add code for model downloading

Dockerfile

@@ -15,10 +15,23 @@ RUN npm ci
 COPY ./src/ ./src/
 RUN npm run build
 
+FROM node:18 AS model-fetch
+
+WORKDIR /app
+RUN wget https://github.com/jpreprocess/jpreprocess/releases/download/v0.6.1/naist-jdic-jpreprocess.tar.gz \
+    && tar xzf naist-jdic-jpreprocess.tar.gz \
+    && rm naist-jdic-jpreprocess.tar.gz
+RUN wget http://downloads.sourceforge.net/open-jtalk/hts_voice_nitech_jp_atr503_m001-1.05.tar.gz \
+    && tar xzf hts_voice_nitech_jp_atr503_m001-1.05.tar.gz \
+    && mv hts_voice_nitech_jp_atr503_m001-1.05/* ./ \
+    && rm hts_voice_nitech_jp_atr503_m001-1.05.tar.gz \
+    && rmdir hts_voice_nitech_jp_atr503_m001-1.05
+
 FROM gcr.io/distroless/nodejs18-debian12:nonroot AS runner
 WORKDIR /app
 ENV NODE_ENV=production
 COPY ./package.json ./
 COPY --from=builder /app/dist/ ./dist/
 COPY --from=deps /app/node_modules/ ./node_modules/
+COPY --from=model-fetch /app/ ./model/
 CMD ["dist/main.js"]

src/synthesis/index.ts

@@ -1,10 +1,7 @@
 import { Synthesizer } from "./synthesizer";
 import WorkerSynthesizer from "./worker-synthesizer";
 
-if (!process.env.DICTIONARY || !process.env.MODEL) {
-  throw new Error("Dictionary and model must be specified.");
-}
 export const synthesizer: Synthesizer = new WorkerSynthesizer(
-  process.env.DICTIONARY,
-  process.env.MODEL,
+  process.env.DICTIONARY ?? "/app/model/naist-jdic",
+  process.env.MODEL ?? "/app/model/nitech_jp_atr503_m001.htsvoice",
 );