Revamp dockerfile for office-ui-fabric to reduce noise (#40147)

* Revamp dockerfile for office-ui-fabric to reduce noise and better handle recent changes to project structure

* Revert baseline change so it can be in the normal update, use node 12 since its LTS

Author: weswigham

tests/cases/docker/office-ui-fabric/Dockerfile

@@ -1,23 +1,20 @@
-FROM node:current
+# Lock to node 12 because the codebase throws hundreds of `Warning: Accessing non-existent property` warnings in node 14
+FROM node:12
 ENV CI=true
 ENV TF_BUILD=true
-RUN npm install -g yarn lerna --force
+# Download repo version, sets up better layer caching for the following clone
+ADD https://api.github.com/repos/OfficeDev/office-ui-fabric-react/git/ref/heads/master version.json
 RUN git clone https://github.com/OfficeDev/office-ui-fabric-react.git /office-ui-fabric-react
 WORKDIR /office-ui-fabric-react
 RUN git pull
+WORKDIR /
 COPY --from=typescript/typescript /typescript/typescript-*.tgz typescript.tgz
-# Sync up all TS versions used internally to the new one
-WORKDIR /office-ui-fabric-react/scripts
-RUN yarn add typescript@../typescript.tgz --exact --dev --ignore-scripts
-WORKDIR /office-ui-fabric-react/packages/tsx-editor
-RUN yarn add typescript@../../typescript.tgz --exact --ignore-scripts
-WORKDIR /office-ui-fabric-react/packages/migration
-RUN yarn add typescript@../../typescript.tgz --exact --ignore-scripts
-WORKDIR /office-ui-fabric-react/apps/vr-tests
-RUN yarn add typescript@../../typescript.tgz --exact --ignore-scripts
-WORKDIR /office-ui-fabric-react/apps/todo-app
-RUN yarn add typescript@../../typescript.tgz --exact --ignore-scripts
 WORKDIR /office-ui-fabric-react
-RUN yarn
-ENTRYPOINT [ "lerna" ]
-CMD [ "run", "build", "--stream", "--concurrency", "1", "--loglevel", "error", "--", "--production", "--lint", "--silent" ]
+# Sync up all TS versions used internally to the new one (we use `npm` because `yarn` chokes on tarballs installed
+# into multiple places in a workspace in a short timeframe (some kind of data race))
+RUN npx lerna exec --stream --concurrency 1 -- npm install /typescript.tgz --exact --ignore-scripts
+RUN npx yarn
+# Perform scss task to generate scss code if present
+RUN npx lerna exec --stream --concurrency 1 --bail=false -- yarn run just scss
+ENTRYPOINT [ "npx" ]
+CMD [ "lerna", "exec", "--stream", "--concurrency", "1", "--loglevel", "error", "--bail=false", "--", "yarn", "run", "just", "ts"]