internal static DurableCircuitBreaker ConfigureCircuitBreaker(IDurableEntityContext context, ILogger log)
{
string circuitBreakerId = context.EntityKey;
log?.LogCircuitBreakerMessage(circuitBreakerId, $"Setting configuration for circuit-breaker {circuitBreakerId}.");
// Intentionally no defaults - users should consciously decide what tolerances suit the operations invoked through the circuit-breaker.
TimeSpan breakDuration = XmlConvert.ToTimeSpan(GetCircuitConfiguration(circuitBreakerId, "BreakDuration"));
int maxConsecutiveFailures = Convert.ToInt32(GetCircuitConfiguration(circuitBreakerId, "MaxConsecutiveFailures"));
var breaker = new DurableCircuitBreaker(null)
{
CircuitState = CircuitState.Closed,
BrokenUntil = DateTime.MinValue,
ConsecutiveFailureCount = 0,
MaxConsecutiveFailures = maxConsecutiveFailures,
BreakDuration = breakDuration
};
if (breaker.BreakDuration <= TimeSpan.Zero)
{
throw new InvalidOperationException($"Circuit-breaker {circuitBreakerId} must be configured with a positive break-duration.");
}
if (breaker.MaxConsecutiveFailures <= 0)
{
throw new InvalidOperationException($"Circuit-breaker {circuitBreakerId} must be configured with a max number of consecutive failures greater than or equal to 1.");
}
return(breaker);
}
public async Task <DurableCircuitBreaker> GetBreakerState(string circuitBreakerId, ILogger log, IDurableClient durableClient)
{
log?.LogCircuitBreakerMessage(circuitBreakerId, $"Getting breaker state for circuit-breaker = '{circuitBreakerId}'.");
var readState = await durableClient.ReadEntityStateAsync <DurableCircuitBreaker>(DurableCircuitBreaker.GetEntityId(circuitBreakerId));
// We present a not-yet-initialized circuit-breaker as null (it will be initialized when successes or failures are first posted against it).
if (!readState.EntityExists || readState.EntityState == null)
{
return(null);
}
return(readState.EntityState);
}
public async Task <CircuitState> GetCircuitState(string circuitBreakerId, ILogger log, IDurableClient durableClient)
{
log?.LogCircuitBreakerMessage(circuitBreakerId, $"Getting circuit state for circuit-breaker = '{circuitBreakerId}'.");
var readState = await durableClient.ReadEntityStateAsync <DurableCircuitBreaker>(DurableCircuitBreaker.GetEntityId(circuitBreakerId));
// To keep the return type simple, we present a not-yet-initialized circuit-breaker as closed (it will be closed when first used).
return(readState.EntityExists && readState.EntityState != null ? readState.EntityState.CircuitState : CircuitState.Closed);
}
