Capsula

[!WARNING] This project is in early development. The CLI interface and configuration format may change in future releases.

A powerful CLI tool for running hooks and capturing their output before and after your command executions. Capsula automatically records the state of your project environment before and after running commands, making your workflows reproducible and auditable.

[!NOTE] The Python version of Capsula is deprecated and can be found at the python branch of this repository.

Features

📸 Context Capture: Automatically capture git state, file contents, environment variables, and more
🔄 Reproducible Runs: Complete record of execution hook for debugging and auditing
🛡️ Safety Checks: Prevent execution on dirty repositories or other unsafe conditions
📊 Structured Output: JSON-formatted capture data for easy processing
🔧 Extensible: Multiple built-in hooks with clean error handling

Installation / Update

Rust 1.90.0 or later is required.

To install Capsula CLI or update to the latest version, use one of the following methods:

Install from crates.io (recommended)

cargo install capsula-cli --locked

Install from the GitHub repository

cargo install --git https://github.com/shunichironomura/capsula --locked capsula-cli

Quick Start

Create a configuration file (capsula.toml) in your project root:

[vault]
name = "my-project"

[[pre-run.hooks]]
id = "capture-git-repo"
name = "repo-name"
path = "."

[[pre-run.hooks]]
id = "capture-cwd"

[[pre-run.hooks]]
id = "capture-file"
glob = "config.json"
mode = "copy"
hash = "sha256"

Run a command with hooks:

capsula run python train_model.py

Configuration

Basic Structure

The capsula.toml configuration file defines:

Vault: Where to store captured data
Phases: Pre-run and post-run hooks

[vault]
name = "project-name"        # Vault identifier
path = ".capsula"           # Storage path (optional, defaults to .capsula/{name})

[pre-run]                 # Pre-execution hooks
[[pre-run.hooks]]
id = "capture-git-repo"
# ... hook configuration

[post-run]                # Post-execution hooks
[[post-run.hooks]]
id = "capture-file"
# ... hook configuration

Available Hook Types

Git Hook

Captures git repository state including commit hash and cleanliness check.

[[pre-run.hooks]]
id = "capture-git-repo"
name = "repo-name"          # Hook name
path = "."                  # Repository path
allow_dirty = false         # Allow uncommitted changes (default: false)

Output Example:

{
  "__meta": {
    "config": {
      "name": "repo-name",
      "path": ".",
      "allow_dirty": false
    },
    "id": "capture-git-repo",
    "success": true
  },
  "working_dir": "/path/to/repo",
  "sha": "abc123...",
  "is_dirty": false,
  "abort_on_dirty": false
}

Current Working Directory

Captures the current working directory path.

[[pre-run.hooks]]
id = "capture-cwd"

Output Example:

{
  "__meta": {
    "config": {},
    "id": "capture-cwd",
    "success": true
  },
  "cwd": "/current/working/directory"
}

File Hook

Captures file contents and/or metadata.

[[pre-run.hooks]]
id = "capture-file"
glob = "config.json"        # File pattern to capture
mode = "copy"               # Capture mode ("copy", "move", or "none". default: "copy")
hash = "sha256"             # Calculate file hash ("sha256" or "none". default: "sha256")

Output Example:

{
  "__meta": {
    "config": {
      "glob": "config.json",
      "mode": "copy",
      "hash": "sha256"
    },
    "id": "capture-file",
    "success": true
  },
  "files": [
    {
      "path": "/path/to/config.json",
      "copied_path": "/vault/run-dir/config.json",
      "hash": "sha256:abc123..."
    }
  ]
}

Environment Variables Hook

Captures specified environment variables.

[[pre-run.hooks]]
id = "capture-env"
name = "HOME"                 # Variable name to capture

Output Example:

{
  "__meta": {
    "config": {
      "name": "HOME"
    },
    "id": "capture-env",
    "success": true
  },
  "value": "/home/user"
}

Command Hook

Captures output of shell commands.

