 MB).
`max_processes_and_or_threads`	`integer`	`60`	Max number of threads/processes allowed.
`enable_per_process_and_thread_time_limit`	`boolean`	`false`	If `true`, applies `cpu_time_limit` to each process/thread.
`enable_per_process_and_thread_memory_limit`	`boolean`	`false`	If `true`, applies `memory_limit` to each process/thread.
`max_file_size`	`integer`	`1024`	Max size of any file the program can create, in kilobytes (1 MB).
`redirect_stderr_to_stdout`	`boolean`	`false`	If `true`, merges stderr into stdout.
`enable_network`	`boolean`	`false`	If `true`, allows the program to access the internet.

The execution environment is the "Judge0 Extra CE" runtime. Only packages/tools installed in this environment are available for use.

`source` values

Used by status, score, thumbnail, feedback, and on_missing.

Value	Description	Required additional fields
`"file"`	Read content from a file produced during execution.	`path` — relative path to the file.
`"stdout"`	Capture the program's standard output stream.	(none)
`"stderr"`	Capture the program's standard error stream.	(none)
`"static"`	Use a hardcoded string value.	`content` — the static string to use.

`format` values

Used by feedback, thumbnail, and on_missing.

Value	Description
`"text"`	Displayed as a raw text code block. ANSI-colored text is auto-detected and rendered in a styled terminal.
`"terminal"`	Displayed as ANSI-colored text in a styled terminal emulator.
`"markdown"`	Rendered as Markdown (converted to HTML).
`"html"`	Rendered in a sandboxed iframe. JavaScript is allowed but restricted.
`"image"`	Displayed as an image. Content can be a URL, base64-encoded data URI, or a binary image file.
`"ppm"`	Displayed using a PPM image viewer. Accepts `.ppm`, `.pgm`, or `.pbm` files.

Constraints:

status and score are always treated as text — format cannot be set on them.
thumbnail defaults to "image". Also accepts "text", which renders the text as an SVG thumbnail.
If format is omitted on a feedback item, that item is skipped entirely.

`on_missing` fallback

If your script crashes or an output file is never produced, you can define a fallback using on_missing. It accepts the same source, path / content, and format fields as the parent block and may itself be nested.

{
  "label": "Test Report",
  "source": "file",
  "path": "output/report.txt",
  "format": "text",
  "on_missing": {
    "source": "stderr",
    "format": "text"
  }
}

on_missing is evaluated when:

source is "file" and the file does not exist.
source is "stdout" or "stderr" and the stream is empty/missing.

Example Configurations

All examples use a FizzBuzz problem: given a number N from stdin, print each number from 1 to N, replacing multiples of 3 with "Fizz", multiples of 5 with "Buzz", and multiples of both with "FizzBuzz".

Each language has three complexity levels:

Level	Testing Approach	Scoring
Simple	Bash runs the program against `.in`/`.out` files, uses `diff`	Binary: 100 or 0
Normal	Python subprocess script (or compiled test harness for C/Java) checks each case	Proportional: (passed/total) × 100
Full	Unit tests (Python `unittest`) or weighted test harness (C/Java)	Weighted: each test has assigned points

Python

IDE Runtime

Simple

The minimal config — just runs the student's file:

{
  "version": "1.0",
  "run": {
    "command_prefix": "python3 main.py"
  }
}

Download ZIP

Normal

Adds editable arguments and stdin input:

{
  "version": "1.0",
  "run": {
    "command_prefix": "python3",
    "args": "main.py",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number",
    "text": "15"
  }
}

Download ZIP — contains config.json + run script

Full

Adds a syntax-check compile step and execution limits:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "python3 -m py_compile main.py"
  },
  "run": {
    "command_prefix": "python3",
    "args": "main.py",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number (e.g. 20)",
    "text": "20"
  },
  "execution": {
    "cpu_time_limit": 5,
    "wall_time_limit": 10,
    "memory_limit": 128000,
    "enable_network": false
  }
}

Download ZIP — contains config.json + run script

Post/Submission

Simple

Runs the program against three input files and diffs against expected output. All-or-nothing scoring:

{
  "version": "1.0",
  "run": "python3 submission/main.py < 1.in > all_outputs.txt && python3 submission/main.py < 2.in >> all_outputs.txt && python3 submission/main.py < 3.in >> all_outputs.txt && cat 1.out 2.out 3.out > all_expected.txt && diff all_outputs.txt all_expected.txt > /dev/null && echo 100 || echo 0",
  "score": {
    "source": "stdout",
    "default": 0,
    "max_points": 100
  }
}

Download ZIP — contains config.json + .in/.out test data files

Normal

A Python test script runs the program per test case via subprocess. Proportional scoring:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission"
  },
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "feedback": [
    {
      "label": "Test Results",
      "source": "file",
      "path": "output/results.txt",
      "format": "text"
    }
  ]
}

