# Author: Pengfei Ding (dingpf@fnal.gov)
# Created on 2017-06-20 
# For SAM4Users tutorial during FIFE workshiop in 2017
# This file is to be used during the hands-on session in the tutorial

#####################################################################
###  Slide 5
###  Setups 
#####################################################################

# On GPVM (e.g. dunegpvm01.fnal.gov)

# setup UPS etc.
source /cvmfs/dune.opensciencegrid.org/products/dune/setup_dune.sh

# Getting a valid Kerberos certificate and VOMS proxy
kx509
voms-proxy-init -noregen -rfc -voms dune:/dune/Role=Analysis

# Setup fife_utils, current version is v3_1_0
setup fife_utils

# set experiment name
export EXPERIMENT=dune

# setup ROOT (not needed by data management itself, but we will use
# ROOT in this tutorial to show how to use files interactively).
setup root v6_08_06d -f Linux64bit+2.6-2.12 -q e14:nu:prof

#####################################################################
###  Slide 6
###  Access file in dCache (I) - copy files to scratch
#####################################################################

# Create a directory in scratch area for this tutorial
export SCRATCH_DIR=/pnfs/dune/scratch/users/${USER}/tutorial
ifdh mkdir_p ${SCRATCH_DIR}


# Write files to scratch dCache (best to have files written in local
# disk or BlueArc first and then copy to the scratch area with ifdh
# or xrootd)

# create four 5MB dummy files, these files will be used for
# demonstration of data handling. You do not need to create the dummy
# files. You can use files of your own. 
for i in `seq 0 3`; do \
head -c 5242880 /dev/urandom > ~/dummy_${USER}_${i}.bin; \
done

# copy files into scratch dCache with “ifdh cp”.
ifdh cp -D ~/dummy_${USER}_[0-3].bin ${SCRATCH_DIR}
# To explore other options available with “ifdh cp”, just type “ifdh”.

#####################################################################
###  Slide 7 
###  Access file in dCache (II) - delete files in scratch
#####################################################################

# delete files with ”ifdh rm”
ifdh rm ${SCRATCH_DIR}/dummy_${USER}_0.bin
for i in `seq 1 3`; do \
ifdh rm ${SCRATCH_DIR}/dummy_${USER}_${i}.bin;\
done

# Copy files to scratch dCache using xrootd
xrdcp ~/dummy_${USER}_[0-3].bin ${SCRATCH_DIR} 
# or
xrdcp ~/dummy_${USER}_*.bin \
root://fndca1.fnal.gov:1094//pnfs/fnal.gov/usr/dune\
/scratch/users/${USER}/tutorial

# note that one should convert the path to scratch dCache to URI
# recognized by xrootd:
# e.g. from: /pnfs/dune/scratch/users/${USER}/dummy_${USER}_1.bin
#        to: root://fndca1.fnal.gov:1094//pnfs/fnal.gov/usr/dune\
#         /scratch/users/${USER}/dummy_${USER}_1.bin 

#####################################################################
###  Slide 8
###  Store files to persistent/tape-backed area (I)
###  - declare a SAM dataset with files in scratch area
#####################################################################

# choose a dataset name, better to be user, purpose and time specific
export TUTORIAL_DATASET=${USER}_tutorial_`date +%y%m%d%H%M`_01

# Add a SAM dataset for files in dCache scratch area
sam_add_dataset -n ${TUTORIAL_DATASET} -d ${SCRATCH_DIR}
# Instead of the “-d” option, it can take “-f” option followed by a
# text file containing a list of paths to files

# NOTE: sam_add_dataset will change the filename with UUID prefix.
ls ${SCRATCH_DIR}

# List files in the dataset
samweb list-definition-files ${TUTORIAL_DATASET} 

#####################################################################
###  Slide 9
###  Store files to persistent/tape-backed area (II)
###  - clone the dataset to persistent/tape-backed area
#####################################################################

# If the files under scratch area worth being kept for longer time,
# they can be added to SAM first with sam_add_dataset, followed by
# copying to the persistent or tape-backed area. 

# create a destination directory in the persistent area first
export PERSISTENT_DIR=/pnfs/dune/persistent/users/${USER}/tutorial
ifdh mkdir_p ${PERSISTENT_DIR}


# Copy the dataset to persistent area with sam_clone_dataset
sam_clone_dataset -n ${TUTORIAL_DATASET} -d ${PERSISTENT_DIR}

# Advanced tips for cloning large dataset:
# “sam_clone_dataset” has ”--njobs” option to launch multiple jobs to do
# the cloning. “launch_clone_jobs” can lauch grid jobs to do the cloning.

#####################################################################
###  Slide 10 
###  Store files to persistent/tape-backed area (III)
###  - remove replicas in the scratch area
#####################################################################

# check file locations, you will see two locations.
DUMMY_01=`samweb list-definition-files ${TUTORIAL_DATASET}|head -n 1`
samweb locate-file ${DUMMY_01}

# Remove replicas of the dataset files in the scratch area
sam_unclone_dataset -n ${TUTORIAL_DATASET} -d ${SCRATCH_DIR}

# List ${SCRATCH_DIR} to check if files are still there.
ls ${SCRATCH_DIR}

# check the file locations again, you will see only one location left
samweb locate-file ${DUMMY_01}

#####################################################################
###  Slide 11
###  Store files to persistent/tape-backed area (IV)
###  - validate dataset and deadling with missing files
#####################################################################

# Validate dataset, that is to check if each files in a dataset exists
# in the storage volume
sam_validate_dataset -n ${TUTORIAL_DATASET}

# Let’s move one file in the dataset and run “sam_validate_dataset”
FPATH=`samweb locate-file ${DUMMY_01}|cut -d ':' -f 2`
ifdh mv ${FPATH}/${DUMMY_01} \
${PERSISTENT_DIR}/
sam_validate_dataset -n ${TUTORIAL_DATASET}

# When there is a file missing, one can either replace the file with 
# a backup copy; or use “--prune” option to remove the file from the
# dataset; otherwise there will be errors when using SAM record for
# file access.
sam_validate_dataset -n ${TUTORIAL_DATASET} --prune

# Let’s list the files in the dataset again
samweb list-definition-files ${TUTORIAL_DATASET}

#####################################################################
###  Slide 12
###  Store files to persistent/tape-backed area (V)
###  - retire dataset
#####################################################################

# This will delete the dataset definition in SAM, retire all files
# contained in the dataset and delete them from disk, but if the files 
# are the last copy, they will not be deleted. “-j” (“--just_say” 
# option allow you to see what will be done without actually doing them.
sam_retire_dataset -n ${TUTORIAL_DATASET} -j

# You can use “--keep_files” option if you don’t want to delete the
# files.
sam_retire_dataset -n ${TUTORIAL_DATASET} --keep_files

# Once the dataset being retired, you can revert the file names for the
# last copy of files with sam_revert_names
sam_revert_names -d ${PERSISTENT_DIR}