remote sampling - rules caching and rules matching

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_aws_xray_sampling_client.py

@@ -11,7 +11,7 @@
 
 
 class _AwsXRaySamplingClient:
-    def __init__(self, endpoint=None, log_level=None):
+    def __init__(self, endpoint: str = None, log_level: str = None):
         # Override default log level
         if log_level is not None:
             _logger.setLevel(log_level)

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_fallback_sampler.py

@@ -0,0 +1,39 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+from typing import Optional, Sequence
+
+from opentelemetry.context import Context
+from opentelemetry.sdk.trace.sampling import ALWAYS_ON, Sampler, SamplingResult, TraceIdRatioBased
+from opentelemetry.trace import Link, SpanKind
+from opentelemetry.trace.span import TraceState
+from opentelemetry.util.types import Attributes
+
+
+class _FallbackSampler(Sampler):
+    def __init__(self):
+        # TODO: Add Reservoir sampler
+        # pylint: disable=unused-private-member
+        self.__fixed_rate_sampler = TraceIdRatioBased(0.05)
+
+    # pylint: disable=no-self-use
+    def should_sample(
+        self,
+        parent_context: Optional[Context],
+        trace_id: int,
+        name: str,
+        kind: SpanKind = None,
+        attributes: Attributes = None,
+        links: Sequence[Link] = None,
+        trace_state: TraceState = None,
+    ) -> SamplingResult:
+        # TODO: add reservoir + fixed rate sampling
+        return ALWAYS_ON.should_sample(
+            parent_context, trace_id, name, kind=kind, attributes=attributes, links=links, trace_state=trace_state
+        )
+
+    # pylint: disable=no-self-use
+    def get_description(self) -> str:
+        description = (
+            "FallbackSampler{fallback sampling with sampling config of 1 req/sec and 5% of additional requests}"
+        )
+        return description

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_matcher.py

@@ -0,0 +1,67 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+import re
+
+from opentelemetry.semconv.resource import CloudPlatformValues
+from opentelemetry.util.types import Attributes
+
+cloud_platform_mapping = {
+    CloudPlatformValues.AWS_LAMBDA.value: "AWS::Lambda::Function",
+    CloudPlatformValues.AWS_ELASTIC_BEANSTALK.value: "AWS::ElasticBeanstalk::Environment",
+    CloudPlatformValues.AWS_EC2.value: "AWS::EC2::Instance",
+    CloudPlatformValues.AWS_ECS.value: "AWS::ECS::Container",
+    CloudPlatformValues.AWS_EKS.value: "AWS::EKS::Container",
+}
+
+
+class _Matcher:
+    @staticmethod
+    def wild_card_match(text: str = None, pattern: str = None) -> bool:
+        if pattern == "*":
+            return True
+        if text is None or pattern is None:
+            return False
+        if len(pattern) == 0:
+            return len(text) == 0
+        for char in pattern:
+            if char in ("*", "?"):
+                return re.fullmatch(_Matcher.to_regex_pattern(pattern), text) is not None
+        return pattern == text
+
+    @staticmethod
+    def to_regex_pattern(rule_pattern: str) -> str:
+        token_start = -1
+        regex_pattern = ""
+        for index, char in enumerate(rule_pattern):
+            char = rule_pattern[index]
+            if char in ("*", "?"):
+                if token_start != -1:
+                    regex_pattern += re.escape(rule_pattern[token_start:index])
+                    token_start = -1
+                if char == "*":
+                    regex_pattern += ".*"
+                else:
+                    regex_pattern += "."
+            else:
+                if token_start == -1:
+                    token_start = index
+        if token_start != -1:
+            regex_pattern += re.escape(rule_pattern[token_start:])
+        return regex_pattern
+
+    @staticmethod
+    def attribute_match(attributes: Attributes = None, rule_attributes: dict = None) -> bool:
+        if rule_attributes is None or len(rule_attributes) == 0:
+            return True
+        if attributes is None or len(attributes) == 0 or len(rule_attributes) > len(attributes):
+            return False
+
+        matched_count = 0
+        for key, val in attributes.items():
+            text_to_match = val
+            pattern = rule_attributes.get(key, None)
+            if pattern is None:
+                continue
+            if _Matcher.wild_card_match(text_to_match, pattern):
+                matched_count += 1
+        return matched_count == len(rule_attributes)

