add docs and script to fetch rucio dataset files

tutorials/data-lake/pull-dataset/README.md

@@ -1 +1,16 @@
-# Pull dataset from Rucio data lake
+# Interact with Rucio dataset files
+
+The following script assumes that all the files within a DID are present in a RSE (Rucio Storage Element), and that this RSE is accessible locally.
+ - DIDs are composed of a scope plus a dataset name in the `SCOPE:DataSet` format.
+ - If the files are not present in the RSE, replicate the dataset on the desired RSE before running the script.
+
+Run the following bash script
+
+```bash
+> ./rucio_dataset_files.sh <SCOPE:DataSet> <output_file> <output_symlink_dir>
+
+# Example
+> ./rucio_dataset_files.sh calorimeter:training_data_hdf5 calorimeter_files.txt calorimeter_symlink_dir
+> cat calorimeter_files.txt
+> ls -l calorimeter_symlink_dir
+```

tutorials/data-lake/pull-dataset/rucio_dataset_files.sh

@@ -0,0 +1,34 @@
+#/bin/bash
+#
+# G. Guerrieri & E. Garcia (CERN) - Jun 2024
+#
+# This script runs only on VEGA
+# 
+# Usage - on a terminal run
+# > ./rucio_dataset_files.sh <SCOPE:DataSet> <output_file> <output_symlink_dir>
+
+set -e
+
+ds=$1
+name=$2
+location=$3
+
+pw=`pwd -P`
+
+if [[ -f "${name}" ]]; then rm ${name}.txt; fi
+touch ${name}.txt
+
+if [ -d "${location}" ]; then echo -e "Directory exists. Exiting\n${pw}/${location}" ; exit 1 ; fi
+mkdir $location
+
+for file in `rucio list-file-replicas --rse VEGA-DCACHE $ds | awk '{ print $12 }' | sed 's|https://dcache.sling.si:2880|/dcache/sling.si|g'`
+do
+  if [[ $file == "|" ]]; then continue; fi
+  fileReduced=`basename $file`
+  echo linking $fileReduced "..."
+  link=$location/${ds/:/.}.$fileReduced
+  ln -s $file $link
+  echo ${pw}/$link >> ${name}.txt
+done
+
+chmod -R 777 $3