Download ZIP — contains config.json + run script + test_fizzbuzz.py (subprocess-based test runner that writes score/status/results to output/)

Full

Uses unittest to import and test the student's function directly. Weighted scoring, thumbnail, multiple feedback panels with fallbacks:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission",
    "remove_paths": ["solution_template.py"]
  },
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20,
    "memory_limit": 256000,
    "enable_network": false
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error",
    "success_matcher": "^All Tests Passed"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "thumbnail": {
    "source": "file",
    "path": "output/thumbnail.txt",
    "format": "text"
  },
  "feedback": [
    {
      "label": "Test Report",
      "source": "file",
      "path": "output/report.md",
      "format": "markdown",
      "on_missing": {
        "source": "stderr",
        "format": "terminal"
      }
    },
    {
      "label": "Program Output",
      "source": "stdout",
      "format": "terminal",
      "visible_if_empty": false
    }
  ],
  "show_files": true
}

Download ZIP — contains config.json + run script + run_tests.py (weighted unittest runner) + solution_template.py (starter code deleted via remove_paths)

C

IDE Runtime

Simple

Compile and run with no options:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "gcc -o fizzbuzz main.c"
  },
  "run": {
    "command_prefix": "./fizzbuzz"
  }
}

Download ZIP

Normal

Editable compiler flags, editable run arguments, and stdin input:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "gcc",
    "args": "-o fizzbuzz main.c",
    "args_placeholder": "Compiler flags",
    "allow_custom_args": true
  },
  "run": {
    "command_prefix": "./fizzbuzz",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number",
    "text": "15"
  }
}

Download ZIP — contains config.json + compile script + run script

Full

Strict compiler flags and execution limits:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "gcc",
    "args": "-Wall -Werror -O2 -o fizzbuzz main.c",
    "args_placeholder": "Compiler flags",
    "allow_custom_args": true
  },
  "run": {
    "command_prefix": "./fizzbuzz",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number (e.g. 20)",
    "text": "20"
  },
  "execution": {
    "cpu_time_limit": 5,
    "wall_time_limit": 10,
    "memory_limit": 128000,
    "max_processes_and_or_threads": 1,
    "enable_network": false
  }
}

Download ZIP — contains config.json + compile script + run script

Post/Submission

Simple

Compiles and runs against .in/.out files. All-or-nothing:

{
  "version": "1.0",
  "compile": "gcc -o fizzbuzz submission/main.c",
  "run": "./fizzbuzz < 1.in > all_outputs.txt && ./fizzbuzz < 2.in >> all_outputs.txt && ./fizzbuzz < 3.in >> all_outputs.txt && cat 1.out 2.out 3.out > all_expected.txt && diff all_outputs.txt all_expected.txt > /dev/null && echo 100 || echo 0",
  "score": {
    "source": "stdout",
    "default": 0,
    "max_points": 100
  }
}

Download ZIP — contains config.json + .in/.out test data files

Normal

A C test harness compiled together with the student's code. Tests the fizzbuzz() function directly:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission"
  },
  "compile": "gcc -O2 -o test_runner test_fizzbuzz.c submission/fizzbuzz.c -lm",
  "execution": {
    "cpu_time_limit": 5,
    "wall_time_limit": 10
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "feedback": [
    {
      "label": "Test Results",
      "source": "file",
      "path": "output/results.txt",
      "format": "text",
      "on_missing": {
        "source": "stderr",
        "format": "terminal"
      }
    }
  ]
}

Download ZIP — contains config.json + compile script + run script + test_fizzbuzz.c (test harness that calls extern const char* fizzbuzz(int n) and writes results to output/)

Full

Weighted scoring, strict compilation, thumbnail, multiple feedback panels:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission",
    "remove_paths": ["fizzbuzz_template.c"]
  },
  "compile": "gcc -Wall -Werror -O2 -o test_runner test_fizzbuzz.c submission/fizzbuzz.c -lm",
  "execution": {
    "cpu_time_limit": 5,
    "wall_time_limit": 10,
    "memory_limit": 128000,
    "max_processes_and_or_threads": 1,
    "enable_network": false
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error",
    "success_matcher": "^All Tests Passed"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "thumbnail": {
    "source": "file",
    "path": "output/thumbnail.txt",
    "format": "text"
  },
  "feedback": [
    {
      "label": "Test Report",
      "source": "file",
      "path": "output/report.md",
      "format": "markdown",
      "on_missing": {
        "source": "stderr",
        "format": "terminal"
      }
    },
    {
      "label": "Compiler Output",
      "source": "stderr",
      "format": "terminal",
      "visible_if_empty": false
    }
  ],
  "show_files": true
}

Download ZIP — contains config.json + compile script + run script + test_fizzbuzz.c (weighted test harness writing markdown report) + fizzbuzz_template.c (starter code deleted via remove_paths)

