Add exporter data classes for experimental profiling signal type. (#6374)

Author: jhalliday

exporters/otlp/profiles/build.gradle.kts

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+plugins {
+  id("otel.java-conventions")
+  id("otel.publish-conventions")
+
+  id("otel.animalsniffer-conventions")
+}
+
+description = "OpenTelemetry - Profiles Exporter"
+otelJava.moduleName.set("io.opentelemetry.exporter.otlp.profiles")
+
+dependencies {
+  api(project(":sdk:common"))
+}

exporters/otlp/profiles/gradle.properties

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+otel.release=alpha

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/AggregationTemporality.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+/**
+ * Specifies the method of aggregating metric values.
+ *
+ * <p>TODO: This is intentionally not the same as metrics/AggregationTemporality. For profiles.proto
+ * 'v1experimental' version, this class is considered distinct from the pre-exiting
+ * AggregationTemporality in metrics.proto. As the profiles.proto stabilises, they may be refactored
+ * into a version in common.proto. Meanwhile the Java class structure reflects the .proto structure
+ * in making distinct entities.
+ *
+ * <p>refs for refactoring discussion:
+ *
+ * @see
+ *     "https://github.com/open-telemetry/opentelemetry-proto/blob/v1.3.0/opentelemetry/proto/metrics/v1/metrics.proto#L261"
+ * @see
+ *     "https://github.com/open-telemetry/opentelemetry-proto/blob/v1.3.0/opentelemetry/proto/profiles/v1experimental/pprofextended.proto#L147"
+ * @see "https://github.com/open-telemetry/opentelemetry-proto/issues/547"
+ * @see "https://github.com/open-telemetry/opentelemetry-proto/pull/534#discussion_r1552403726"
+ * @see "profiles.proto::AggregationTemporality"
+ */
+public enum AggregationTemporality {
+
+  /**
+   * DELTA is an AggregationTemporality for a profiler which reports changes since last report time.
+   */
+  DELTA,
+
+  /**
+   * CUMULATIVE is an AggregationTemporality for a profiler which reports changes since a fixed
+   * start time.
+   */
+  CUMULATIVE
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/AttributeUnitData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Represents a mapping between Attribute Keys and Units.
+ *
+ * @see "pprofextended.proto::AttributeUnit"
+ */
+@Immutable
+public interface AttributeUnitData {
+
+  /** Index into string table. */
+  long getAttributeKey();
+
+  /** Index into string table. */
+  long getUnitIndex();
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/BuildIdKind.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+/**
+ * Indicates the semantics of the build_id field.
+ *
+ * @see "pprofextended.proto::BuildIdKind"
+ */
+public enum BuildIdKind {
+
+  /** Linker-generated build ID, stored in the ELF binary notes. */
+  LINKER,
+
+  /** Build ID based on the content hash of the binary. */
+  BINARY_HASH;
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/FunctionData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Describes a function.
+ *
+ * @see "pprofextended.proto::Function"
+ */
+@Immutable
+public interface FunctionData {
+
+  /** Name of the function, in human-readable form if available. Index into string table. */
+  long getNameIndex();
+
+  /**
+   * Name of the function, as identified by the system. For instance, it can be a C++ mangled name.
+   * Index into string table.
+   */
+  long getSystemNameIndex();
+
+  /** Source file containing the function. Index into string table. */
+  long getFilenameIndex();
+
+  /** Line number in source file. */
+  long getStartLine();
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/LabelData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Provides additional context for a sample, such as thread ID or allocation size, with optional
+ * units.
+ *
+ * @see "pprofextended.proto::Label"
+ */
+@Immutable
+public interface LabelData {
+
+  /** Index into string table. */
+  long getKeyIndex();
+
+  /** String value of the label data, if applicable. Index into string table */
+  long getStrIndex();
+
+  /** Numeric value of the label data, if applicable. */
+  long getNum();
+
+  /**
+   * Specifies the units of num, applicable only if num is present. Use arbitrary string (for
+   * example, "requests") as a custom count unit.
+   */
+  long getNumUnitIndex();
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/LineData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Details a specific line in a source code, linked to a function.
+ *
+ * @see "pprofextended.proto::Line"
+ */
+@Immutable
+public interface LineData {
+
+  /** The index of the corresponding Function for this line. Index into function table. */
+  long getFunctionIndex();
+
+  /** Line number in source code. */
+  long getLine();
+
+  /** Column number in source code. */
+  long getColumn();
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/LinkData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A connection from a profile Sample to a trace Span.
+ *
+ * @see "pprofextended.proto::Link"
+ */
+@Immutable
+public interface LinkData {
+
+  /**
+   * Returns a unique identifier of a trace that this linked span is part of as 32 character
+   * lowercase hex String.
+   */
+  String getTraceId();
+
+  /** Returns a unique identifier for the linked span, as 16 character lowercase hex String. */
+  String getSpanId();
+}

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/LocationData.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.otlp.profiles;
+
+import java.util.List;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Describes a function.
+ *
+ * @see "pprofextended.proto::Location"
+ */
+@Immutable
+public interface LocationData {
+
+  /**
+   * The index of the corresponding profile.Mapping for this location. It can be unset if the
+   * mapping is unknown or not applicable for this profile type.
+   */
+  long getMappingIndex();
+
+  /** The instruction address for this location, if available. */
+  long getAddress();
+
+  /**
+   * Multiple line indicates this location has inlined functions, where the last entry represents
+   * the caller into which the preceding entries were inlined.
+   */
+  List<LineData> getLines();
+
+  /**
+   * Provides an indication that multiple symbols map to this location's address, for example due to
+   * identical code folding by the linker.
+   */
+  boolean isFolded();
+
+  /** Type of frame (e.g. kernel, native, python, hotspot, php). Index into string table. */
+  int getTypeIndex();
+
+  /** References to attributes in Profile.attribute_table. */
+  List<Long> getAttributes();
+}