/// <summary>
/// Constructor
/// </summary>
/// <param name="logger">Logger</param>
/// <param name="options">Repository configuration options</param>
public EtcdConfigurationRepository(ILogger <EtcdConfigurationRepository <TModel, TKey> > logger, EtcdConfigurationRepositoryOptions options)
{
_logger = logger;
//Initialise serializer settings
_jsonSerializerSettings = new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.Auto,
//Use custom serializer to ensure 'id' and 'version' properties don't get written to etcd
ContractResolver = new ShouldSerializeContractResolver
{
NamingStrategy = new CamelCaseNamingStrategy()
},
NullValueHandling = NullValueHandling.Ignore,
Formatting = Formatting.None,
SerializationBinder = new DefaultSerializationBinder(),
};
//Create an initialisation task to create etcd client and initialise the watcher
_initTask = CreateClient(options)
.ContinueWith(async result =>
{
if (result.IsFaulted)
{
throw result.Exception;
}
await Initialise(result.Result);
_etcdClient = result.Result;
}).Unwrap();
//Setup ready task to complete when initialisation is complete and initial data is loaded
_readyTask = Task.WhenAll(_initTask, _dataLoaded.Task);
}
/// <summary>
/// Initialise etcd client
/// </summary>
/// <param name="options"></param>
private async Task <EtcdClient> CreateClient(EtcdConfigurationRepositoryOptions options)
{
EtcdClient etcdClient = null;
var lookup = new LookupClient();
if (options.UseEtcdClientDiscovery)
{
var dnsHostName = string.IsNullOrEmpty(options.DnsHostOverride)
? $"_etcd-client${(options.UseTLS ? "-ssl" : "")}.${options.EtcdClientDiscoveryDomain}"
: options.DnsHostOverride;
_logger.LogInformation("Attempting service discovery using hostname {dnsHostName}", dnsHostName);
var dnsResponse = await lookup.QueryAsync(dnsHostName, QueryType.SRV);
if (dnsResponse.Answers.Count > 0)
{
foreach (var srvRecord in dnsResponse.Answers.SrvRecords())
{
_logger.LogInformation($"Connecting to etcd host {srvRecord.Target} using port {options.PortOverride ?? srvRecord.Port}.");
var tmpEtcdClient = new EtcdClient(srvRecord.Target, options.PortOverride ?? srvRecord.Port, options.Username, options.Password);
try
{
await tmpEtcdClient.StatusASync(new Etcdserverpb.StatusRequest());
etcdClient = tmpEtcdClient;
break;
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Failed to connect to etcd cluster.");
tmpEtcdClient.Dispose();
}
}
}
if (etcdClient == null)
{
if (!options.UseTLS) //Try again with TLS
{
_logger.LogInformation("Retrying discovery etcd cluster using TLS.");
options.UseTLS = true;
etcdClient = await CreateClient(options);
}
else
{
throw new InvalidOperationException("Unable to connect to a etcd cluster because service discovery operations failed.");
}
}
}
else if (!string.IsNullOrEmpty(options.DnsHostOverride))
{
_logger.LogInformation($"Connecting to etcd host {options.DnsHostOverride} using port {options.PortOverride ?? 2379}.");
etcdClient = new EtcdClient(options.DnsHostOverride, options.PortOverride ?? 2379, options.Username, options.Password);
}
else
{
throw new ArgumentException("Must specify 'DnsHostOverride option' if 'UseEtcdDiscovery' option is set to false.");
}
return(etcdClient);
}
