Class: ElasticGraph::GraphQL::QueryExecutor

Inherits:
Object
  • Object
show all
Defined in:
lib/elastic_graph/graphql/query_executor.rb

Overview

Responsible for executing queries.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(schema:, monotonic_clock:, logger:, slow_query_threshold_ms:, datastore_search_router:) ⇒ QueryExecutor

Returns a new instance of QueryExecutor.



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# File 'lib/elastic_graph/graphql/query_executor.rb', line 21

def initialize(schema:, monotonic_clock:, logger:, slow_query_threshold_ms:, datastore_search_router:)
  @schema = schema
  @monotonic_clock = monotonic_clock
  @logger = logger
  @slow_query_threshold_ms = slow_query_threshold_ms
  @datastore_search_router = datastore_search_router
end

Instance Attribute Details

#schema ⇒ Object (readonly)

Returns the value of attribute schema.



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# File 'lib/elastic_graph/graphql/query_executor.rb', line 19

def schema
  @schema
end

Instance Method Details

#execute(query_string, client: Client::ANONYMOUS, variables: {}, timeout_in_ms: nil, operation_name: nil, context: {}, start_time_in_ms: @monotonic_clock.now_in_ms) ⇒ Object

Executes the given ‘query_string` using the provided `variables`.

‘timeout_in_ms` can be provided to limit how long the query runs for. If the timeout is exceeded, `RequestExceededDeadlineError` will be raised. Note that `timeout_in_ms` does not provide an absolute guarantee that the query will take no longer than the provided value; it is only used to halt datastore queries. In process computation can make the total query time exceeded the specified timeout.

‘context` is merged into the context hash passed to the resolvers.



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# File 'lib/elastic_graph/graphql/query_executor.rb', line 38

def execute(
  query_string,
  client: Client::ANONYMOUS,
  variables: {},
  timeout_in_ms: nil,
  operation_name: nil,
  context: {},
  start_time_in_ms: @monotonic_clock.now_in_ms
)
  # Before executing the query, prune any null-valued variable fields. This means we
  # treat `foo: null` the same as if `foo` was unmentioned. With certain clients (e.g.
  # code-gen'd clients in a statically typed language), it is non-trivial to avoid
  # mentioning variable fields they aren't using. It makes it easier to evolve the
  # schema if we ignore null-valued fields rather than potentially returning an error
  # due to a null-valued field referencing an undefined schema element.
  variables = ElasticGraph::Support::HashUtil.recursively_prune_nils_from(variables)

  query_tracker = QueryDetailsTracker.empty

  query, result = build_and_execute_query(
    query_string: query_string,
    variables: variables,
    operation_name: operation_name,
    client: client,
    context: context.merge({
      monotonic_clock_deadline: timeout_in_ms&.+(start_time_in_ms),
      elastic_graph_schema: @schema,
      schema_element_names: @schema.element_names,
      elastic_graph_query_tracker: query_tracker,
      datastore_search_router: @datastore_search_router
    }.compact)
  )

  unless result.to_h.fetch("errors", []).empty?
    @logger.error "      Query \#{query.operation_name}[1] for client \#{client.description} resulted in errors[2].\n\n      [1] \#{full_description_of(query)}\n\n      [2] \#{::JSON.pretty_generate(result.to_h.fetch(\"errors\"))}\n    EOS\n  end\n\n  unless query_tracker.hidden_types.empty?\n    @logger.warn \"\#{query_tracker.hidden_types.size} GraphQL types were hidden from the schema due to their backing indices being inaccessible: \#{query_tracker.hidden_types.sort.join(\", \")}\"\n  end\n\n  duration = @monotonic_clock.now_in_ms - start_time_in_ms\n\n  # Note: I also wanted to log the sanitized query if `result` has `errors`, but `GraphQL::Query#sanitized_query`\n  # returns `nil` on an invalid query, and I don't want to risk leaking PII by logging the raw query string, so\n  # we don't log any form of the query in that case.\n  if duration > @slow_query_threshold_ms\n    @logger.warn \"Query \#{query.operation_name} for client \#{client.description} with shard routing values \" \\\n      \"\#{query_tracker.shard_routing_values.sort.inspect} and search index expressions \#{query_tracker.search_index_expressions.sort.inspect} took longer \" \\\n      \"(\#{duration} ms) than the configured slow query threshold (\#{@slow_query_threshold_ms} ms). \" \\\n      \"Sanitized query:\\n\\n\#{query.sanitized_query_string}\"\n  end\n\n  unless client == Client::ELASTICGRAPH_INTERNAL\n    @logger.info({\n      \"message_type\" => \"ElasticGraphQueryExecutorQueryDuration\",\n      \"client\" => client.name,\n      \"query_fingerprint\" => fingerprint_for(query),\n      \"query_name\" => query.operation_name,\n      \"duration_ms\" => duration,\n      # Here we log how long the datastore queries took according to what the datastore itself reported.\n      \"datastore_server_duration_ms\" => query_tracker.datastore_query_server_duration_ms,\n      # Here we log an estimate for how much overhead ElasticGraph added on top of how long the datastore took.\n      # This is based on the duration, excluding how long the datastore calls took from the client side\n      # (e.g. accounting for network latency, serialization time, etc)\n      \"elasticgraph_overhead_ms\" => duration - query_tracker.datastore_query_client_duration_ms,\n      # According to https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html#metric-filters-extract-json,\n      # > Value nodes can be strings or numbers...If a property selector points to an array or object, the metric filter won't match the log format.\n      # So, to allow flexibility to deal with cloud watch metric filters, we coerce these values to a string here.\n      \"unique_shard_routing_values\" => query_tracker.shard_routing_values.sort.join(\", \"),\n      # We also include the count of shard routing values, to make it easier to search logs\n      # for the case of no shard routing values.\n      \"unique_shard_routing_value_count\" => query_tracker.shard_routing_values.count,\n      \"unique_search_index_expressions\" => query_tracker.search_index_expressions.sort.join(\", \"),\n      # Indicates how many requests we sent to the datastore to satisfy the GraphQL query.\n      \"datastore_request_count\" => query_tracker.query_counts_per_datastore_request.size,\n      # Indicates how many individual datastore queries there were. One datastore request\n      # can contain many queries (since we use `msearch`), so these counts can be different.\n      \"datastore_query_count\" => query_tracker.query_counts_per_datastore_request.sum,\n      \"over_slow_threshold\" => (duration > @slow_query_threshold_ms).to_s,\n      \"slo_result\" => slo_result_for(query, duration)\n    })\n  end\n\n  result\nend\n"