public ILogsProcessor Build()
{
if (Processors == null || Processors.Count == 0)
{
throw new ArgumentNullException(nameof(Processors));
}
if (Eth == null)
{
throw new ArgumentNullException(nameof(Eth));
}
BigInteger?lastBlockProcessed = MinimumBlockNumber == null || MinimumBlockNumber == 0 ? null : MinimumBlockNumber - 1;
BlockProgressRepository = BlockProgressRepository ?? new InMemoryBlockchainProgressRepository(lastBlockProcessed);
var progressService = new BlockProgressService(Eth.Blocks, MinimumBlockNumber, BlockProgressRepository, MinimumBlockConfirmations);
var processor = new BlockRangeLogsProcessor(Eth.Filters.GetLogs, Processors, Filters?.ToArray(), Log);
var batchProcessorService = new LogsProcessor(processor, progressService, BlocksPerBatch, BatchProcessedCallback, FatalErrorCallback, Log);
batchProcessorService.OnDisposing += disposeHandler;
return(batchProcessorService);
void disposeHandler(object s, EventArgs src)
{
while (_disposalStack.Count > 0)
{
_disposalStack.Pop().Dispose();
}
batchProcessorService.OnDisposing -= disposeHandler;
}
}
public async Task When_Cancellation_Is_Requested_Does_Not_Call_Processor()
{
var web3Mock = new Web3Mock();
var catchAllProcessor = new Mock <ILogProcessor>();
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, new[] { catchAllProcessor.Object });
catchAllProcessor
.Setup(p => p.IsLogForEvent(It.IsAny <FilterLog>()))
.Returns(true);
var logs = new[] { new FilterLog() };
var cancellationToken = new CancellationTokenSource();
//fake cancellation being raised after logs are retrieved but before processing
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(It.IsAny <NewFilterInput>(), null))
.Callback <NewFilterInput, object>((f, o) => cancellationToken.Cancel())
.ReturnsAsync(logs);
await logProcessor.ProcessAsync(new BlockRange(0, 10), cancellationToken.Token);
catchAllProcessor
.Verify(p => p.IsLogForEvent(It.IsAny <FilterLog>()), Times.Never);
}
public async Task Dedupes_Logs_Matching_Multiple_Filters()
{
var web3Mock = new Web3Mock();
var catchAllProcessor = new Mock <ILogProcessor>();
var filter1 = new NewFilterInput();
var filter2 = new NewFilterInput();
var filters = new[] { filter1, filter2 };
var mockProcessors = new[] { catchAllProcessor };
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, mockProcessors.Select(p => p.Object), filters);
var log1 = new FilterLog()
{
TransactionHash = "x", LogIndex = new HexBigInteger(0)
};
var duplicateLog = new FilterLog()
{
TransactionHash = "x", LogIndex = new HexBigInteger(0)
};
var log2 = new FilterLog()
{
TransactionHash = "y", LogIndex = new HexBigInteger(0)
};
var logsFromFilter1 = new[] { log1, duplicateLog };
var logsFromFilter2 = new[] { log2, duplicateLog };
catchAllProcessor
.Setup(p => p.IsLogForEvent(It.IsAny <FilterLog>()))
.Returns(true);
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(filter1, null))
.ReturnsAsync(logsFromFilter1);
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(filter2, null))
.ReturnsAsync(logsFromFilter2);
var processedLogs = new List <FilterLog>();
catchAllProcessor.Setup(p => p.ProcessLogsAsync(It.IsAny <FilterLog[]>()))
.Callback <FilterLog[]>(l => processedLogs.AddRange(l))
.Returns(Task.CompletedTask);
await logProcessor.ProcessAsync(new BlockRange(0, 0));
Assert.Equal(2, processedLogs.Count);
Assert.Contains(log1, processedLogs);
Assert.Contains(log2, processedLogs);
Assert.DoesNotContain(duplicateLog, processedLogs);
}
public async Task UsingTheIndividualComponents()
{
TransferMetadata.CurrentChainUrl = BlockchainUrl;
var web3 =
new Web3.Web3(BlockchainUrl);
using (var azureSearchService = new AzureSearchService(AzureSearchServiceName, _azureSearchApiKey))
{
await azureSearchService.DeleteIndexAsync(AzureTransferIndexName);
try
{
using (var transferIndexer =
await azureSearchService.CreateEventIndexer <TransferEvent_ERC20>(AzureTransferIndexName))
{
using (var transferProcessor =
new EventIndexProcessor <TransferEvent_ERC20>(transferIndexer))
