zzstoatzz.io / prefect-server
prefect server in zig
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prefect-server / docs / scratch / configuration-audit.md
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configuration audit#

comparison of magic values in zig implementation vs python prefect server settings.

status: most high-priority items addressed, remaining items are medium/low priority

http server#

setting zig value python default python env var notes
port 4200 4200 PREFECT_SERVER_API_PORT ✅ matches
host 127.0.0.1 127.0.0.1 PREFECT_SERVER_API_HOST ✅ matches
workers 1 1 --workers CLI flag ✅ matches
threads 4 n/a - zap/facil.io specific; python uses async
max_clients 1000 n/a - zap/facil.io specific; uvicorn unlimited
max_body_size 16MB n/a - uvicorn default is unlimited
keepalive_timeout n/a 5s PREFECT_SERVER_API_KEEPALIVE_TIMEOUT not implemented in zig

notes#

  • threads/workers: zap's model is different (threads per worker). 4 threads × 1 worker is reasonable for single-process mode
  • max_body_size: 16MB is reasonable; python has no limit which could be a DoS vector

api behavior#

setting zig value python default python env var notes
default_limit 200 200 PREFECT_SERVER_API_DEFAULT_LIMIT ✅ matches (all endpoints)

database#

setting zig value python default python env var notes
pool_size 5 5 PREFECT_SERVER_DATABASE_SQLALCHEMY_POOL_SIZE ✅ matches
max_overflow n/a 10 PREFECT_SERVER_DATABASE_SQLALCHEMY_MAX_OVERFLOW not applicable to pg.zig
pool_recycle n/a 3600s - not implemented
statement_timeout n/a 10s PREFECT_SERVER_DATABASE_TIMEOUT not implemented
connection_timeout n/a 5s PREFECT_SERVER_DATABASE_CONNECTION_TIMEOUT not implemented

events#

setting zig value python default python env var notes
max_event_size n/a 1.5MB PREFECT_SERVER_EVENTS_MAXIMUM_SIZE_BYTES not validated in zig
max_related_resources n/a 100 PREFECT_SERVER_EVENTS_MAXIMUM_RELATED_RESOURCES not validated
max_labels_per_resource n/a 500 PREFECT_SERVER_EVENTS_MAXIMUM_LABELS_PER_RESOURCE not validated
retention_period n/a 7 days PREFECT_SERVER_EVENTS_RETENTION_PERIOD not implemented
websocket_backfill_page_size 250 250 PREFECT_SERVER_EVENTS_WEBSOCKET_BACKFILL_PAGE_SIZE ✅ matches
max_websocket_backfill 15min 15min PREFECT_SERVER_EVENTS_MAXIMUM_WEBSOCKET_BACKFILL ✅ matches

logging#

setting zig value python default python env var notes
level WARNING WARNING PREFECT_SERVER_LOGGING_LEVEL ✅ matches

deployments#

setting zig value python default python env var notes
schedule_max_runs n/a 50 PREFECT_SERVER_DEPLOYMENT_SCHEDULE_MAX_SCHEDULED_RUNS scheduler not implemented yet

datetime handling#

aspect zig implementation python notes
format ISO 8601 (2025-01-21T12:34:56.123456Z) ISO 8601 ✅ matches
timezone UTC (Z suffix) UTC-aware ✅ matches
precision microseconds microseconds ✅ matches
storage TEXT column TIMESTAMP column sqlite/postgres both use TEXT for consistency
parsing supports multiple formats pydantic datetime handles SQLite/postgres/ISO formats

utilities (src/utilities/time.zig)#

  • timestamp() - generate current time as ISO 8601 string
  • nowMicros() - get current time as microseconds since epoch
  • parse() - parse ISO 8601 strings (handles T/space separator, optional micros, timezone)
  • lessOrEqual() - compare two timestamp strings
  • isPast() - check if timestamp is in the past

schema defaults#

  • SQLite: strftime('%Y-%m-%dT%H:%M:%fZ', 'now') - ISO 8601 with 3-digit millis
  • PostgreSQL: TO_CHAR(NOW() AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS.US"Z"') - ISO 8601 with 6-digit micros

remaining work#

medium priority (production safety)#

  • add database statement timeout
  • add event size validation
  • add keepalive timeout support

low priority (completeness)#

  • event retention cleanup service
  • deployment scheduler service