Add JSON Output to List Command

[josecelano]

Overview

Implements JSON output format for the list command, completing Phase 1 of EPIC #348 (JSON Output for High-Value Commands).

Closes: #359
Part of: #348 - Add JSON output format support

Changes

1. JSON Output Implementation

• New: JsonView in src/presentation/views/commands/list/views/json_view.rs
  • Serializes EnvironmentList to pretty-printed JSON
  • Includes all environment data without truncation
  • Handles failed environments gracefully
  • 5 comprehensive unit tests

2. DTO Serialization Support

• Modified: src/application/command_handlers/list/info.rs
  • Added #[derive(Serialize)] to EnvironmentSummary and EnvironmentList
  • Enables JSON serialization via serde

3. Controller Updates

• Modified: src/presentation/controllers/list/handler.rs
  • Updated execute() to accept OutputFormat parameter
  • Implements Strategy Pattern in display_results() (TextView or JsonView)

4. Router Integration

• Modified: src/presentation/dispatch/router.rs
  • Extracts output_format from ExecutionContext
  • Passes format to ListCommandController

5. Module Structure

• Modified: src/presentation/views/commands/list/mod.rs
  • Re-exports both TextView and JsonView

6. Text View Enhancement

• Modified: src/presentation/views/commands/list/views/text_view.rs
  • Increased environment name column width from 20 to 50 characters
  • Updated table separator width accordingly
  • Fixed truncation test expectations

Usage

Text Output (Default)

torrust-tracker-deployer list
# or explicitly:
torrust-tracker-deployer list --output-format text

JSON Output

torrust-tracker-deployer list --output-format json

JSON Schema Example

{
  "environments": [
    {
      "name": "production-high-availability-tracker",
      "state": "Running",
      "provider": "Hetzner Cloud",
      "created_at": "2026-02-14T16:45:00Z"
    }
  ],
  "total_count": 1,
  "failed_environments": [],
  "data_directory": "/path/to/data"
}

Benefits

• No Truncation: JSON output provides full environment names (text format now shows 50 chars before truncating)
• Automation Ready: Easy parsing with jq or programming languages
• Complete Data: Includes all fields (name, state, provider, created_at)
• Failure Handling: Failed environments included separately in JSON
• Backward Compatible: Text output unchanged as default format

Automation Examples

# Extract all environment names
torrust-tracker-deployer list -o json | jq -r '.environments[].name'

# Filter by state
torrust-tracker-deployer list -o json | jq -r '.environments[] | select(.state == "Running") | .name'

# Count by provider
torrust-tracker-deployer list -o json | jq '.environments | group_by(.provider) | map({provider: .[0].provider, count: length})'

Testing

• ✅ All 2,254 tests passing (including 5 new JsonView tests)
• ✅ All linters passing (markdown, yaml, toml, cspell, clippy, rustfmt, shellcheck)
• ✅ Build successful

Architecture

Follows the established Strategy Pattern from previous JSON output implementations:

• Add JSON Output to create Command #349 (create command) ✅
• Add JSON output to provision command #352 (provision command) ✅
• Add JSON output to show command #355 (show command) ✅
• Add JSON output to run command #357 (run command) ✅
• Add JSON Output to List Command #359 (list command) ✅ ← This PR

This completes Phase 1 of the JSON output support epic.

[josecelano]

ACK 181db29