{
var logProcessor = new BlockRangeLogsProcessor(
web3.Eth.Filters.GetLogs,
new ILogProcessor[] { transferProcessor });
var progressRepository =
new JsonBlockProgressRepository(CreateJsonFileToHoldProgress());
var progressService = new StaticBlockRangeProgressService(
3146684, 3146694, progressRepository);
var batchProcessorService = new LogsProcessor(
logProcessor, progressService, maxNumberOfBlocksPerBatch: 2);
BlockRange?lastBlockRangeProcessed;
do
{
lastBlockRangeProcessed = await batchProcessorService.ProcessOnceAsync();
} while (lastBlockRangeProcessed != null);
Assert.Equal(19, transferIndexer.Indexed);
}
}
}
finally
{
await azureSearchService.DeleteIndexAsync(AzureTransferIndexName);
}
}
}
public async Task Allocates_Matching_Logs_To_Processors()
{
var web3Mock = new Web3Mock();
var log1Processor = new Mock <ILogProcessor>();
var log2Processor = new Mock <ILogProcessor>();
var catchAllProcessor = new Mock <ILogProcessor>();
var mockProcessors = new[] { log1Processor, log2Processor, catchAllProcessor };
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, mockProcessors.Select(p => p.Object));
var log1 = new FilterLog();
var log2 = new FilterLog();
var log3 = new FilterLog();
var logs = new[] { log1, log2, log3 };
log1Processor.Setup(p => p.IsLogForEvent(log1)).Returns(true);
log2Processor.Setup(p => p.IsLogForEvent(log2)).Returns(true);
catchAllProcessor
.Setup(p => p.IsLogForEvent(It.IsAny <FilterLog>()))
.Returns(true);
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(It.IsAny <NewFilterInput>(), null))
.ReturnsAsync(logs);
var processedLogs = new Dictionary <Mock <ILogProcessor>, List <FilterLog> >();
foreach (var processor in mockProcessors)
{
processedLogs.Add(processor, new List <FilterLog>());
processor.Setup(p => p.ProcessLogsAsync(It.IsAny <FilterLog[]>()))
.Callback <FilterLog[]>(l => processedLogs[processor].AddRange(l))
.Returns(Task.CompletedTask);
}
await logProcessor.ProcessAsync(new BlockRange(0, 0));
Assert.Single(processedLogs[log1Processor], log1);
Assert.Single(processedLogs[log2Processor], log2);
Assert.True(logs.SequenceEqual(processedLogs[catchAllProcessor]));
}
public async Task Catches_Too_Many_Records_RpcException_And_Throws_Specific_Too_Many_Records_Exception()
{
var tooManyRecordsRpcEx = RpcResponseExceptionExtensions.CreateFakeTooManyRecordsRpcException();
var web3Mock = new Web3Mock();
var catchAllProcessor = new Mock <ILogProcessor>();
var filter1 = new NewFilterInput();
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, new[] { catchAllProcessor.Object }, new[] { filter1 });
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(filter1, null))
.Throws(tooManyRecordsRpcEx);
var actualException = await Assert.ThrowsAsync <TooManyRecordsException>(async() => await logProcessor.ProcessAsync(new BlockRange(0, 0)));
Assert.Same(tooManyRecordsRpcEx, actualException.InnerException);
}
public async Task Checks_For_Cancellation_Before_Each_Processing_Batch()
{
var web3Mock = new Web3Mock();
var catchAllProcessor1 = new Mock <ILogProcessor>();
var catchAllProcessor2 = new Mock <ILogProcessor>();
catchAllProcessor1
.Setup(p => p.IsLogForEvent(It.IsAny <FilterLog>()))
.Returns(true);
catchAllProcessor2
.Setup(p => p.IsLogForEvent(It.IsAny <FilterLog>()))
.Returns(true);
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, new[] { catchAllProcessor1.Object, catchAllProcessor2.Object });
var logs = new[] { new FilterLog() };
var cancellationToken = new CancellationTokenSource();
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(It.IsAny <NewFilterInput>(), null))
.ReturnsAsync(logs);
//cancel after processor 1 finishes
catchAllProcessor1
.Setup(p => p.ProcessLogsAsync(It.IsAny <FilterLog[]>()))
.Callback <FilterLog[]>(l => cancellationToken.Cancel())
.Returns(Task.CompletedTask);
await logProcessor.ProcessAsync(new BlockRange(0, 10), cancellationToken.Token);
catchAllProcessor1
.Verify(p => p.ProcessLogsAsync(It.IsAny <FilterLog[]>()), Times.Once);
