Merge 972bf96 into 3291840

docker/Dockerfile

@@ -1,31 +1,47 @@
-FROM python:3.6-slim
+FROM python:3.6-slim as builder
 ARG DEBIAN_FRONTEND="noninteractive"
 WORKDIR /opt/pliers
 COPY . .
-RUN chmod a+rX -R .
-RUN apt-get update -qq \
-    && tmp_pkgs="cmake gcc g++ libc6-dev libgraphviz-dev libmagic-dev make" \
+# Install dependencies into a virtual environment so they can be easily copied into
+# the second stage.
+ENV PATH="/opt/venv/bin:$PATH"
+RUN chmod a+rX -R . \
+    && apt-get update -qq \
+    && apt-get install -yq --no-install-recommends \
+        cmake \
+        gcc \
+        g++ \
+        libc6-dev \
+        libgraphviz-dev \
+        libmagic-dev \
+        make \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+# Run this in different layers for faster rebuilds when debugging. The extra layers
+# do impose a size penalty, because we build the final image in a separate stage.
+RUN python -m venv /opt/venv
+RUN python -m pip install --no-cache-dir --requirement requirements.txt
+RUN python -m pip install --no-cache-dir --requirement optional-dependencies.txt
+RUN python -m pip install ipython notebook
+RUN python -m pip install --no-cache-dir --editable .
+RUN python -m spacy download en_core_web_sm
+
+FROM python:3.6-slim
+RUN useradd --no-user-group --create-home --shell /bin/bash pliers \
+    # Empty top level directories to facilitate use of the image in singularity
+    # on a box with kernel lacking overlay FS support
+    && mkdir -p /data /backup \
+    && apt-get update -qq \
     && apt-get install -yq --no-install-recommends \
         ffmpeg \
         graphviz \
         libmagic1 \
         tesseract-ocr \
-        $tmp_pkgs \
-    && pip install --no-cache-dir \
-        --requirement requirements.txt \
-        --requirement optional-dependencies.txt \
-        ipython \
-        notebook \
-    && pip install --no-cache-dir --editable . \
-    && python -m spacy download en_core_web_sm \
-    && rm -rf ~/.cache/pip \
-    && apt-get autoremove --purge -yq $tmp_pkgs \
     && apt-get clean \
-    && rm -rf /var/lib/apt/lists/* \
-    && useradd --no-user-group --create-home --shell /bin/bash pliers
-# Empty top level directories to facilitate use of the image in singularity
-# on a box with kernel lacking overlay FS support
-RUN mkdir -p /data /backup
+    && rm -rf /var/lib/apt/lists/*
+COPY --from=builder --chown=pliers /opt/venv /opt/venv
+COPY --from=builder --chown=pliers /opt/pliers /opt/pliers
+ENV PATH="/opt/venv/bin:$PATH"
 USER pliers
 RUN python -m pliers.support.download
-WORKDIR /work 
+WORKDIR /work