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_rule.py

@@ -0,0 +1,91 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+from typing import Optional, Sequence
+
+from amazon.opentelemetry.distro.sampler._matcher import _Matcher, cloud_platform_mapping
+from amazon.opentelemetry.distro.sampler._sampling_rule import _SamplingRule
+from opentelemetry.context import Context
+from opentelemetry.sdk.resources import Resource
+from opentelemetry.sdk.trace.sampling import ALWAYS_ON, SamplingResult
+from opentelemetry.semconv.resource import ResourceAttributes
+from opentelemetry.semconv.trace import SpanAttributes
+from opentelemetry.trace import Link, SpanKind
+from opentelemetry.trace.span import TraceState
+from opentelemetry.util.types import Attributes
+
+
+class _Rule:
+    def __init__(self, sampling_rule: _SamplingRule):
+        self.sampling_rule = sampling_rule
+        # TODO add self.next_target_fetch_time from maybe time.process_time() or cache's datetime object
+        # TODO add statistics
+        # TODO change to rate limiter given rate, add fixed rate sampler
+        self.reservoir_sampler = ALWAYS_ON
+        # self.fixed_rate_sampler = None
+        # TODO add clientId
+
+    def should_sample(
+        self,
+        parent_context: Optional[Context],
+        trace_id: int,
+        name: str,
+        kind: SpanKind = None,
+        attributes: Attributes = None,
+        links: Sequence[Link] = None,
+        trace_state: TraceState = None,
+    ) -> SamplingResult:
+        return self.reservoir_sampler.should_sample(
+            parent_context, trace_id, name, kind=kind, attributes=attributes, links=links, trace_state=trace_state
+        )
+
+    def matches(self, resource: Resource, attributes: Attributes) -> bool:
+        http_target = None
+        http_url = None
+        http_method = None
+        http_host = None
+        service_name = None
+
+        if attributes is not None:
+            http_target = attributes.get(SpanAttributes.HTTP_TARGET, None)
+            http_method = attributes.get(SpanAttributes.HTTP_METHOD, None)
+            http_url = attributes.get(SpanAttributes.HTTP_URL, None)
+            http_host = attributes.get(SpanAttributes.HTTP_HOST, None)
+        # NOTE: The above span attribute keys are deprecated in favor of:
+        # URL_PATH/URL_QUERY, HTTP_REQUEST_METHOD, URL_FULL, SERVER_ADDRESS/SERVER_PORT
+        # For now, the old attribute keys are kept for consistency with other centralized samplers
+
+        # Resource shouldn't be none as it should default to empty resource
+        if resource is not None:
+            service_name = resource.attributes.get(ResourceAttributes.SERVICE_NAME, "")
+
+        # target may be in url
+        if http_target is None and http_url is not None:
+            scheme_end_index = http_url.find("://")
+            # Per spec, http.url is always populated with scheme://host/target. If scheme doesn't
+            # match, assume it's bad instrumentation and ignore.
+            if scheme_end_index > -1:
+                path_index = http_url.find("/", scheme_end_index + len("://"))
+                if path_index == -1:
+                    http_target = "/"
+                else:
+                    http_target = http_url[path_index:]
+
+        return (
+            _Matcher.attribute_match(attributes, self.sampling_rule.Attributes)
+            and _Matcher.wild_card_match(http_target, self.sampling_rule.URLPath)
+            and _Matcher.wild_card_match(http_method, self.sampling_rule.HTTPMethod)
+            and _Matcher.wild_card_match(http_host, self.sampling_rule.Host)
+            and _Matcher.wild_card_match(service_name, self.sampling_rule.ServiceName)
+            and _Matcher.wild_card_match(self.get_service_type(resource), self.sampling_rule.ServiceType)
+        )
+
+    # pylint: disable=no-self-use
+    def get_service_type(self, resource: Resource) -> str:
+        if resource is None:
+            return ""
+
+        cloud_platform = resource.attributes.get(ResourceAttributes.CLOUD_PLATFORM, None)
+        if cloud_platform is None:
+            return ""
+
+        return cloud_platform_mapping.get(cloud_platform, "")