catchAllProcessor2
.Verify(p => p.ProcessLogsAsync(It.IsAny <FilterLog[]>()), Times.Never);
}
public async Task Passes_Correct_Block_Range_To_Proxy()
{
var web3Mock = new Web3Mock();
var logProcessor = new BlockRangeLogsProcessor(
web3Mock.Web3, Array.Empty <ILogProcessor>());
var logs = Array.Empty <FilterLog>();
NewFilterInput actualFilter = null;
web3Mock.GetLogsMock
.Setup(p => p.SendRequestAsync(It.IsAny <NewFilterInput>(), null))
.Callback <NewFilterInput, object>((f, o) => actualFilter = f)
.ReturnsAsync(logs);
await logProcessor.ProcessAsync(new BlockRange(0, 10));
Assert.NotNull(actualFilter);
Assert.Equal(0, actualFilter.FromBlock.BlockNumber.Value);
Assert.Equal(10, actualFilter.ToBlock.BlockNumber.Value);
}
public virtual async Task <BigInteger> ProcessAsync(BigInteger from, BigInteger?to = null, CancellationTokenSource ctx = null, Action <LogBatchProcessedArgs> logBatchProcessedCallback = null)
{
if (!LogProcessors.Any())
{
throw new InvalidOperationException("No events to capture - use AddEventAsync to add listeners for indexable events");
}
var logProcessor = new BlockRangeLogsProcessor(
Web3.Eth.Filters.GetLogs,
LogProcessors,
Filters);
IBlockProgressService progressService = CreateProgressService(from, to);
var batchProcessorService = new LogsProcessor(
logProcessor, progressService, maxNumberOfBlocksPerBatch: MaxBlocksPerBatch);
if (to != null)
{
return(await ProcessRange(ctx, logBatchProcessedCallback, batchProcessorService));
}
return(await batchProcessorService.ProcessContinuallyAsync(ctx?.Token ?? new CancellationToken(), logBatchProcessedCallback));
}
public async Task WriteAnyMakerEventToQueue()
{
var config = TestConfiguration.LoadConfig();
string azureStorageConnectionString = config["AzureStorageConnectionString"];
var configurationContext = MakerDAOEventProcessingConfig.Create(PARTITION, out IdGenerator idGenerator);
IEventProcessingConfigurationRepository configurationRepository = configurationContext.CreateMockRepository(idGenerator);
var web3 = new Web3.Web3(TestConfiguration.BlockchainUrls.Infura.Mainnet);
// queue components
var queueFactory = new AzureSubscriberQueueFactory(azureStorageConnectionString);
// load subscribers and event subscriptions
var eventSubscriptionFactory = new EventSubscriptionFactory(
web3, configurationRepository, queueFactory);
List <IEventSubscription> eventSubscriptions = await eventSubscriptionFactory.LoadAsync(PARTITION);
// progress repo (dictates which block ranges to process next)
// maintain separate progress per partition via a prefix
var storageCloudSetup = new CloudTableSetup(azureStorageConnectionString, prefix: $"Partition{PARTITION}");
var blockProgressRepo = storageCloudSetup.CreateBlockProgressRepository();
//this ensures we only query the chain for events relating to this contract
var makerAddressFilter = new NewFilterInput()
{
Address = new[] { MakerDAOEventProcessingConfig.MAKER_CONTRACT_ADDRESS }
};
// load service
var progressService = new BlockProgressService(web3, MIN_BLOCK_NUMBER, blockProgressRepo);
var logProcessor = new BlockRangeLogsProcessor(web3, eventSubscriptions, makerAddressFilter);
var batchProcessorService = new LogsProcessor(logProcessor, progressService, MAX_BLOCKS_PER_BATCH);
// execute
var blockRangesProcessed = new List <BlockRange?>();
try
{
for (var i = 0; i < 2; i++) // 2 batch iterations
{
var ctx = new System.Threading.CancellationTokenSource();
var rangeProcessed = await batchProcessorService.ProcessOnceAsync(ctx.Token);
blockRangesProcessed.Add(rangeProcessed);
// save event subscription state after each batch
await configurationRepository.EventSubscriptionStates.UpsertAsync(eventSubscriptions.Select(s => s.State));
}
}
finally
{
await ClearDown(configurationContext, storageCloudSetup, queueFactory);
}
var subscriptionState = await configurationRepository.EventSubscriptionStates.GetAsync(eventSubscriptions[0].Id);
Assert.Equal(2, (int)subscriptionState.Values["HandlerInvocations"]);