[[pre-run.hooks]]
id = "capture-command"
command = ["uname", "-a"]
abort_on_failure  = false  # Abort if command fails (default: false)

Output Example:

{
  "__meta": {
    "config": {
      "command": ["rustc", "--version"],
      "abort_on_failure": false
    },
    "id": "capture-command",
    "success": true
  },
  "status": 0,
  "stdout": "rustc 1.91.0 (f8297e351 2025-10-28)\n",
  "stderr": "",
  "abort_requested": false
}

Machine Hook

Captures system information like CPU, memory, and OS details.

[[pre-run.hooks]]
id = "capture-machine"

Output Example:

{
  "__meta": {
    "config": {},
    "id": "capture-machine",
    "success": true
  },
  "hostname": "hostname.local",
  "os": "Darwin",
  "os_version": "26.0.1",
  "kernel_version": "25.0.0",
  "architecture": "aarch64",
  "total_memory": 137438953472,
  "cpus": [
    {
      "name": "1",
      "brand": "Apple M3 Max",
      "vender_id": "Apple",
      "frequency_mhz": 4056
    }
  ]
}

Slack Notification Hook

Sends notifications to a Slack channel when a run starts (pre-run phase) or completes (post-run phase).

# Send to a channel
[[pre-run.hooks]]
id = "notify-slack"
channel = "#general"        # Slack channel name (or channel ID like "C01234567")
token = "xoxb-..."          # Slack bot token (optional, can use SLACK_BOT_TOKEN env var)

# Send as a DM to a user
[[post-run.hooks]]
id = "notify-slack"
channel = "U01234ABCD"      # Slack user ID for DMs (not @username)
# Token will be read from SLACK_BOT_TOKEN env var

[!TIP] It's recommended to set the Slack bot token via the SLACK_BOT_TOKEN environment variable instead of storing it in the configuration file. If the token field is omitted from the configuration, Capsula will automatically read it from the environment variable.

Pre-run notification message:

Run `chubby-back` (ID: `01K8WSYC91YAE21R7CWHQ4KYN2`) is starting.

Post-run notification message:

Run `chubby-back` (ID: `01K8WSYC91YAE21R7CWHQ4KYN2`) has completed.

Output Example:

{
  "__meta": {
    "config": {
      "channel": "C01234567",
      "token": "xoxb-..."
    },
    "id": "notify-slack",
    "success": true
  },
  "message": "Slack notification sent successfully",
  "response": "{\"ok\":true,\"channel\":\"C01234567\",\"ts\":\"1234567890.123456\"}"
}

Setup Requirements:

To use the Slack notification hook, you need to:

Create a Slack app at https://api.slack.com/apps
Add the chat:write bot token scope to your app
Install the app to your workspace
Copy the bot token (starts with xoxb-)
Set the SLACK_BOT_TOKEN environment variable or add it to your config
For channel notifications: Invite the bot to the channel you want to post to
For DM notifications: Find the user ID by clicking the user's profile → "More" → "Copy member ID" (format: U01234ABCD)

CLI Usage

Commands

`capsula run <command>`

Execute a command with full hook capture.

# Run with default config
capsula run python script.py

# Run with custom config
capsula run --config my-config.toml python script.py

# Run with arguments
capsula run python train.py --epochs 100 --lr 0.01

Behavior:

Runs pre-run hooks and saves their outputs to vault
Checks for abort conditions (e.g., dirty git repo)
Executes the command if safe, aborts otherwise
Runs post-run hooks and saves their outputs to vault

Environment Variables:

When executing a command with capsula run, the following environment variables are automatically set and available to your command:

Variable	Description	Example
`CAPSULA_RUN_ID`	Unique ULID identifier for this run	`01K8WSYC91YAE21R7CWHQ4KYN2`
`CAPSULA_RUN_NAME`	Human-readable generated name	`chubby-back`
`CAPSULA_RUN_DIRECTORY`	Absolute path to the run directory in the vault	`/path/to/.capsula/vault-name/2025-10-31/093525-chubby-back`
`CAPSULA_RUN_TIMESTAMP`	ISO 8601 timestamp of when the run started	`2025-10-31T09:35:25.473+00:00`
`CAPSULA_RUN_COMMAND`	Shell-quoted string of the executed command	`python train.py --epochs 100`
`CAPSULA_PRE_RUN_OUTPUT_PATH`	Path to the pre-run output JSON file	`/path/to/.capsula/vault-name/.../pre-run.json`

[!CAUTION] While CAPSULA_RUN_DIRECTORY is available, it is not recommended to write files directly to this directory. Instead, output files to your project root and capture them using the capture-file hook in the post-run phase. This approach ensures files are properly tracked and managed by Capsula's file handling system.

