# Copyright 2026, SERTIT-ICube - France, https://sertit.unistra.fr/
# This file is part of sertit-utils project
# https://github.com/sertit/sertit-utils
#
# Licensed 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.
"""
SNAP tools
"""
import logging
import os
import subprocess
import psutil
from packaging.version import Version
from sertit import misc, perf, strings
from sertit.logs import SU_NAME
MAX_CORES = perf.MAX_CORES
SU_MAX_CORE = perf.SU_MAX_CORE
JAVA_OPTS_XMX = "JAVA_OPTS_XMX"
"""
Maximum memory to use, default is 95% of the total virtual memory.
You can update it with the environment variable :code:`JAVA_OPTS_XMX`.
"""
SU_SNAP_TILE_SIZE = "SERTIT_UTILS_SNAP_TILE_SIZE"
"""
SNAP tile size, 512 by default.
You can update it with the environment variable :code:`SERTIT_UTILS_SNAP_TILE_SIZE`.
"""
SU_SNAP_LOG_LEVEL = "SERTIT_UTILS_SNAP_LOG_LEVEL"
"""
SNAP log level, WARNING by default.
You can update it with the environment variable :code:`SERTIT_UTILS_SNAP_LOG_LEVEL`.
"""
LOGGER = logging.getLogger(SU_NAME)
[docs]
def bytes2snap(nof_bytes: int) -> str:
"""
Convert nof bytes into snap-compatible Java options.
Example:
>>> bytes2snap(32000)
'31K'
Args:
nof_bytes (int): Byte nb
Returns:
str: Human-readable in bits
"""
symbols = ("K", "M", "G", "T", "P", "E", "Z", "Y")
prefix = {}
for idx, sym in enumerate(symbols):
prefix[sym] = 1 << (idx + 1) * 10
for sym in reversed(symbols):
if nof_bytes >= prefix[sym]:
value = int(float(nof_bytes) / prefix[sym])
return f"{value}{sym}"
return f"{nof_bytes}B"
[docs]
def get_gpt_cli(
graph_path: str, other_args: list = None, display_snap_opt: bool = False
) -> list:
"""
Get GPT command line with system OK optimizations.
To see options, type this command line with --diag (but it won't run the graph)
See https://senbox.atlassian.net/wiki/spaces/SNAP/pages/15269950/SNAP+Configuration
Example:
>>> get_gpt_cli("graph_path", other_args=[], display_snap_opt=True)
SNAP Release version 8.0
SNAP home: C:/Program Files/snap/bin/..
SNAP debug: null
SNAP log level: WARNING
Java home: c:/program files/snap/jre/jre
Java version: 1.8.0_242
Processors: 16
Max memory: 53.3 GB
Cache size: 30.0 GB
Tile parallelism: 14
Tile size: 2048 x 2048 pixels
To configure your gpt memory usage:
Edit snap/bin/gpt.vmoptions
To configure your gpt cache size and parallelism:
Edit .snap/etc/snap.properties or gpt -c ${cachesize-in-GB}G -q ${parallelism}
['gpt', '"graph_path"', '-q', 14, '-J-Xms2G -J-Xmx60G', '-J-Dsnap.log.level=WARNING',
'-J-Dsnap.jai.defaultTileSize=2048', '-J-Dsnap.dataio.reader.tileWidth=2048',
'-J-Dsnap.dataio.reader.tileHeigh=2048', '-J-Dsnap.jai.prefetchTiles=true', '-c 30G']
Args:
graph_path (str): Graph path
other_args (list): Other args as a list such as :code:`['-Pfile="in_file.zip", '-Pout="out_file.dim"']`
display_snap_opt (bool): Display SNAP options via --diag
Returns:
list: GPT command line as a list
"""
# Overload with env variables
if other_args is None:
other_args = []
# Overload with env variables
max_cores = perf.get_max_cores()
tile_size = int(os.getenv(SU_SNAP_TILE_SIZE, 512))
snap_log_level = os.getenv(SU_SNAP_LOG_LEVEL, "WARNING")
max_mem = int(os.environ.get(JAVA_OPTS_XMX, 0.95 * psutil.virtual_memory().total))
gpt_cli = [
"gpt",
strings.to_cmd_string(graph_path),
"-q",
max_cores, # Maximum parallelism
f"-J-Xms2G -J-Xmx{bytes2snap(max_mem)}", # Initially/max allocated memory
f"-J-Dsnap.log.level={snap_log_level}",
f"-J-Dsnap.jai.defaultTileSize={tile_size}",
f"-J-Dsnap.dataio.reader.tileWidth={tile_size}",
f"-J-Dsnap.dataio.reader.tileHeight={tile_size}",
"-J-Dsnap.dataio.bigtiff.compression.type=LZW",
"-J-Dsnap.dataio.bigtiff.tiling.width=512",
"-J-Dsnap.dataio.bigtiff.tiling.height=512",
"-J-Dsnap.jai.prefetchTiles=true",
"-J-Dplugin.manager.check.interval=NEVER", # Don't check for updates
f"-c {bytes2snap(int(0.5 * max_mem))}", # Tile cache set to 50% of max memory (up to 75%)
# '-x',
*other_args,
] # Clears the internal tile cache after writing a complete row to the target file
# LOGs
LOGGER.debug(gpt_cli)
if display_snap_opt:
misc.run_cli(gpt_cli + ["--diag"])
return gpt_cli
[docs]
def get_snap_version() -> Version:
"""Get SNAP version with a call to GPT --diag"""
snap_version = None
try:
output = subprocess.run(["gpt", "--diag"], capture_output=True)
except FileNotFoundError as exc: # pragma: no cover
raise FileNotFoundError("'gpt' not found in your PATH") from exc
stdout = output.stdout.decode("utf-8")
if stdout is not None:
version_str = stdout.split("\n")
try:
version_str = [v for v in version_str if "version" in v][0]
except IndexError as ex: # pragma: no cover
LOGGER.debug(ex)
else:
snap_version = version_str.split(" ")[-1]
snap_version = Version(snap_version)
return snap_version
