fix(fw): rebuild electricity price sensor on epex_spot 4.x with full fee model + future-price chart #218

Merged

dominik.polakovics merged 1 commit from afk/217 into main

2026-07-05 18:24:09 +02:00

dominik.polakovics commented

2026-07-05 17:46:50 +02:00

Owner

Closes #217

What changed

hosts/fw/modules/home-assistant/electricity.nix:

sensor.electricity_price (entity id unchanged) is now a modern template: sensor sourced from sensor.epex_spot_data_market_price (the epex_spot 4.x entity). State = (market_price + fees_net) × 1.20, guarded by an availability template so a missing source makes the entity unavailable instead of raising TemplateError on every render.
Fee model as named let constants, one per line of the June 2026 Spotty invoice (Σ ≈ 0.1010 net €/kWh), VAT 20% as the final multiplier. The 2027 Elektrizitätsabgabe revert (0.0010 → 0.015) is a one-line edit.
sensor.electricity_price_forecast exposes a forecast attribute: [{start, price}, …] consumer prices for the current + all future intervals from the source's data attribute (start_time/end_time/price_per_kwh, resolution-agnostic — works for hourly and 15-min). The entity is excluded from the recorder via recorder.exclude.entities.
apexcharts-card (v2.2.3 from nixos-26.05, verified) installed declaratively via services.home-assistant.customLovelaceModules — auto-registers as a Lovelace resource.

Deviation from the acceptance criteria (deliberate)

The criteria asked for the forecast attribute on sensor.electricity_price itself, excluded from the recorder. That is not implementable on HA 2026.5.4 — verified from the 2026.5.4 source: the recorder's exclude config is entity-level only (entities/entity_globs/domains/event_types), and the template integration has no recorder.py platform and no unrecorded-attributes config option. The brief said "recorder.exclude config or template attribute exclusion — whichever HA 2026.5 supports for attributes"; it supports neither.

Options were: (a) put the attribute on sensor.electricity_price and exclude that whole entity — loses its state history and long-term statistics; (b) let the attribute be recorded — ~96 attribute rows/day × up to ~192 entries, the exact DB bloat the issue wants to avoid; or (c) a dedicated sensor.electricity_price_forecast carrying the attribute, wholly recorder-excluded. I picked (c): zero DB bloat and sensor.electricity_price keeps recording clean price history. If you prefer letter-perfect (a), it's a small diff — move the attributes.forecast block over and swap the excluded entity id.

Template validation

Both Jinja templates were validated against a simulated HA environment (HA-style strip + literal_eval, stubbed state_attr/has_value/as_datetime/now, fake 15-min data with past/current/future entries): state math is exact, past intervals are dropped, current interval is kept, output is a native list of {start, price} dicts, and an unavailable source degrades to [] / unavailable without errors.

ApexCharts card YAML (paste into a dashboard via UI, storage mode)

type: custom:apexcharts-card
header:
  show: true
  title: Electricity price (incl. grid fees + 20% VAT)
  show_states: true
  colorize_states: true
graph_span: 36h
span:
  start: hour
now:
  show: true
  label: now
yaxis:
  - min: 0
    decimals: 2
series:
  - entity: sensor.electricity_price
    name: Current price
    unit: EUR/kWh
    show:
      in_header: true
      in_chart: false
  - entity: sensor.electricity_price_forecast
    name: Consumer price
    unit: EUR/kWh
    type: column
    show:
      in_header: false
      legend_value: false
    data_generator: |
      return entity.attributes.forecast.map((e) => [new Date(e.start).getTime(), e.price]);
    color_threshold:
      - value: 0
        color: '#2ecc71'
      - value: 0.22
        color: '#f1c40f'
      - value: 0.28
        color: '#e67e22'
      - value: 0.35
        color: '#e74c3c'
  # Optional overlay: raw spot price, visualizes the fee/tax wedge
  - entity: sensor.epex_spot_data_market_price
    name: Raw spot (net)
    unit: EUR/kWh
    type: line
    curve: stepline
    show:
      in_header: false
      legend_value: false
    data_generator: |
      return entity.attributes.data.map((e) => [new Date(e.start_time).getTime(), e.price_per_kwh]);

Notes: the forecast only carries current + future intervals, so the chart starts "now" (span.start: hour); tomorrow's bars appear after day-ahead publication (~14:00). The raw-spot overlay reads the source sensor's own data attribute, so it also shows today's past hours.

Post-merge verification (human follow-ups per the brief)

After bento pulls (~5 min) and HA restarts: confirm sensor.electricity_price tracks (market + 0.101) × 1.2 and the TemplateError ... float got invalid input 'unavailable' no longer recurs in the hass container journal (journalctl -D /var/lib/nixos-containers/hass/var/log/journal on fw, per ADR-0005).
Confirm actual interval resolution (hourly vs 15-min) in Developer Tools → States; the mapping works for either.
Paste the card YAML above onto a dashboard; delete the orphaned sensor.epex_spot_data_price / sensor.epex_spot_data_net_price registry entries (cosmetic).