These variables can be used within your scripts to access run metadata:

# Example: Embed run name in matplotlib figures for traceability
import os
import matplotlib.pyplot as plt

run_name = os.environ.get('CAPSULA_RUN_NAME')

# Create your plot
plt.plot([1, 2, 3, 4], [1, 4, 2, 3])
plt.title('Experiment Results')

# Add run name to the figure - useful when copying plots to presentations
plt.figtext(0.99, 0.01, f'Run: {run_name}',
            ha='right', va='bottom', fontsize=8, alpha=0.7)

# Save to project root, then capture with post-run hook
plt.savefig('results.png')

# Configure a post-run hook to capture the output file
[[post-run.hooks]]
id = "capture-file"
glob = "results.png"
mode = "move"  # Move the file to the vault

`capsula list`

List all captured runs in the vault.

# List runs with default config
capsula list

# List runs with custom config
capsula list --config my-config.toml

Example Output:

TIMESTAMP (UTC)      NAME                  COMMAND
---------------------------------------------------------------------------------------------
2025-10-31 09:35:29  kind-year             echo hello
2025-10-31 09:35:28  smelly-apparel        echo hello
2025-10-31 09:35:26  clear-waste           echo hello
2025-10-31 09:30:15  cheap-trip            echo this is a very long command with many argu...

The output shows:

Timestamp: UTC time when the command was executed
Name: Human-readable generated name for the run
Command: The command that was executed (truncated if too long)

Output Structure

Metadata

Every hook output includes metadata for traceability:

{
  "__meta": {
    "config": {},    // Configuration used for this hook
    "id": "capture-cwd",  // Hook ID from configuration
    "success": true  // Capture success status
  }
  // ... hook-specific data
}

Vault Structure

Captured data is organized in the vault:

.capsula/
└── vault-name/
    └── 2025-10-31/                    # Date-based directory (YYYY-MM-DD, UTC)
        └── 093525-chubby-back/        # Unique run directory (HHMMSS-run-name)
            ├── _capsula/              # Capsula metadata directory
            │   ├── metadata.json      # Run metadata (ID, name, command, timestamp)
            │   ├── pre-run.json       # Pre-phase hook outputs (array)
            │   ├── command.json       # Command execution results
            │   └── post-run.json      # Post-phase hook outputs (array)
            └── [captured files]       # Files copied by file hooks

metadata.json contains run information:

{
  "id": "01K8WSYC91YAE21R7CWHQ4KYN2",
  "name": "chubby-back",
  "command": ["echo", "hello"],
  "timestamp": "2025-10-31T09:35:25.473+00:00",
  "run_dir": "/path/to/.capsula/vault-name/2025-10-31/093525-chubby-back"
}

command.json contains command execution results:

{
  "exit_code": 0,
  "stdout": "hello\n",
  "stderr": "",
  "duration": {
    "secs": 0,
    "nanos": 1986042
  }
}

License

This project is licensed under either of the MIT license or the Apache License 2.0 at your option.

capsula-core 0.9.2

Capsula

Features

Installation / Update

Install from crates.io (recommended)

Install from the GitHub repository

Quick Start

Configuration

Basic Structure

Available Hook Types

Git Hook

Current Working Directory

File Hook

Environment Variables Hook

Command Hook

Machine Hook

Slack Notification Hook

CLI Usage

Commands

capsula run <command>

capsula list

Output Structure

Metadata

Vault Structure

License

`capsula run <command>`

`capsula list`