Initial commit: btcdata — BTC data backend service

Split from btcprice monolith. Owns DB, migrations, Binance WebSocket,
Kraken OHLC pollers, and exposes a JSON API with SSE price stream.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/migrations/20260217000000-create-binance-price.down.sql

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+DROP TABLE binance_price;

resources/migrations/20260217000000-create-binance-price.up.sql

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+CREATE TABLE binance_price (
+  id          BIGSERIAL PRIMARY KEY,
+  price       NUMERIC(18,8) NOT NULL,
+  recorded_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);

resources/migrations/20260218000000-create-kraken-hour.down.sql

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+DROP TABLE kraken_hour;

resources/migrations/20260218000000-create-kraken-hour.up.sql

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+CREATE TABLE kraken_hour (
+  ts          BIGINT         NOT NULL PRIMARY KEY,
+  open        NUMERIC(18,8)  NOT NULL,
+  high        NUMERIC(18,8)  NOT NULL,
+  low         NUMERIC(18,8)  NOT NULL,
+  close       NUMERIC(18,8)  NOT NULL,
+  vwap        NUMERIC(18,8)  NOT NULL,
+  volume      NUMERIC(24,8)  NOT NULL,
+  trade_count INTEGER        NOT NULL,
+  created_at  TIMESTAMPTZ    NOT NULL DEFAULT NOW()
+);

resources/migrations/20260218100000-create-kraken-day.down.sql

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+DROP TABLE kraken_day;

resources/migrations/20260218100000-create-kraken-day.up.sql

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+CREATE TABLE kraken_day (
+  ts          BIGINT         NOT NULL PRIMARY KEY,
+  open        NUMERIC(18,8)  NOT NULL,
+  high        NUMERIC(18,8)  NOT NULL,
+  low         NUMERIC(18,8)  NOT NULL,
+  close       NUMERIC(18,8)  NOT NULL,
+  vwap        NUMERIC(18,8)  NOT NULL,
+  volume      NUMERIC(24,8)  NOT NULL,
+  trade_count INTEGER        NOT NULL,
+  created_at  TIMESTAMPTZ    NOT NULL DEFAULT NOW()
+);

resources/queries.sql

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+-- queries for btcdata
+
+-- :name insert-binance-price! :! :n
+-- :doc Insert a Binance BTC price
+INSERT INTO binance_price (price) VALUES (:price)
+
+-- :name get-latest-binance-price :? :1
+-- :doc Get the most recent Binance BTC price
+SELECT price, recorded_at FROM binance_price ORDER BY id DESC LIMIT 1
+
+-- :name upsert-kraken-hour! :! :n
+-- :doc Upsert a Kraken hourly OHLC candle
+INSERT INTO kraken_hour (ts, open, high, low, close, vwap, volume, trade_count)
+VALUES (:ts, :open, :high, :low, :close, :vwap, :volume, :trade-count)
+ON CONFLICT (ts) DO UPDATE
+SET open = EXCLUDED.open,
+    high = EXCLUDED.high,
+    low  = EXCLUDED.low,
+    close = EXCLUDED.close,
+    vwap  = EXCLUDED.vwap,
+    volume = EXCLUDED.volume,
+    trade_count = EXCLUDED.trade_count
+
+-- :name get-latest-kraken-hour :? :1
+-- :doc Get the most recent Kraken hourly candle by timestamp
+SELECT ts, open, high, low, close, vwap, volume, trade_count, created_at
+FROM kraken_hour ORDER BY ts DESC LIMIT 1
+
+-- :name upsert-kraken-day! :! :n
+-- :doc Upsert a Kraken daily OHLC candle
+INSERT INTO kraken_day (ts, open, high, low, close, vwap, volume, trade_count)
+VALUES (:ts, :open, :high, :low, :close, :vwap, :volume, :trade-count)
+ON CONFLICT (ts) DO UPDATE
+SET open = EXCLUDED.open,
+    high = EXCLUDED.high,
+    low  = EXCLUDED.low,
+    close = EXCLUDED.close,
+    vwap  = EXCLUDED.vwap,
+    volume = EXCLUDED.volume,
+    trade_count = EXCLUDED.trade_count
+
+-- :name get-latest-kraken-day :? :1
+-- :doc Get the most recent Kraken daily candle by timestamp
+SELECT ts FROM kraken_day ORDER BY ts DESC LIMIT 1

resources/system.edn

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+{:system/env #profile {:dev :dev :test :test :prod :prod}
+
+ :server/http
+ {:port    #long #or [#env BTCDATA_PORT 4100]
+  :host    #or [#env HTTP_HOST "0.0.0.0"]
+  :handler #ig/ref :handler/ring}
+
+ :handler/ring
+ {:router    #ig/ref :router/core
+  :api-path  "/api"
+  :cors-origin #or [#env CORS_ORIGIN "*"]
+  :site-defaults-config
+  {:params    {:keywordize true
+               :multipart  true
+               :nested     true}
+   :cookies   false
+   :session   false
+   :security  {:anti-forgery   false
+               :xss-protection {:enable? true :mode :block}
+               :frame-options  :sameorigin}
+   :responses {:not-modified-responses true
+               :absolute-redirects     true
+               :content-types          true
+               :default-charset        "utf-8"}}}
+
+ :router/routes
+ {:routes #ig/refset :reitit/routes}
+
+ :router/core
+ {:routes #ig/ref :router/routes
+  :env    #ig/ref :system/env}
+
+ :db.sql/connection
+ {:jdbc-url #env JDBC_URL}
+
+ :db.sql/query-fn
+ {:conn        #ig/ref :db.sql/connection
+  :options     {}
+  :filename    "queries.sql"}
+
+ :db.sql/migrations
+ {:store            :database
+  :db               {:datasource #ig/ref :db.sql/connection}
+  :migrate-on-init? true}
+
+ :reitit.routes/api
+ {:base-path "/api"
+  :query-fn  #ig/ref :db.sql/query-fn
+  :binance   #ig/ref :ws/binance}
+
+ :ws/binance
+ {:query-fn #ig/ref :db.sql/query-fn
+  :uri      "wss://stream.binance.com:9443/ws/btcusdt@trade"}
+
+ :kraken/ohlc
+ {:query-fn #ig/ref :db.sql/query-fn}
+
+ :kraken/ohlc-day
+ {:query-fn #ig/ref :db.sql/query-fn}}