takopi-preview 0.1.12

Tailscale preview command plugin for Takopi

takopi-preview

preview command plugin for takopi. starts a dev server (optional), exposes it via tailscale serve, and tracks preview sessions by project/worktree context.

published as the takopi-preview package. the command id is preview.

features

• /preview commands to start, list, stop, and clean up previews
• per-project overrides for ports and dev commands
• optional dev server auto-start with {port} substitution
• session registry with ttl expiration
• allowlist support for sensitive commands (like killall)

requirements

• python 3.14+
• takopi >= 0.20
• provider tooling:
  • tailscale installed and authenticated on the host (tailscale up)
• dev server binds to 127.0.0.1 (tunnels proxy locally)
• security groups should not expose the dev server port publicly

install

install into the same environment as takopi.

uv tool install -U takopi
uv tool install -U takopi --with takopi-transport-slack --with takopi-preview

or, with a virtualenv:

pip install takopi-transport-slack takopi-preview

setup

1. install tailscale and authenticate (tailscale up).
2. enable magicdns so DEVICE.TAILNET.ts.net resolves.
3. run takopi with your transport (slack or telegram) as usual.

configuration

add to ~/.takopi/takopi.toml:

[plugins]
enabled = ["takopi-transport-slack", "takopi-preview"]

[plugins.preview]
provider = "tailscale"
default_port = 3000
dev_command = "pnpm dev -- --host 127.0.0.1 --port {port}"
auto_start = true
ttl_minutes = 120
path_prefix = "/preview"
allowed_user_ids = [123456789]

# optional env injection for the dev server
[plugins.preview.env]
NODE_ENV = "development"

# advanced overrides
local_host = "127.0.0.1"
path_prefix = "/preview"

# tailscale-specific
tailscale_bin = "tailscale"

# per-project overrides (Takopi project tables are strict, so use plugins.preview.projects)
[plugins.preview.projects.myapp]
port = 5173
dev_command = "npm run dev -- --host 127.0.0.1 --port {port}"

notes:

• provider = "tailscale" uses tailnet-only urls from tailscale serve.
• dev_command may include {port}; it will be substituted at runtime.
• dev_command is required when auto_start = true. set auto_start = false to manage the dev server yourself.
• Inline --dev/-- overrides enable auto-start for that run; use --no-start to force manual mode.
• To require an explicit command each run, omit dev_command and set auto_start = false, then pass --dev or --.
• ttl_minutes = 0 disables expiration.
• empty allowed_user_ids means no allowlist enforcement.

commands

• /preview start [port]: start a preview for the current context
• /preview start [port] --dev "<command>": override the dev command for this run
• /preview start [port] -- <command>: shorthand for an inline dev command
• /preview list: show active previews (url, port, uptime, context)
• /preview stop [id|port]: stop a preview (defaults to current context)
• /preview killall: stop all previews (restricted by allowlist)
• /preview help: usage help

workflow

1. choose a context: /myapp @feat/login or reply in an existing thread. previews only run in worktrees, so include a branch to create/use one.
2. run /preview start (or /preview start 5173).
3. open the returned url, for example:

https://DEVICE.TAILNET.ts.net/preview/5173

4. stop when done: /preview stop or /preview stop 5173.

state and ttl

• tailscale: sessions are derived from tailscale serve status; no preview state file is written.
• tailscale: if the requested port is already served, takopi will attempt to disable the existing serve entry before starting a new preview.
• tailscale: set path_prefix = "/" to serve from the tailnet root. This avoids subpath issues with apps that assume /, but only one preview can be served at a time.

dev server logs (when auto-started) are written to:

• ~/.takopi/state/preview-logs/<session>.log

ttl_minutes controls automatic expiration for previews started by this takopi process; expired sessions are cleaned up on the next command invocation. worktrees that are pruned or deleted are also cleaned up on the next command. takopi shutdown stops all previews.

errors

• missing tailscale: follow the install docs and run tailscale up.
• serve disabled: enable serve for your tailnet (Tailscale admin UI) if you see the "Serve is not enabled" error.
• port already in use: when auto-starting, takopi will try to stop listeners on that port; if it is still busy, run /preview list or pick a new port.
• not in a worktree: include a branch (ex: /myapp @feat/foo) to create/use a worktree.
• dev server failures: the error includes log tail + log path.

spec alignment

this implementation follows the webapp preview workflow spec:

• command surface: start/list/stop/killall/help
• config in [plugins.preview] with per-project overrides
• tailscale serve for tailnet-only preview urls
• tailscale serve registry
• ttl-based expiration (ttl_minutes)
• allowlist enforcement via allowed_user_ids

license

mit