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_rule_cache.py

@@ -0,0 +1,94 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+import copy
+import datetime
+from logging import getLogger
+from threading import Lock
+from typing import Optional, Sequence
+
+from amazon.opentelemetry.distro.sampler._fallback_sampler import _FallbackSampler
+from amazon.opentelemetry.distro.sampler._rule import _Rule
+from amazon.opentelemetry.distro.sampler._sampling_rule import _SamplingRule
+from opentelemetry.context import Context
+from opentelemetry.sdk.resources import Resource
+from opentelemetry.sdk.trace.sampling import SamplingResult
+from opentelemetry.trace import Link, SpanKind
+from opentelemetry.trace.span import TraceState
+from opentelemetry.util.types import Attributes
+
+_logger = getLogger(__name__)
+
+CACHE_TTL_SECONDS = 3600
+
+
+class _RuleCache:
+    rules: [_Rule] = []
+
+    def __init__(self, resource: Resource, fallback_sampler: _FallbackSampler, date_time: datetime, lock: Lock):
+        self.__cache_lock = lock
+        self.__resource = resource
+        self._fallback_sampler = fallback_sampler
+        self._date_time = date_time
+        self._last_modified = self._date_time.datetime.now()
+
+    def should_sample(
+        self,
+        parent_context: Optional[Context],
+        trace_id: int,
+        name: str,
+        kind: SpanKind = None,
+        attributes: Attributes = None,
+        links: Sequence[Link] = None,
+        trace_state: TraceState = None,
+    ) -> SamplingResult:
+        for rule in self.rules:
+            if rule.matches(self.__resource, attributes):
+                return rule.should_sample(
+                    parent_context,
+                    trace_id,
+                    name,
+                    kind=kind,
+                    attributes=attributes,
+                    links=links,
+                    trace_state=trace_state,
+                )
+
+        return self._fallback_sampler.should_sample(
+            parent_context, trace_id, name, kind=kind, attributes=attributes, links=links, trace_state=trace_state
+        )
+
+    def update_sampling_rules(self, new_sampling_rules: [_SamplingRule]) -> None:
+        new_sampling_rules.sort()
+        temp_rules = []
+        for sampling_rule in new_sampling_rules:
+            if sampling_rule.RuleName == "":
+                _logger.info("sampling rule without rule name is not supported")
+                continue
+            if sampling_rule.Version != 1:
+                _logger.info("sampling rule without Version 1 is not supported: RuleName: %s", sampling_rule.RuleName)
+                continue
+            temp_rules.append(_Rule(copy.deepcopy(sampling_rule)))
+
+        self.__cache_lock.acquire()
+
+        # map list of rules by each rule's sampling_rule name
+        rule_map = {rule.sampling_rule.RuleName: rule for rule in self.rules}
+
+        # If a sampling rule has not changed, keep its respective rule in the cache.
+        for index, new_rule in enumerate(temp_rules):
+            rule_name_to_check = new_rule.sampling_rule.RuleName
+            if rule_name_to_check in rule_map:
+                previous_rule = rule_map[rule_name_to_check]
+                if new_rule.sampling_rule == previous_rule.sampling_rule:
+                    temp_rules[index] = previous_rule
+        self.rules = temp_rules
+        self._last_modified = datetime.datetime.now()
+
+        self.__cache_lock.release()
+
+    def expired(self) -> bool:
+        self.__cache_lock.acquire()
+        try:
+            return datetime.datetime.now() > self._last_modified + datetime.timedelta(seconds=CACHE_TTL_SECONDS)
+        finally:
+            self.__cache_lock.release()

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/sampler/_sampling_rule.py

@@ -35,3 +35,29 @@ def __init__(
         self.ServiceType = ServiceType if ServiceType is not None else ""
         self.URLPath = URLPath if URLPath is not None else ""
         self.Version = Version if Version is not None else 0
+
+    def __lt__(self, other) -> bool:
+        if self.Priority == other.Priority:
+            # String order priority example:
+            # "A","Abc","a","ab","abc","abcdef"
+            return self.RuleName < other.RuleName
+        return self.Priority < other.Priority
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, _SamplingRule):
+            return False
+        return (
+            self.FixedRate == other.FixedRate
+            and self.HTTPMethod == other.HTTPMethod
+            and self.Host == other.Host
+            and self.Priority == other.Priority
+            and self.ReservoirSize == other.ReservoirSize
+            and self.ResourceARN == other.ResourceARN
+            and self.RuleARN == other.RuleARN
+            and self.RuleName == other.RuleName
+            and self.ServiceName == other.ServiceName
+            and self.ServiceType == other.ServiceType
+            and self.URLPath == other.URLPath
+            and self.Version == other.Version
+            and self.Attributes == other.Attributes
+        )