Assert.Equal(28, (int)subscriptionState.Values["EventsHandled"]);
}
public async Task WriteTransferEventsForMakerDAOToAzureStorage()
{
// Load config
// - this will contain the secrets and connection strings we don't want to hard code
var config = TestConfiguration.LoadConfig();
string azureStorageConnectionString = config["AzureStorageConnectionString"];
// Create a proxy for the blockchain
var web3 = new Web3.Web3(TestConfiguration.BlockchainUrls.Infura.Mainnet);
// Create an Azure Table Storage Factory
// - The factory communicates with Azure to create and get different tables
var tableStorageFactory = new AzureTablesSubscriberRepositoryFactory(azureStorageConnectionString);
// Create a Handler for a Table
// - It wraps a table repository
// - This is where we're going to put the matching event logs
// - we're supplying a table prefix
// - the actual table name would be "<prefix>TransactionLogs")
// - this allows us to have different tables for different types of event logs
// - the handler implements ILogHandler
// - ILogHandler is a really simple interface to implement if you wish to customise the storage
var storageHandlerForLogs = await tableStorageFactory.GetLogRepositoryHandlerAsync(tablePrefix : "makerdaotransfersstorage");
// Create an event subscription specifically for ERC20 Transfers
// - Passing in the maker dao address to ensure only logs with a matching address are processed
// - There is an option to pass an implementation of IEventHandlerHistoryRepository in to the constructor
// - This would record history for each event handler and is used to prevent duplication
var eventSubscription = new EventSubscription <TransferEventDto>(
contractAddressesToMatch: new[] { MAKER_CONTRACT_ADDRESS });
// Assign the storage handler to the event subscription
// - Matching events will be passed to the handler
// - internally the handler passes the events to the repository layer which writes them to Azure
eventSubscription.AddStorageHandler(storageHandlerForLogs);
// Azure storage setup
// - this example reads and writes block progress to an Azure storage table
// - to avoid collision with other samples we provide a prefix
var storageCloudSetup = new CloudTableSetup(azureStorageConnectionString, prefix: $"makerdaotransfersstorage");
// Create a progress repository
// - It stores and retrieves the most recent block processed
var blockProgressRepo = storageCloudSetup.CreateBlockProgressRepository();
// Create a progress service
// - This uses the progress repo to dictate what blocks to process next
// - The MIN_BLOCK_NUMBER dictates the starting point if the progress repo is empty or has fallen too far behind
var progressService = new BlockProgressService(web3, MIN_BLOCK_NUMBER, blockProgressRepo);
// Create a filter
// - This is essentially the query that is sent to the chain when retrieving logs
// - It is OPTIONAL - without it, all logs in the block range are requested
// - The filter is invoked before any event subscriptions evaluate the logs
// - The subscriptions are free to implement their own matching logic
// - In this sample we're only interested in MakerDAO logs
// - Therefore it makes sense to restrict the number of logs to retrieve from the chain
var makerAddressFilter = new NewFilterInput()
{
Address = new[] { MAKER_CONTRACT_ADDRESS }
};
// Create a log processor
// - This uses the blockchainProxy to get the logs
// - It sends each log to the event subscriptions to indicate if the logs matches the subscription criteria
// - It then allocates matching logs to separate batches per event subscription
var logProcessor = new BlockRangeLogsProcessor(web3, new[] { eventSubscription }, makerAddressFilter);
// Create a batch log processor service
// - It uses the progress service to calculates the block range to progress
// - It then invokes the log processor - passing in the range to process
// - It updates progress via the progress service
