/// <summary>
/// Query the reliable collection with the given name from the reliable state manager using the given query parameters.
/// </summary>
/// <param name="stateManager">Reliable state manager for the replica.</param>
/// <param name="context">Stateful Service Context.</param>
/// <param name="collection">Name of the reliable collection.</param>
/// <param name="query">OData query parameters.</param>
/// <param name="cancellationToken">Cancellation token.</param>
/// <returns>The json serialized results of the query.</returns>
public static async Task <IEnumerable <JToken> > QueryAsync(this IReliableStateManager stateManager,
StatefulServiceContext context, string collection, IEnumerable <KeyValuePair <string, string> > query, CancellationToken cancellationToken)
{
// Get the list of partitions (excluding the executing partition).
var partitions = await StatefulServiceUtils.GetPartitionsAsync(context).ConfigureAwait(false);
// Query all service partitions concurrently.
var remoteQueries = partitions.Select(p => QueryPartitionAsync(p, context, collection, query, cancellationToken));
var localQuery = stateManager.QueryPartitionAsync(collection, query, context.PartitionId, cancellationToken);
var queries = remoteQueries.Concat(new[] { localQuery });
// Aggregate all query results into a single list.
var queryResults = await Task.WhenAll(queries).ConfigureAwait(false);
var results = queryResults.SelectMany(r => r);
// Run the aggregation query to get the final results (e.g. for top, orderby, project).
var reliableState = await stateManager.GetQueryableState(collection).ConfigureAwait(false);
var entityType = reliableState.GetEntityType();
var objects = results.Select(r => r.ToObject(entityType));
var queryResult = ApplyQuery(objects, entityType, query, aggregate: true);
results = queryResult.Select(q => JObject.FromObject(q));
// Return the filtered data as json.
return(results);
}
/// <summary>
/// This implementation should not leak into the core Queryable code. It is dependent on the specific protocol
/// used to communicate with the other partitions (HTTP over ReverseProxy), and should be hidden behind an interface.
/// </summary>
private static async Task <IEnumerable <JToken> > QueryPartitionAsync(Partition partition,
StatefulServiceContext context, string collection, IEnumerable <KeyValuePair <string, string> > query, CancellationToken cancellationToken)
{
string endpoint = await StatefulServiceUtils.GetPartitionEndpointAsync(context, partition).ConfigureAwait(false);
string content = await StatefulServiceUtils.QueryPartitionAsync(endpoint, partition.PartitionInformation.Id, collection, query).ConfigureAwait(false);
var result = JsonConvert.DeserializeObject <ODataResult>(content);
return(result.Value);
}
private async Task ForwardQueryCollectionAsync(HttpContext httpContext, StatefulServiceContext serviceContext, IReliableStateManager stateManager, string collection, Guid partitionId)
{
// Forward the request to the correct partition.
var queryParameters = httpContext.Request.Query.Select(q => new KeyValuePair <string, string>(q.Key, q.Value));
string endpoint = await StatefulServiceUtils.GetPartitionEndpointAsync(serviceContext, partitionId).ConfigureAwait(false);
string content = await StatefulServiceUtils.QueryPartitionAsync(endpoint, partitionId, collection, queryParameters);
httpContext.Response.ContentType = "application/json";
httpContext.Response.StatusCode = (int)HttpStatusCode.OK;
// Write the response.
await httpContext.Response.WriteAsync(content).ConfigureAwait(false);
}
