4.1 mConfig Tool (`mconfig`)

The mconfig tool provides a command-line interface for inspecting and managing configurations. It allows you to list available configurations, show effective values, get detailed metadata for specific keys, search for configuration paths, and more.

4.1.1 Installation

The tool is available as a "fat JAR" in the mConfigTools module. You can run it using:

java -jar mConfigTools-*.jar [OPTIONS] [COMMAND] [COMMAND_OPTIONS]

4.1.2 Subcommands

list: List all available configurations for the given company and application.
show: Print the effective configuration (all keys and values).
get: Show detailed information for a specific key (value, type, source URI, scope, and description).
search-paths: List all directories and storage locations where mConfig looks for files.
propose-scheme: Generate a draft ConfigScheme JSON from an existing configuration.
validate: Validate a configuration against its scheme.
set: Set or update a configuration entry. Requires --value and --scope.
monitor: Monitor a configuration for real-time changes. Keeps running until interrupted.

4.1.2.1 `set` command options:

-V, --value=<value>: The value to set.
-S, --scope=<scope>: Target ConfigScope (USER, HOST, SESSION, RUNTIME, etc.).
-T, --type=<type>: ConfigEntryType (optional, inferred from scheme if available).
-d, --dry-run: Display what would be changed without performing the actual write.

4.1.2.2 `monitor` command options:

--dump: Print the full effective configuration before starting the monitor loop.
-v, --verbose: Provide more detail about changes (e.g., the scope of the change).

4.1.3 Global Options and Commands

Options can be placed both before and after the command (verb).

-c, --company=<name>: Company name (default: MCONFIG_COMPANY env var). Use "" (empty string) intentionally to omit the company segment in all paths/sources (e.g., ~/.config/myapp/).
-a, --app=<name>: Application name (default: MCONFIG_APP env var)
-C, --config=<name>: Configuration name (default: MCONFIG_CONFIG env var)
-k, --key=<name>: Specific configuration key
-o, --output=<format>: Output format (HUMAN, JSON, CSV)
-v, --verbose: Enable verbose output (shows source URIs and scopes)
-l, --lang=<lang>: Preferred language for descriptions (default: en)

Do not underestimate the power of "-v" verbose mode! Try it and see which extra information you can get out of it.

4.1.4 Shortened Syntax

For quick interactive use, the tool supports a positional argument in the format: [COMPANY:]APPLICATION[:CONFIGNAME[:KEY]] where COMPANY can be empty "" to omit the company segment in paths (use leading : e.g. :myapp:settings).

Examples: - mconfig mycompany:myapp:database show (with company) - mconfig :myapp:database show (app-only) Both equivalent to mconfig --company [""""] --app myapp --config database show.

4.1.5 Environment Variables

The tool automatically picks up the following environment variables if the corresponding options are not provided: - MCONFIG_COMPANY - MCONFIG_APP - MCONFIG_CONFIG

4.1.6 Examples

List configurations:

mconfig --company mycomp --app myapp list

Show effective configuration:

mconfig mycomp:myapp:settings show
# OR
mconfig show --company mycomp --app myapp --config settings

Get value and metadata for a specific key:
```
mconfig mycomp:myapp:db:password get
```

Change output to JSON for scripting:

mconfig mycomp:myapp:settings show -o JSON

See where the values in your configuration are coming from:
```
mconfig mycomp:myapp:settings show -v
```

Set a configuration value:

mconfig mycomp:myapp:db:user set --value="dbuser" --scope=USER

Update a configuration value with dry-run and validation:

mconfig mycomp:myapp:settings:timeout set -V 30 -S HOST -T NUMBER --dry-run

Monitor configuration changes: This one's for you, SRE and developers!

mconfig mycomp:myapp:settings monitor --dump -v
mconfig :myapp:settings monitor --dump -v  # app-only

App-only examples (omit company segment):

mconfig -c "" myapp list
mconfig :myapp:db get password

4.1 mConfig Tool (mconfig)