Configuration

The server is configured entirely through environment variables. Run it with:

python -m mef3io_server.server

Server

Variable	Default	Meaning
PORT	50051	gRPC server port.

Tile cache

Variable	Default	Meaning
TILE_DURATION_S	60	Tile length in seconds for timestamp-based access.
TILE_CACHE_MB	512	Global tile-cache budget in MB, shared across all open files.
CACHE_TTL_S	1800	Discard tiles not accessed within this many seconds; a finished session (e.g. a detector that moved on) is freed even before the byte budget is hit. 0 disables idle expiry.

Parallel decode

Cold reads and prefetch decode in worker processes, each holding its own mef3io session, so decode is genuinely parallel across channels.

Variable	Default	Meaning
USE_PROCESS_POOL	true	Decode cold reads / prefetch in worker processes. Set 0 for the in-process thread path.
READER_PROCESSES	auto (cpu_count - 1)	Total decode worker processes.
PREFETCH_PROCESSES	auto (half)	How many of those form the background prefetch lane; the rest (always ≥ 1) are the reserved foreground lane, so prefetch can never starve an interactive read.
MIN_PARALLEL_TILES	2	Minimum missing tiles before a cold read fans out to the pool; smaller reads stay in-process, where IPC is not worth it.

Prefetch / paging

Look-ahead and look-behind are measured in windows of the request's own size.

Variable	Default	Meaning
PREFETCH_AHEAD_WINDOWS	1	Windows to prefetch after the request (page forward).
PREFETCH_BEHIND_WINDOWS	1	Windows to prefetch before the request (page backward).
MAX_WORKERS	4	Thread-pool size for the in-process prefetch fallback used when USE_PROCESS_POOL=0.

Examples

# Interactive viewing — page both ways.
PORT=50052 PREFETCH_AHEAD_WINDOWS=1 PREFETCH_BEHIND_WINDOWS=1 \
  python -m mef3io_server.server

# Detector / automated single pass — stream forward, no look-behind, deeper look-ahead.
PREFETCH_AHEAD_WINDOWS=3 PREFETCH_BEHIND_WINDOWS=0 \
  python -m mef3io_server.server

Logging

Logs are written to both the console and a file (logs/server_YYYY-MM-DDTHH-MM-SS.log). The level is set in app_config.json (default: INFO):

{
  "log_level": "DEBUG"
}

Available levels: DEBUG, INFO, WARNING, ERROR, CRITICAL.