private async Task <ValidationOutcome> ValidateAndScaleAsync(RuleContext context, IRedisInstance primary, IRedisInstance secondary)
{
// Last refresh time may be arbitrarily long, either because the rule hasn't been run for a long time, or
// because there was an autoscale that happened before. Hence, we need to refresh what we know.
await Task.WhenAll(primary.RefreshAsync(context.CancellationToken), secondary.RefreshAsync(context.CancellationToken)).ThrowIfFailureAsync();
// We are willing to scale iff:
// 1. The instance is ready to scale
// 2. The other instance is not being scaled, but may be not ready to scale
if (!primary.IsReadyToScale)
{
Emit(context, "Autoscale", Severity.Warning, $"Instance `{primary.Name}` is undergoing maintenance or autoscaling operation. State=[{primary.State}]");
if (primary.IsFailed)
{
return(ValidationOutcome.PrimaryFailed);
}
else
{
return(ValidationOutcome.PrimaryUndergoingAutoscale);
}
}
if (!secondary.IsReadyToScale && !secondary.IsFailed)
{
Emit(context, "Autoscale", Severity.Warning, $"Instance `{secondary.Name}` is undergoing maintenance or autoscaling operation. State=[{secondary.State}]");
return(ValidationOutcome.SecondaryUndergoingAutoscale);
}
await AttemptToScaleAsync(context, primary, context.CancellationToken);
return(ValidationOutcome.Success);
}
private async Task <ValidationOutcome> ValidateAndScaleAsync(RuleContext context, IRedisInstance primary, IRedisInstance secondary, bool allowFailedStateReporting)
{
// Last refresh time may be arbitrarily long, either because the rule hasn't been run for a long time, or
// because there was an autoscale that happened before. Hence, we need to refresh what we know.
await Task.WhenAll(primary.RefreshAsync(context.CancellationToken), secondary.RefreshAsync(context.CancellationToken)).ThrowIfFailureAsync();
if (allowFailedStateReporting)
{
if (!primary.IsReadyToScale)
{
Emit(context, "Autoscale", Severity.Warning, $"Instance `{primary.Name}` is undergoing maintenance or autoscaling operation. State=[{primary.State}]");
await CreateIcmForFailedStateIfNeededAsync(primary);
}
if (!secondary.IsReadyToScale)
{
Emit(context, "Autoscale", Severity.Warning, $"Instance `{secondary.Name}` is undergoing maintenance or autoscaling operation. State=[{secondary.State}]");
await CreateIcmForFailedStateIfNeededAsync(secondary);
}
}
// Both instances in a failed state means we need to open a Sev 2 against our own rotation to get them
// fixed as quickly as possible.
if (primary.IsFailed && secondary.IsFailed)
{
try
{
await EmitIcmAsync(
severity : _configuration.Environment.IsProduction()? 2 : 3,
title : $"Redis instances {_primaryRedisInstance.Name} and {_secondaryRedisInstance.Name} are in a failed state",
description : TwoFailedInstancesDescription,
machines : null,
correlationIds : null,
cacheTimeToLive : _configuration.IcmIncidentCacheTtl);
}
catch (Exception e)
{
_configuration.Logger.Error($"Failed to emit IcM for failed instances {primary.Name} and {secondary.Name}: {e}");
}
}
// We are willing to scale iff:
// 1. The instance is ready to scale
// 2. The other instance is not being scaled, but may be not ready to scale
if (!primary.IsReadyToScale)
{
if (primary.IsFailed)
{
return(ValidationOutcome.PrimaryFailed);
}
else
{
return(ValidationOutcome.PrimaryUndergoingAutoscale);
}
}
if (!secondary.IsReadyToScale && !secondary.IsFailed)
{
return(ValidationOutcome.SecondaryUndergoingAutoscale);
}
await AttemptToScaleAsync(context, primary);
return(ValidationOutcome.Success);
}