var batchProcessorService = new LogsProcessor(logProcessor, progressService, MAX_BLOCKS_PER_BATCH);
// execute
try
{
// Optional cancellation token
// - Useful for cancelling long running processing operations
var ctx = new System.Threading.CancellationTokenSource();
// instruct the service to get and process the next range of blocks
// when the rangeProcessed is null - it means there was nothing to process
var rangeProcessed = await batchProcessorService.ProcessOnceAsync(ctx.Token);
// ensure we have processed the expected number of events
// the event subscription has state which can record running totals across many processing batches
Assert.Equal(11, eventSubscription.State.GetInt("EventsHandled"));
// get the row count from azure storage
// the querying on storage is limited
// the TransactionHash is the partitionkey and the rowkey is the LogIndex
// this allows us to query by tx hash
var logRepositoryHandler = storageHandlerForLogs as TransactionLogRepositoryHandler;
var repository = logRepositoryHandler.TransactionLogRepository as TransactionLogRepository;
var expectedTransactionHashes = new[]
{
"0x8d58abc578f5e321f2e6b7c0637ccc60fbf62b39b120691cbf19ff201f5069b0",
"0x0bee561ac6bafb59bcc4c48fc4c1225aaedbab3e8089acea420140aafa47f3e5",
"0x6fc82b076fa7088581a80869cb9c7a08d7f8e897670a9f67e39139b39246da7e",
"0xdc2ee28db35ed5dbbc9e18a7d6bdbacb6e6633a9fce1ecda99ea7e1cf4bc8c72",
"0xcd2fea48c84468f70c9a44c4ffd7b26064a2add8b72937edf593634d2501c1f6",
"0x3acf887420887148222aab1d25d4d4893794e505ef276cc4cb6a48fffc6cb381",
"0x96129f905589b2a95c26276aa7e8708a12381ddec50485d6684c4abf9a5a1d00"
};
List <TransactionLog> logsFromRepo = new List <TransactionLog>();
foreach (var txHash in expectedTransactionHashes)
{
logsFromRepo.AddRange(await repository.GetManyAsync(txHash));
}
Assert.Equal(11, logsFromRepo.Count);
}
finally
{
// delete any data from Azure
await storageCloudSetup.GetCountersTable().DeleteIfExistsAsync();
await tableStorageFactory.DeleteTablesAsync();
}
}
public async Task WebJobExample()
{
var config = TestConfiguration.LoadConfig();
string azureStorageConnectionString = config["AzureStorageConnectionString"];
string azureSearchKey = config["AzureSearchApiKey"];
var configurationContext = EventProcessingConfigMock.Create(PARTITION, out IdGenerator idGenerator);
IEventProcessingConfigurationRepository configurationRepository = configurationContext.CreateMockRepository(idGenerator);
var web3 = new Web3.Web3(TestConfiguration.BlockchainUrls.Infura.Rinkeby);
// search components
var searchService = new AzureSearchService(serviceName: AZURE_SEARCH_SERVICE_NAME, searchApiKey: azureSearchKey);
var searchIndexFactory = new AzureSubscriberSearchIndexFactory(searchService);
// queue components
var queueFactory = new AzureSubscriberQueueFactory(azureStorageConnectionString);
// subscriber repository
var repositoryFactory = new AzureTablesSubscriberRepositoryFactory(azureStorageConnectionString);
// load subscribers and event subscriptions
var eventSubscriptionFactory = new EventSubscriptionFactory(
web3, configurationRepository, queueFactory, searchIndexFactory, repositoryFactory);
List <IEventSubscription> eventSubscriptions = await eventSubscriptionFactory.LoadAsync(PARTITION);
// progress repo (dictates which block ranges to process next)
// maintain separate progress per partition via a prefix
var storageCloudSetup = new CloudTableSetup(azureStorageConnectionString, prefix: $"Partition{PARTITION}");
var blockProgressRepo = storageCloudSetup.CreateBlockProgressRepository();
// load service
var progressService = new BlockProgressService(web3, MIN_BLOCK_NUMBER, blockProgressRepo);
var logProcessor = new BlockRangeLogsProcessor(web3, eventSubscriptions);
var batchProcessorService = new LogsProcessor(logProcessor, progressService, MAX_BLOCKS_PER_BATCH);
// execute
BlockRange?rangeProcessed;
try
{
var ctx = new System.Threading.CancellationTokenSource();
rangeProcessed = await batchProcessorService.ProcessOnceAsync(ctx.Token);
}
