$ Architecture
Pipeline
tgdash processes Terragrunt output through a pipeline:
stdin -> reader -> parser -> processor -> state -> TUI
Packages
| Package | Role |
|---|---|
runner | Spawns commands in exec mode |
reader | Reads stdin, emits Bubble Tea msgs |
parser | Regex: prefix, plan, apply, errors |
processor | Routes parsed lines into AppState |
state | Unit model, run history |
estimator | Time estimates from past runs |
tui | Bubble Tea views and keybindings |
integration | Fixture-based integration tests |
How it works
Runner
In exec mode (tgdash -- command), the runner spawns
the child process and provides its output as a reader.
It also detects the Terragrunt command (plan, apply,
etc.) from the arguments.
Reader
The reader goroutine reads lines from the input source (stdin in pipe mode, or the child process in exec mode) and sends them as Bubble Tea messages to the TUI. This allows the TUI to remain responsive while processing input.
Parser
Each line is parsed with regex to extract:
- Unit prefix - The
[unit/path]at the start - Plan summary - Lines matching
Plan: N to add, N to change, N to destroy - Apply result - Lines matching
Apply complete! Resources: ... - Errors - Terraform error blocks
Processor
The processor takes parsed lines and updates the application state. It tracks which units exist, their current status, and accumulates output per unit.
State
AppState holds the full model: list of units, their statuses, plan summaries, errors, and output lines. Units progress through states: waiting, running, done, or error.
Estimator
The estimator uses historical run data (stored in
~/.local/share/tgdash/history.json) to predict how
long each unit will take based on past runs.
TUI
Built with Bubble Tea, the TUI renders the dashboard and list views, handles keybindings, and updates in real-time as new messages arrive.