private async Task EnsureRulesUpToDate(SimpleSubscriptionDescription subscription, ManagementClient client, CancellationToken cancellationToken)
{
var newRules = BuildRules(subscription)
.ToArray();
var existingRules = await client
.GetRulesAsync(settings.SafeEffectiveTopicName, subscription.SafeSubscriptionName(), cancellationToken : cancellationToken)
.ConfigureAwait(false);
foreach (var newRule in newRules)
{
if (existingRules.Any(existingRule => existingRule.Name == newRule.Name))
{
continue;
}
logger.LogInformation(
$"Rule {newRule.Name} doesn't exist on the subscription; creating the rule.");
try
{
await client
.CreateRuleAsync(settings.SafeEffectiveTopicName, subscription.SafeSubscriptionName(), newRule, cancellationToken)
.ConfigureAwait(false);
}
catch (MessagingEntityAlreadyExistsException)
{
logger.LogWarning(
$"Rule {newRule.Name} has been created by another process that is competing with this process.");
}
}
foreach (var existingRule in existingRules)
{
if (newRules.Any(newRule => newRule.Name == existingRule.Name))
{
continue;
}
logger.LogInformation(
$"Rule {existingRule.Name} is no longer neeed; deleting the rule.");
try
{
await client
.DeleteRuleAsync(settings.SafeEffectiveTopicName, subscription.SafeSubscriptionName(), existingRule.Name, cancellationToken)
.ConfigureAwait(false);
}
catch (MessagingEntityNotFoundException)
{
logger.LogWarning(
$"Rule {existingRule.Name} has already been removed by another process that is competing with this process.");
}
}
}
public async Task EnsureInitialised(SimpleSubscriptionDescription subscription, string connectionString, CancellationToken cancellationToken)
{
var client = new ManagementClient(connectionString);
await EnsureTopicExists(client, cancellationToken)
.ConfigureAwait(false);
await EnsureSubscriptionExists(subscription, client, cancellationToken)
.ConfigureAwait(false);
await EnsureRulesUpToDate(subscription, client, cancellationToken)
.ConfigureAwait(false);
}
private static IEnumerable <RuleDescription> BuildRules(SimpleSubscriptionDescription subscription)
{
var index = 0;
var hashCode = subscription.GetHashCode();
var domainUnderTestClause = BuildDomainUnderTestRuleClause(subscription.SafeSubscriptionName());
yield return(new RuleDescription(
hashCode + "_" + (index++),
new SqlFilter(
$"{domainUnderTestClause} AND EXISTS({TransportHeaders.SpecificEndpoint}) AND {TransportHeaders.SpecificEndpoint} = '{subscription.SafeSubscriptionName()}'")));
var ruleStart = $"{domainUnderTestClause} AND NOT EXISTS({TransportHeaders.SpecificEndpoint}) AND (";
var sql = new StringBuilder();
var requireDelimiter = false;
sql.Append(ruleStart);
foreach (var messageType in subscription.MessageTypeNames)
{
if (sql.Length + messageType.Length + ruleStart.Length + 40 > RuleSqlExpressionMaximumLength)
{
yield return(BuildRuleAndResetBuilder(sql, hashCode, index, ruleStart));
index++;
}
else if (requireDelimiter)
{
sql.Append(" OR ");
}
requireDelimiter = true;
// TODO Enforce that type name does not contain a semi-colon or single quote or square bracket or underscore
sql.Append("MessageTypeNames LIKE '%;")
.Append(messageType)
.Append(";%'");
}
sql.Append(")");
yield return(new RuleDescription(
hashCode + "_" + (index++),
new SqlFilter(
sql.ToString())));
}
private async Task EnsureSubscriptionExists(SimpleSubscriptionDescription subscription, ManagementClient client, CancellationToken cancellationToken)
{
if (await client
.SubscriptionExistsAsync(
settings.SafeEffectiveTopicName,
subscription.SafeSubscriptionName())
.ConfigureAwait(false))
{
return;
}
logger.LogInformation(
$"Subscription {subscription.SafeSubscriptionName()} doesn't exist on the topic; creating the subscription.");
try
{
await client
.CreateSubscriptionAsync(
new AzureSubscriptionDescription(settings.SafeEffectiveTopicName, subscription.SafeSubscriptionName())
{
EnableBatchedOperations = true,
EnableDeadLetteringOnMessageExpiration = true,
LockDuration = TimeSpan.FromMinutes(1),
MaxDeliveryCount = 10,
RequiresSession = false
},
new RuleDescription("Default", new FalseFilter()),
cancellationToken)
.ConfigureAwait(false);
}
catch (MessagingEntityAlreadyExistsException)
{
logger.LogWarning(
$"Subscription {subscription.SafeSubscriptionName()} has been created by another process that is competing with this process.");
}
}