finally
{
await ClearDown(configurationContext, storageCloudSetup, searchService, queueFactory, repositoryFactory);
}
// save event subscription state
await configurationRepository.EventSubscriptionStates.UpsertAsync(eventSubscriptions.Select(s => s.State));
// assertions
Assert.NotNull(rangeProcessed);
Assert.Equal((ulong)10, rangeProcessed.Value.BlockCount);
var subscriptionState1 = configurationContext.GetEventSubscriptionState(eventSubscriptionId: 1); // interested in transfers with contract queries and aggregations
var subscriptionState2 = configurationContext.GetEventSubscriptionState(eventSubscriptionId: 2); // interested in transfers with simple aggregation
var subscriptionState3 = configurationContext.GetEventSubscriptionState(eventSubscriptionId: 3); // interested in any event for a specific address
Assert.Equal("4009000000002040652615", subscriptionState1.Values["RunningTotalForTransferValue"].ToString());
Assert.Equal((uint)19, subscriptionState2.Values["CurrentTransferCount"]);
var txForSpecificAddress = (List <string>)subscriptionState3.Values["AllTransactionHashes"];
Assert.Equal("0x362bcbc78a5cc6156e8d24d95bee6b8f53d7821083940434d2191feba477ae0e", txForSpecificAddress[0]);
Assert.Equal("0xe63e9422dedf84d0ce13f9f75ebfd86333ce917b2572925fbdd51b51caf89b77", txForSpecificAddress[1]);
var blockNumbersForSpecificAddress = (List <HexBigInteger>)subscriptionState3.Values["AllBlockNumbers"];
Assert.Equal((BigInteger)4063362, blockNumbersForSpecificAddress[0].Value);
Assert.Equal((BigInteger)4063362, blockNumbersForSpecificAddress[1].Value);
}
public async Task QueueAllEventsForMakerDAOContract()
{
// Load config
// - this will contain the secrets and connection strings we don't want to hard code
var config = TestConfiguration.LoadConfig();
string azureStorageConnectionString = config["AzureStorageConnectionString"];
// Create a proxy for the blockchain
var web3 = new Web3.Web3(TestConfiguration.BlockchainUrls.Infura.Mainnet);
// Create Queue Factory
// - In this sample we're targetting Azure
// - The factory communicates with Azure to create and get different queues
var queueFactory = new AzureSubscriberQueueFactory(azureStorageConnectionString);
// Create a Queue
// - This is where we're going to put the matching event logs
var queue = await queueFactory.GetOrCreateQueueAsync("makerdaoevents");
// Get the maker DAO contract abi
// - from this we're able to match and decode the events in the contract
var contractAbi = new ABIDeserialiser().DeserialiseContract(MAKER_DAO_ABI);
// Create an event subscription for these events
// - Passing in the maker dao address to ensure only logs with a matching address are processed
// - There is an option to pass an implementation of IEventHandlerHistoryRepository in to the constructor
// - This would record history for each event handler and is used to prevent duplication
var eventSubscription = new EventSubscription(contractAbi.Events, new[] { MAKER_CONTRACT_ADDRESS });
// Assign the queue to the event subscription
// - Matching events will be written to this queue
// - By default a generic message is written to the queue
// - The message contains the raw log (aka FilterLog), decoded event parameter values and event metadata
// - Therefore the message schema is consistent across all messages sent to any queues
// - However - should you require your own queue message schema the method below accepts a custom message mapper
// - Ultimately the message is converted to json
eventSubscription.AddQueueHandler(queue);
// Azure storage setup
// - this example reads and writes block progress to an Azure storage table
// - to avoid collision with other samples we provide a prefix
var storageCloudSetup = new CloudTableSetup(azureStorageConnectionString, prefix: $"makerdao");
// Create a progress repository
// - It stores and retrieves the most recent block processed
var blockProgressRepo = storageCloudSetup.CreateBlockProgressRepository();
// Create a progress service
