Add new docker image

ci/docker/conda-python-docs.dockerfile

@@ -0,0 +1,26 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+ARG repo
+ARG arch=amd64
+ARG python=3.8
+ARG pandas=latest
+FROM ${repo}:${arch}-conda-python-${python}-pandas-${pandas}
+
+COPY ci/conda_env_sphinx.txt /arrow/ci/
+RUN mamba install -q -y --file arrow/ci/conda_env_sphinx.txt && \
+    mamba clean --all

ci/docker/conda-python-pandas.dockerfile

@@ -23,10 +23,8 @@ FROM ${repo}:${arch}-conda-python-${python}
 ARG pandas=latest
 ARG numpy=latest
 
-# the doc builds are using the conda-python-pandas image,
-# so ensure to install doc requirements
-COPY ci/conda_env_sphinx.txt /arrow/ci/
-RUN mamba install -q -y --file arrow/ci/conda_env_sphinx.txt && \
+COPY ci/conda_env_python.txt /arrow/ci/
+RUN mamba install -q -y --file arrow/ci/conda_env_python.txt && \
     mamba clean --all
 
 COPY ci/scripts/install_pandas.sh /arrow/ci/scripts/

docker-compose.yml

@@ -1200,7 +1200,17 @@ services:
     # Only a single rule is enabled for now to check undocumented arguments.
     # We should extend the list of enabled rules after adding this build to
     # the CI pipeline.
-    image: ${REPO}:${ARCH}-conda-python-${PYTHON}-pandas-${PANDAS}
+    image: ${REPO}:${ARCH}-conda-python-${PYTHON}-docs
+    build:
+      context: .
+      dockerfile: ci/docker/conda-python-docs.dockerfile
+      cache_from:
+            - ${REPO}:${ARCH}-conda-python-${PYTHON}-docs
+      args:
+            repo: ${REPO}
+            arch: ${ARCH}
+            python: ${PYTHON}
+            pandas: ${PANDAS}
     environment:
       <<: [*common, *ccache]
       ARROW_SUBSTRAIT: "ON"