Add strings_udf package for python 3.9 (#11730)

This PR fixes an issue where the `strings_udf` conda package for python 3.9 is missing, due to the way `strings_udf` is plumbed through CI.

Authors:
  - https://github.com/brandon-b-miller

Approvers:
  - AJ Schmidt (https://github.com/ajschmidt8)

URL: #11730

ci/cpu/upload.sh

@@ -34,10 +34,17 @@ if [[ "$BUILD_LIBCUDF" == "1" && "$UPLOAD_LIBCUDF" == "1" ]]; then
   LIBCUDF_FILES=$(echo "$LIBCUDF_FILES" | sed 's/.*libcudf-example.*//') # skip libcudf-example pkg upload
   gpuci_retry anaconda -t ${MY_UPLOAD_KEY} upload -u ${CONDA_USERNAME:-rapidsai} ${LABEL_OPTION} --skip-existing --no-progress $LIBCUDF_FILES
 
-  # also build strings_udf on cpu machines
-  export STRINGS_UDF_FILE=$(conda build --croot "${CONDA_BLD_DIR}" conda/recipes/strings_udf --python=$PYTHON --output)
+  # since strings_udf compiles libcudf code, we require it be built in the same environment as libcudf
+  # however since libcudf is agnostic to the python version that is present, we must vary it explicitly
+  # here if we want packages for both python 3.8 and 3.9
+  export STRINGS_UDF_FILE=$(conda build --croot "${CONDA_BLD_DIR}" conda/recipes/strings_udf --python=3.8 --output)
   test -e ${STRINGS_UDF_FILE}
-  echo "Upload strings_udf: ${STRINGS_UDF_FILE}"
+  echo "Upload strings_udf (python 3.8): ${STRINGS_UDF_FILE}"
+  gpuci_retry anaconda -t ${MY_UPLOAD_KEY} upload -u ${CONDA_USERNAME:-rapidsai} ${LABEL_OPTION} --skip-existing ${STRINGS_UDF_FILE} --no-progress
+
+  export STRINGS_UDF_FILE=$(conda build --croot "${CONDA_BLD_DIR}" conda/recipes/strings_udf --python=3.9 --output)
+  test -e ${STRINGS_UDF_FILE}
+  echo "Upload strings_udf (python 3.9): ${STRINGS_UDF_FILE}"
   gpuci_retry anaconda -t ${MY_UPLOAD_KEY} upload -u ${CONDA_USERNAME:-rapidsai} ${LABEL_OPTION} --skip-existing ${STRINGS_UDF_FILE} --no-progress
 fi