xai-org/x-algorithm · error · ConfigFailure

Regex cacheExpirationMillis must be greater than 0

Error message

Regex cacheExpirationMillis must be greater than 0

What it means

BotMaker validates that the regex cache expiration (cacheExpirationMillis) is positive. This value drives how long compiled regexes stay cached; zero or negative expiration is meaningless, so ConfigFailure is thrown when the RegexOptions are applied (the final check before regexOptions = config).

Source

Thrown at botmaker/src/scala/com/twitter/botmaker/runtime/config/RegexConfigs.scala:47

      throw ConfigFailure(
        s"Regex maximumPendingRequests must be greater than 0"
      )
    }

    if (config.timeoutMilis <= 0) {
      throw ConfigFailure(
        s"Regex timeoutMilis must be greater than 0"
      )
    }

    if (config.maximumCacheItems <= 0) {
      throw ConfigFailure(
        s"Regex maximumCacheItems must be greater than 0"
      )
    }

    if (config.cacheExpirationMillis <= 0) {
      throw ConfigFailure(
        s"Regex cacheExpirationMillis must be greater than 0"
      )
    }

    regexOptions = config
  }
}

View on GitHub (pinned to 24c60942c5)

Solutions

1. Set cacheExpirationMillis to a positive duration in milliseconds (e.g. 3600000)
2. Verify the value's source (hocon/env) is actually populated and in milliseconds
3. Re-run config validation in a test before deploying so failures surface at build time

Example fix

// before
regexOptions = config.copy(cacheExpirationMillis = 0)

// after
regexOptions = config.copy(cacheExpirationMillis = 3_600_000L)

assert opts.cacheExpirationMillis > 0, "cacheExpirationMillis must be positive milliseconds"

try:
    applyRegexOptions(opts)
except ConfigFailure as e:
    log.warning("regex config rejected: %s", e); raise

When it happens

Trigger: Registering RegexOptions with cacheExpirationMillis <= 0; usually the last validation to fire after timeoutMillis and maximumCacheItems have passed.

Common situations: Setting expiration to 0 thinking it disables expiration (it does not); units confusion (passing seconds where millis expected, or 0 from an unset knob); mutating a shared config case class after construction.

Understand the failure class

Background: Config validation failed: what "invalid value for {key}" and settings-rejection errors mean across 19 open-source libraries — this error's family across 19 libraries.

Related errors

• Regex maximumCacheItems must be greater than 0
• ScheduledEvent ${config.eventType} intervalMillis must be a
• Conflict config name:${nameSeq.mkString}
• Event type '$eventType' does not match $eventTypeRegex.
• Field name '$fieldName' does not match $fieldNameRegex.

AI-assisted analysis of xai-org/x-algorithm@24c60942c5 (2026-08-28). Data as JSON: /api/errors/e0be7f76633771cb. Report an issue: GitHub.