[Docker example] Streamline trace viewer app/image

A few small changes that make the example docker image smaller and build a bit faster:

- Build the theia trace viewer app/appliance in "production" mode (vs development)
- Have yarn remove the installed "devDependencies" after the build ("yarn --production")
  - adapt docker-entrypoint.sh to start the app directly rather than through @theia/cli
- Remove redundant "theia build" triggered in "prepare" package.json scripts entry - it's
  also done in Dockerfile

Signed-off-by: Marc Dumais <marc.dumais@ericsson.com>

examples/docker/Dockerfile

@@ -14,11 +14,12 @@ RUN apt-get update && apt-get install -y \
 COPY example-package.json /app/tte/package.json
 WORKDIR /app/tte/
 RUN yarn && \
-    npx theia build --app-target=\"browser\" --mode development && \
+    npx theia build --app-target=\"browser\" --mode production && \
     yarn autoclean --init && \
     echo *.ts >> .yarnclean && \
     echo *.ts.map >> .yarnclean && \
     echo *.spec.* >> .yarnclean && \
+    yarn --production && \
     yarn cache clean && \
     du -hs /app/tte
 

examples/docker/docker-entrypoint.sh

@@ -1,2 +1,3 @@
 #!/usr/bin/env bash
-yarn start --hostname 0.0.0.0 --port 4000
+# @theia/cli not installed, so start the app directly
+node ./src-gen/backend/main.js --hostname 0.0.0.0 --port 4000

examples/docker/example-package.json

@@ -37,7 +37,6 @@
     "@theia/cli": "1.45.1"
   },
   "scripts": {
-    "prepare": "theia build",
     "start": "theia start",
     "watch": "theia build --watch"
   },