Pre-commit dry-build for fw: green.

Closes #217 ## What changed `hosts/fw/modules/home-assistant/electricity.nix`: - **`sensor.electricity_price`** (entity id unchanged) is now a **modern `template:` sensor** sourced from `sensor.epex_spot_data_market_price` (the epex_spot 4.x entity). State = `(market_price + fees_net) × 1.20`, guarded by an `availability` template so a missing source makes the entity *unavailable* instead of raising `TemplateError` on every render. - **Fee model** as named `let` constants, one per line of the June 2026 Spotty invoice (Σ ≈ 0.1010 net €/kWh), VAT 20% as the final multiplier. The 2027 Elektrizitätsabgabe revert (0.0010 → 0.015) is a one-line edit. - **`sensor.electricity_price_forecast`** exposes a `forecast` attribute: `[{start, price}, …]` consumer prices for the current + all future intervals from the source's `data` attribute (`start_time`/`end_time`/`price_per_kwh`, resolution-agnostic — works for hourly and 15-min). The entity is excluded from the recorder via `recorder.exclude.entities`. - **`apexcharts-card`** (v2.2.3 from nixos-26.05, verified) installed declaratively via `services.home-assistant.customLovelaceModules` — auto-registers as a Lovelace resource. ## Deviation from the acceptance criteria (deliberate) The criteria asked for the `forecast` attribute **on `sensor.electricity_price` itself**, excluded from the recorder. That is not implementable on HA 2026.5.4 — verified from the 2026.5.4 source: the recorder's `exclude` config is entity-level only (`entities`/`entity_globs`/`domains`/`event_types`), and the template integration has no `recorder.py` platform and no unrecorded-attributes config option. The brief said "recorder.exclude config or template attribute exclusion — whichever HA 2026.5 supports for attributes"; it supports **neither**. Options were: (a) put the attribute on `sensor.electricity_price` and exclude that whole entity — loses its state history and long-term statistics; (b) let the attribute be recorded — ~96 attribute rows/day × up to ~192 entries, the exact DB bloat the issue wants to avoid; or (c) a dedicated `sensor.electricity_price_forecast` carrying the attribute, wholly recorder-excluded. I picked **(c)**: zero DB bloat *and* `sensor.electricity_price` keeps recording clean price history. If you prefer letter-perfect (a), it's a small diff — move the `attributes.forecast` block over and swap the excluded entity id. ## Template validation Both Jinja templates were validated against a simulated HA environment (HA-style strip + literal_eval, stubbed `state_attr`/`has_value`/`as_datetime`/`now`, fake 15-min `data` with past/current/future entries): state math is exact, past intervals are dropped, current interval is kept, output is a native list of `{start, price}` dicts, and an unavailable source degrades to `[]` / unavailable without errors. ## ApexCharts card YAML (paste into a dashboard via UI, storage mode) ```yaml type: custom:apexcharts-card header: show: true title: Electricity price (incl. grid fees + 20% VAT) show_states: true colorize_states: true graph_span: 36h span: start: hour now: show: true label: now yaxis: - min: 0 decimals: 2 series: - entity: sensor.electricity_price name: Current price unit: EUR/kWh show: in_header: true in_chart: false - entity: sensor.electricity_price_forecast name: Consumer price unit: EUR/kWh type: column show: in_header: false legend_value: false data_generator: | return entity.attributes.forecast.map((e) => [new Date(e.start).getTime(), e.price]); color_threshold: - value: 0 color: '#2ecc71' - value: 0.22 color: '#f1c40f' - value: 0.28 color: '#e67e22' - value: 0.35 color: '#e74c3c' # Optional overlay: raw spot price, visualizes the fee/tax wedge - entity: sensor.epex_spot_data_market_price name: Raw spot (net) unit: EUR/kWh type: line curve: stepline show: in_header: false legend_value: false data_generator: | return entity.attributes.data.map((e) => [new Date(e.start_time).getTime(), e.price_per_kwh]); ``` Notes: the forecast only carries current + future intervals, so the chart starts "now" (`span.start: hour`); tomorrow's bars appear after day-ahead publication (~14:00). The raw-spot overlay reads the source sensor's own `data` attribute, so it also shows today's past hours. ## Post-merge verification (human follow-ups per the brief) - After bento pulls (~5 min) and HA restarts: confirm `sensor.electricity_price` tracks `(market + 0.101) × 1.2` and the `TemplateError ... float got invalid input 'unavailable'` no longer recurs in the hass container journal (`journalctl -D /var/lib/nixos-containers/hass/var/log/journal` on fw, per ADR-0005). - Confirm actual interval resolution (hourly vs 15-min) in Developer Tools → States; the mapping works for either. - Paste the card YAML above onto a dashboard; delete the orphaned `sensor.epex_spot_data_price` / `sensor.epex_spot_data_net_price` registry entries (cosmetic). Pre-commit dry-build for fw: green.

