looker-assessment

name	looker-assessment
description	Take inventory of a Looker instance and produce a migration-readiness readout — model / explore / project / connection (dialect) / Look / dashboard (UDD vs LookML) / user / group / folder counts, per-dashboard complexity (vis-type mix, pivots, table calcs, merged results, custom viz, Liquid, filters), usage from Looker's System Activity model, and a value/cost-ranked migration shortlist. Use to scope a Looker→Sigma migration or audit BI sprawl. Looker REST API 4.0 driven (read-only); hands off to looker-to-sigma.
user-invocable	true

Looker Assessment

STATUS: working inventory (Looker REST API 4.0 driven, live-validated on hakkoda1.cloud.looker.com). Mirrors tableau-assessment / qlik-assessment: same value / (1 + cost) scoring, same migrate-first / easy-win / moderate / needs-gap-scout / retire tags, and the byte-identical Sigma-branded HTML readout theme.

Read first:

• refs/complexity-scoring.md — the Looker convertibility rubric (vis-type + feature buckets)
• refs/output-shapes.md — exact inventory.json shape the renderer consumes
• ../looker-to-sigma/SKILL.md — the conversion skill this feeds into; auth recipe
• PRIVACY.md — read-only posture

The key idea

The same translation rules that drive convert_lookml_to_sigma + the dashboard builder (../looker-to-sigma/scripts/build_workbook.py) also predict migration effort: bucket each dashboard tile's vis-type and hard-to-migrate features against Sigma's coverage. Pivots / table calcs / Liquid → manual (a brief post-conversion step in Sigma); merged results / marketplace-or-custom viz → unhandled (no direct Sigma equivalent — review). Usage (the value axis) comes from Looker's own System Activity model, which Looker exposes well (unlike most BI tools where usage telemetry is the weak spot).

Read-only. Only GETs and System Activity inline queries (POST /queries/run/json against model: system__activity). No object is created, edited, or deleted; no warehouse content query is ever run.

UDD and LookML dashboards convert through the same path. GET /dashboards/{id} returns user-defined (UI-built) and LookML dashboards as the same JSON shape, so the assessment treats them identically and just records the kind for reporting. UDD is the primary path.

Auth & environment

Looker API3 credentials in ~/.looker/looker.ini:

[Looker]
base_url=https://<host>.cloud.looker.com:19999
client_id=...
client_secret=...
verify_ssl=true

The :19999 API port matters (login there returns the bearer). scripts/looker_api.py (copied in for self-containment) reads the ini and logs in fresh per call. Confirm access with python3 scripts/looker_api.py whoami. Most counts need only a normal role; the System Activity queries need a role with permission to the system__activity model (admin or a role granted see_system_activity) — if that permission is missing, usage falls back to 0 and dashboards score on a tile-count proxy. Point at a different ini with --ini PATH.

Phases

0. Probe — python3 scripts/looker_api.py whoami confirms auth + role. A System Activity test query confirms usage access (the inventory script degrades gracefully to proxy scoring if it's denied).
1. Environment counts — GET /lookml_models (+ explores rolled up), /projects, /connections (dialects), /looks, /dashboards, /folders, /groups, /users. Dashboards split UDD vs LookML by id shape (model::name = LookML).
2. Usage (System Activity) — POST /queries/run/json on system__activity: the history explore grouped by dashboard.id/look.id for run counts over the last N days, and a totals query for user.count (active users) + query/dashboard run volume. See refs/complexity-scoring.md for the exact field list.
3. Per-dashboard complexity — GET /dashboards/{id} per dashboard; bucket each tile's vis-type and detect pivots (query.pivots), table calcs (query.dynamic_fields, a JSON string), merged results (merge_result_id), custom/marketplace viz (vis type outside the known set), and Liquid ({{ }} / {% %} in the query). Count filters.
4. Shortlist — cost = 10·unhandled + 3·manual + 1·hint; value = dashboard_runs × √query_runs (tile-count proxy when cold); score = value / (1 + cost); tag.
5. Readout — looker-inventory.py writes inventory.json + readout.md; then render-readout-html.rb --out <dir> renders the customer-facing, Sigma-branded readout.html (same theme as tableau-assessment / qlik-assessment).
6. Hand off — to looker-to-sigma (ask the user which dashboards first).

How to run

# one pass: counts + System Activity usage + per-dashboard complexity + shortlist
python3 scripts/looker-inventory.py --out /tmp/assessment-<host> --usage-days 90
ruby   scripts/render-readout-html.rb --out /tmp/assessment-<host>

Flags:

• --out DIR — output dir (default assessment-<host>).
• --usage-days N — System Activity window (default 90); surfaced in the readout.
• --no-deep — skip the per-dashboard GET /dashboards/{id} scan (counts + usage only; the shortlist falls back to usage-only). Useful for a fast first pass or when there are hundreds of dashboards.
• --ini PATH — alternate looker.ini.

Scripts

Script	Phase	Purpose
scripts/looker_api.py	all	Minimal Looker API 4.0 client (copied from looker-to-sigma for self-containment; reads ~/.looker/looker.ini, logs in fresh per call).
scripts/looker-inventory.py	1–4	Enumerate the environment, pull System Activity usage, scan per-dashboard complexity, score + tag → inventory.json + readout.md. Reuses the same tile/feature normalization as looker-to-sigma's fetch_looker_dashboard.py.
scripts/render-readout-html.rb	5	Render the Sigma-branded readout.html from inventory.json.

Deliverables (in <out>/)

• inventory.json — environment counts, connection dialects, System Activity usage, per-dashboard complexity buckets, ownership rollup, feature/viz rollups, and the value/cost-ranked shortlist. The single file the renderer + looker-to-sigma consume.
• readout.md — compact markdown summary (written by the Python script).
• readout.html — customer-facing, Sigma-branded HTML report. Open in a browser or print to PDF to share.

Nothing in this directory is uploaded anywhere — sharing is a deliberate action.

Live validation

Validated end-to-end against hakkoda1.cloud.looker.com (Looker 26.8.11) on 2026-06-10: 6 models / 29 explores / 5 projects / 3 Snowflake connections / 1 Look / 8 dashboards (all UDD) / 13 folders / 3 groups. System Activity over 90 days returned real run counts (Snowflake Operations = 22 dashboard runs / 43 queries → top of the shortlist as migrate-first; Orders Overview = 2 runs / 18 queries) and 2 active users. Per-dashboard scan correctly flagged Orders Deep Dive's pivot + table-calc tiles as manual.

Hand off to looker-to-sigma

After the readout, present the user a choice (which dashboards to migrate first) and invoke looker-to-sigma with the shortlisted dashboard ids — the converter handles the LookML model (convert_lookml_to_sigma) and rebuilds each dashboard from its Looker Dashboard API JSON. The shortlist array in inventory.json is the hand-off contract.

Open work

• Per-tile usage is dashboard-level; the System Activity history explore can also break out by query.id/dashboard_element for tile-level attention if needed.
• Folder/group ACL audit (who can see what) is out of scope — counts only.
• Large instances (hundreds of dashboards): use --no-deep for the first pass, then deep-scan only the usage-ranked top slice.