Design system¶

Every usm command — the launcher and the scripts it runs — renders through usmo.ui, so twenty-seven separate programs read as one tool.

from usmo.ui import Column, detail, ok, table

The vocabulary¶

	meaning
`✓`	something finished
`✗`	something failed
`!`	worth reading, but not fatal
`→`	a step starting, or a transition (`old → new`)
`●` `○`	present / absent — cached, mounted, enabled, running
`·`	separator between facts on one line

Colour carries the same meaning everywhere:

	used for
bold cyan	an identifier you could type back: a name, an id
dim	context you can skip: paths, counts, hints
green / yellow / red	the three status levels

Nothing else is coloured. If a value isn't an identifier, a status or context, it stays plain.

ui.RUNNING / ui.STOPPED are the same two glyphs under the names a daemon reads better with; a table uses the glyph (ui.state) and a detail row uses the word (ui.status_text), and both take their colour from the same place.

Status lines¶

ui.ok("mounted ~/data")             # ✓ mounted ~/data
ui.warn("SAS expires in 12m")       # ! SAS expires in 12m       (stderr)
ui.fail("mount failed")             # ✗ mount failed             (stderr)
ui.step("refreshing credential")    # → refreshing credential
ui.hint("usm azsync ls to see all") # dim, secondary guidance
ui.title("azsync", subtitle="4 syncs")

fail and warn go to stderr so a command's result stays pipeable.

Everything is redacted on the way out — sig=, password=, token=, api-key= and friends become ***. A credential cannot reach a terminal or a log just because someone interpolated a URL into a message.

Tables¶

Headers are lowercase: they are dim context, not titles, and shouting them competes with the bold-cyan identifiers in the rows. Short acronyms (SAS, TCP, SSH) keep their case because lowercasing them makes them harder to read, not easier.

A listing row is one line. Columns are dropped as the terminal narrows rather than every column being squeezed into uselessness — the detail view always has the full picture.

built = ui.table(
    ui.Column("id", min_width=6),
    ui.Column("source", hide_below=110),      # first to go
    ui.Column("destination", min_width=14, ratio=1),
    ui.Column("SAS", justify="right", hide_below=80),
    title="Syncs",
)

A table stops at its content, not at the right margin — a rule trailing off across a wide window reads as a stray line, not as a table. It grows to at most ui.MAX_TABLE_WIDTH (96) columns; past that the ratio column takes the squeeze on its own, so identifiers and states stay readable while only the long path or description ellipsizes. Pass max_width= for a different cap, or expand=True for the rare table that really should fill the width.

hide_below is the terminal width under which a column disappears. Build rows to match with ui.row_for, keyed by header:

for job in jobs:
    built.add_row(*ui.row_for(columns, {
        "ID": job.id,
        "Source": ui.shorten_path(job.source),
        "Destination": ui.short_blob_target(job.dest),
        "SAS": ui.compact_duration(remaining),
    }))

Detail views¶

The inverse: values wrap rather than truncate, because silently cutting a path in half is worse than a second line. Group with SECTION.

ui.print_detail([
    ("source", ui.shorten_path(job.source)),
    ("destination", ui.short_blob_target(job.dest)),
    ui.SECTION,
    ("status", ui.status("ok", "watching")),
    ("last sync", "ok, 2m ago"),
])

source       ~/data
destination  acct/research/exports

status       watching
last sync    ok, 2m ago

Formatting¶

Two duration formats, deliberately:

		for
`human_duration(9000)`	`2h30m`	detail views, where width is free
`compact_duration(9000)`	`2h`	table columns — never more than 4 chars

Using the precise one in a column is what makes a row wrap to three lines.

helper
`human_bytes`	`2.0KiB`, `5.0MiB`
`shorten_path`	`/home/first.last@example.com/data` → `~/data`
`short_blob_target`	`https://acct.blob.core.windows.net/c/a?sas` → `acct/c/a`
`elide(text, n)`	trims, keeping the tail (paths are known by their end)
`plural(2, "sync")`	`2 syncs`
`joined(a, b, c)`	`a · b · c`

Adopting it in a script¶

Declare usmo in the script's requirements:

"myscript": {
  "path": "myscript.py",
  "requirements": ["click>=8.2.1", "usmo>=0.11.0"]
}

Then import it like any library. usm --debug myscript installs the usmo checkout you're standing in editably, so changes to the design system take effect immediately — no release, no venv rebuild.

Cost¶

usmo.ui imports only the standard library; rich is pulled in the first time something is actually rendered. A command that prints two status lines never pays for the table engine. Column is a plain class rather than a dataclass for the same reason — dataclasses alone costs ~9ms, and this module is imported on every usm invocation.

Source¶

src/usmo/ui.py, tested at 100% line coverage in tests/test_ui.py — including that the glyphs don't drift, that secrets never render, that a row fits terminals from 50 to 200 columns, and that importing the module doesn't drag in rich.