dominik.polakovics added 1 commit

2026-07-05 17:46:50 +02:00

fix(fw): rebuild electricity price sensor on epex_spot 4.x with full fee model 9d6def06f8

The epex_spot 4.x rename orphaned sensor.epex_spot_data_price, leaving
sensor.electricity_price erroring on every render (float on
'unavailable' raises since HA 2021.10 without a default). The old
formula also never applied 20% VAT.

Rebuild it as a modern template: sensor sourced from
sensor.epex_spot_data_market_price, with the Spotty fee model as named
constants (one per invoice line) and VAT as the final multiplier. Add a
recorder-excluded sensor.electricity_price_forecast carrying consumer
prices for all remaining intervals, and install apexcharts-card via
customLovelaceModules for the future-price chart.

Closes #217

dominik.polakovics commented

2026-07-05 18:23:06 +02:00

Author

Owner

This was generated by AI while landing a PR.

Land-PR audit — verdict: PASS

Checked:

State: open, not draft, no conflicts with main.
Verification signal relied on: the repo's commit-time gate (pre-commit dry-build of fw, per CLAUDE.md), which the PR reports green. Not re-run. The diff changes no derivation src/hash, so the gate's eval-only blind spot does not apply — the referenced nixpkgs attr home-assistant-custom-lovelace-modules.apexcharts-card is itself eval-checked.
Conventions: Conventional Commit title with host scope (fix(fw):) ✓; no secrets edits, no system.stateVersion change.
AFK contract: head afk/217 carries a working Closes #217 ✓.
Diff review vs issue #217 intent: source entity, fee constants (Σ = 0.1010 net, invoice-commented, 2027 Abgabe revert is one line), VAT as final multiplier, modern template: syntax, entity id sensor.electricity_price preserved, availability guard replaces the old TemplateError failure mode. The triage-resolved price key (price_per_kwh, ISO start_time/end_time) matches the forecast mapping exactly. Nix float splicing verified: toString renders 0.101000 / 1.200000 — valid Jinja literals.

Noted deviation (deliberate, accepted): the forecast attribute lives on a dedicated sensor.electricity_price_forecast (wholly recorder-excluded) rather than on sensor.electricity_price, because HA 2026.5 supports neither attribute-level recorder exclusion nor template unrecorded-attributes. Option (c) preserves price history with zero DB bloat and was explicitly justified in the PR body.

> *This was generated by AI while landing a PR.* ## Land-PR audit — verdict: PASS **Checked:** - State: open, not draft, no conflicts with `main`. - Verification signal relied on: the repo's commit-time gate (pre-commit dry-build of fw, per CLAUDE.md), which the PR reports green. Not re-run. The diff changes no derivation `src`/hash, so the gate's eval-only blind spot does not apply — the referenced nixpkgs attr `home-assistant-custom-lovelace-modules.apexcharts-card` is itself eval-checked. - Conventions: Conventional Commit title with host scope (`fix(fw):`) ✓; no secrets edits, no `system.stateVersion` change. - AFK contract: head `afk/217` carries a working `Closes #217` ✓. - Diff review vs issue #217 intent: source entity, fee constants (Σ = 0.1010 net, invoice-commented, 2027 Abgabe revert is one line), VAT as final multiplier, modern `template:` syntax, entity id `sensor.electricity_price` preserved, availability guard replaces the old TemplateError failure mode. The triage-resolved price key (`price_per_kwh`, ISO `start_time`/`end_time`) matches the forecast mapping exactly. Nix float splicing verified: `toString` renders `0.101000` / `1.200000` — valid Jinja literals. **Noted deviation (deliberate, accepted):** the `forecast` attribute lives on a dedicated `sensor.electricity_price_forecast` (wholly recorder-excluded) rather than on `sensor.electricity_price`, because HA 2026.5 supports neither attribute-level recorder exclusion nor template unrecorded-attributes. Option (c) preserves price history with zero DB bloat and was explicitly justified in the PR body.

dominik.polakovics merged commit c3e641a50b into main

2026-07-05 18:24:09 +02:00

dominik.polakovics referenced this pull request from a commit

2026-07-05 18:24:09 +02:00

Merge pull request 'fix(fw): rebuild electricity price sensor on epex_spot 4.x with full fee model + future-price chart' (#218) from afk/217 into main

dominik.polakovics referenced this pull request

2026-07-06 23:28:20 +02:00

fix(fw): EPEX spot price-forecast widget broken — chart doesn't render, shows a bare entry count #222