Java

IDE Runtime

Simple

Compile and run:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "javac Main.java"
  },
  "run": {
    "command_prefix": "java Main"
  }
}

Download ZIP

Normal

Editable compiler flags and stdin input:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "javac",
    "args": "Main.java",
    "args_placeholder": "Compiler flags",
    "allow_custom_args": true
  },
  "run": {
    "command_prefix": "java Main",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number",
    "text": "15"
  }
}

Download ZIP — contains config.json + compile script + run script

Full

Full options with execution limits:

{
  "version": "1.0",
  "compile": {
    "command_prefix": "javac",
    "args": "Main.java",
    "args_placeholder": "Compiler flags",
    "allow_custom_args": true
  },
  "run": {
    "command_prefix": "java",
    "args": "Main",
    "args_placeholder": "Command-line arguments",
    "allow_custom_args": true
  },
  "input": {
    "allow_editing": true,
    "placeholder": "Enter a number (e.g. 20)",
    "text": "20"
  },
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20,
    "memory_limit": 256000,
    "enable_network": false
  }
}

Download ZIP — contains config.json + compile script + run script

Post/Submission

Simple

Compiles and runs against .in/.out files. All-or-nothing:

{
  "version": "1.0",
  "compile": "javac submission/Main.java",
  "run": "java -cp submission Main < 1.in > all_outputs.txt && java -cp submission Main < 2.in >> all_outputs.txt && java -cp submission Main < 3.in >> all_outputs.txt && cat 1.out 2.out 3.out > all_expected.txt && diff all_outputs.txt all_expected.txt > /dev/null && echo 100 || echo 0",
  "score": {
    "source": "stdout",
    "default": 0,
    "max_points": 100
  }
}

Download ZIP — contains config.json + .in/.out test data files

Normal

A Java test harness compiled with the student's code. Tests the FizzBuzz.fizzbuzz() method directly:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission"
  },
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20,
    "memory_limit": 256000
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "feedback": [
    {
      "label": "Test Results",
      "source": "file",
      "path": "output/results.txt",
      "format": "text",
      "on_missing": {
        "source": "stderr",
        "format": "terminal"
      }
    }
  ]
}

Download ZIP — contains config.json + compile script + run script + TestFizzBuzz.java (test harness that calls FizzBuzz.fizzbuzz() and writes results to output/)

Full

Weighted scoring, thumbnail, multiple feedback panels:

{
  "version": "1.0",
  "setup": {
    "submission_dir": "submission",
    "remove_paths": ["FizzBuzzTemplate.java"]
  },
  "execution": {
    "cpu_time_limit": 10,
    "wall_time_limit": 20,
    "memory_limit": 256000,
    "enable_network": false
  },
  "status": {
    "source": "file",
    "path": "output/status.txt",
    "default": "Error",
    "success_matcher": "^All Tests Passed"
  },
  "score": {
    "source": "file",
    "path": "output/score.txt",
    "default": 0,
    "max_points": 100
  },
  "thumbnail": {
    "source": "file",
    "path": "output/thumbnail.txt",
    "format": "text"
  },
  "feedback": [
    {
      "label": "Test Report",
      "source": "file",
      "path": "output/report.md",
      "format": "markdown",
      "on_missing": {
        "source": "stderr",
        "format": "terminal"
      }
    },
    {
      "label": "Compiler Output",
      "source": "stderr",
      "format": "terminal",
      "visible_if_empty": false
    }
  ],
  "show_files": true
}

Download ZIP — contains config.json + compile script + run script + TestFizzBuzz.java (weighted test harness writing markdown report) + FizzBuzzTemplate.java (starter code deleted via remove_paths)

Code Execution Configuration Guide

Table of Contents

Package Structure (ZIP vs JSON)

ZIP package

JSON file

Post & Submission Config

Lifecycle

Post Full Example

Minimal Example (JSON-only)

Post & Submission Fields

setup

compile and run scripts

status

score

thumbnail

feedback

show_files

IDE Runtime Config

IDE Runtime Full Example

Minimal Example

IDE Runtime Fields

IDE Runtime compile and run Options

input

Data Dictionary

execution (shared)

source values

format values

on_missing fallback

Example Configurations

Python

IDE Runtime

Simple

Normal

Full

Post/Submission

Simple

Normal

Full

C

IDE Runtime

Simple

Normal

Full

Post/Submission

Simple

Normal

Full

Java

IDE Runtime

Simple

Normal

Full

Post/Submission

Simple

Normal

Full

`setup`

`compile` and `run` scripts

`status`

`score`

`thumbnail`

`feedback`

`show_files`

IDE Runtime `compile` and `run` Options

`input`

`execution` (shared)

`source` values

`format` values

`on_missing` fallback