// - This uses the progress repo to dictate what blocks to process next
// - The MIN_BLOCK_NUMBER dictates the starting point if the progress repo is empty or has fallen too far behind
var progressService = new BlockProgressService(web3, MIN_BLOCK_NUMBER, blockProgressRepo);
// Create a filter
// - This is essentially the query that is sent to the chain when retrieving logs
// - It is OPTIONAL - without it, all logs in the block range are requested
// - The filter is invoked before any event subscriptions evaluate the logs
// - The subscriptions are free to implement their own matching logic
// - In this sample we're only interested in MakerDAO logs
// - Therefore it makes sense to restrict the number of logs to retrieve from the chain
var makerAddressFilter = new NewFilterInput()
{
Address = new[] { MAKER_CONTRACT_ADDRESS }
};
// Create a log processor
// - This uses the blockchainProxy to get the logs
// - It sends each log to the event subscriptions to indicate if the logs matches the subscription criteria
// - It then allocates matching logs to separate batches per event subscription
var logProcessor = new BlockRangeLogsProcessor(web3, new[] { eventSubscription }, makerAddressFilter);
// Create a batch log processor service
// - It uses the progress service to calculates the block range to progress
// - It then invokes the log processor - passing in the range to process
// - It updates progress via the progress service
var batchProcessorService = new LogsProcessor(logProcessor, progressService, MAX_BLOCKS_PER_BATCH);
// execute
try
{
// Optional cancellation token
// - Useful for cancelling long running processing operations
var ctx = new System.Threading.CancellationTokenSource();
// instruct the service to get and process the next range of blocks
// when the rangeProcessed is null - it means there was nothing to process
var rangeProcessed = await batchProcessorService.ProcessOnceAsync(ctx.Token);
// ensure we have processed the expected number of events
// the event subscription has state which can record running totals across many processing batches
Assert.Equal(16, eventSubscription.State.GetInt("EventsHandled"));
// get the message count from the queue
Assert.Equal(16, await queue.GetApproxMessageCountAsync());
}
finally
{
// delete any data from Azure
await ClearDown(queue, storageCloudSetup, queueFactory);
}
}
public async Task WritingCustomMessagesToTheQueue()
{
// Load config
// - this will contain the secrets and connection strings we don't want to hard code
var config = TestConfiguration.LoadConfig();
string azureStorageConnectionString = config["AzureStorageConnectionString"];
// Create a proxy for the blockchain
var web3 = new Web3.Web3(TestConfiguration.BlockchainUrls.Infura.Mainnet);
// Create Queue Factory
// - In this sample we're targetting Azure
// - The factory communicates with Azure to create and get different queues
var queueFactory = new AzureSubscriberQueueFactory(azureStorageConnectionString);
// Create a Queue
// - This is where we're going to put the matching event logs
var queue = await queueFactory.GetOrCreateQueueAsync("makerdaotransferscustom");
// Create an event subscription specifically for ERC20 Transfers
// - Passing in the maker dao address to ensure only logs with a matching address are processed
// - There is an option to pass an implementation of IEventHandlerHistoryRepository in to the constructor
// - This would record history for each event handler and is used to prevent duplication
var eventSubscription = new EventSubscription <TransferEventDto>(
contractAddressesToMatch: new[] { MAKER_CONTRACT_ADDRESS });
// Create a mapper that will convert the DecodedEvent into a custom message we want on the queue
// In this sample we're using a subscription that is specific to an EventDTO (EventSubscription<TransferEventDto>)
// This ensures that the decodedEvent.DecodedEventDto property is populated during processing
// ( If the subscription is not tied to an EventDTO the decodedEvent.DecodedEventDto property would be null
// BUT we can still read the event arguments (aka parameters or topics) from the decodedEvent.Event property)
var queueMessageMapper = new QueueMessageMapper((decodedEvent) =>
{
return(new CustomQueueMessageForTransfers
{
BlockNumber = decodedEvent.Log.BlockNumber.Value.ToString(),
TransactionHash = decodedEvent.Log.TransactionHash,
LogIndex = decodedEvent.Log.LogIndex.Value.ToString(),
Transfer = decodedEvent.DecodedEventDto as TransferEventDto
});
});
// Assign the queue to the event subscription
// - Matching events will be written to this queue
// - Pass a custom mapper to create a suitable queue message
// - Ultimately the message is converted to json
eventSubscription.AddQueueHandler(queue, queueMessageMapper);
// Azure storage setup
// - this example reads and writes block progress to an Azure storage table
// - to avoid collision with other samples we provide a prefix
var storageCloudSetup = new CloudTableSetup(azureStorageConnectionString, prefix: $"makerdaotransferscustom");
// Create a progress repository
// - It stores and retrieves the most recent block processed
var blockProgressRepo = storageCloudSetup.CreateBlockProgressRepository();
// Create a progress service
// - This uses the progress repo to dictate what blocks to process next
// - The MIN_BLOCK_NUMBER dictates the starting point if the progress repo is empty or has fallen too far behind
var progressService = new BlockProgressService(web3, MIN_BLOCK_NUMBER, blockProgressRepo);
// Create a filter
// - This is essentially the query that is sent to the chain when retrieving logs
// - It is OPTIONAL - without it, all logs in the block range are requested
// - The filter is invoked before any event subscriptions evaluate the logs
// - The subscriptions are free to implement their own matching logic
// - In this sample we're only interested in MakerDAO logs
// - Therefore it makes sense to restrict the number of logs to retrieve from the chain
var makerAddressFilter = new NewFilterInput()
{
Address = new[] { MAKER_CONTRACT_ADDRESS }
};
// Create a log processor
// - This uses the blockchainProxy to get the logs
// - It sends each log to the event subscriptions to indicate if the logs matches the subscription criteria
// - It then allocates matching logs to separate batches per event subscription
var logProcessor = new BlockRangeLogsProcessor(web3, new[] { eventSubscription }, makerAddressFilter);
// Create a batch log processor service
// - It uses the progress service to calculates the block range to progress
// - It then invokes the log processor - passing in the range to process
// - It updates progress via the progress service
var batchProcessorService = new LogsProcessor(logProcessor, progressService, MAX_BLOCKS_PER_BATCH);
// execute
try
{
// Optional cancellation token
// - Useful for cancelling long running processing operations
var ctx = new System.Threading.CancellationTokenSource();
// instruct the service to get and process the next range of blocks
// when the rangeProcessed is null - it means there was nothing to process
var rangeProcessed = await batchProcessorService.ProcessOnceAsync(ctx.Token);
// ensure we have processed the expected number of events
// the event subscription has state which can record running totals across many processing batches
Assert.Equal(11, eventSubscription.State.GetInt("EventsHandled"));
// get the message count from the queue
Assert.Equal(11, await queue.GetApproxMessageCountAsync());
//A sample message body from the queue
/*
* {"BlockNumber":"7540010","TransactionHash":"0x8d58abc578f5e321f2e6b7c0637ccc60fbf62b39b120691cbf19ff201f5069b0","LogIndex":"132","Transfer":{"From":"0x296c61eaf5bea208bbabc65ae01c3bc5270fe386","To":"0x2a8f1a6af55b705b7daee0776d6f97302de2a839","Value":119928660890733235}}
*/
}
finally
{
// delete any data from Azure
await ClearDown(queue, storageCloudSetup, queueFactory);
}
}
