Support output_stream in declarative config of otlp_file/development

CHANGELOG.md

@@ -95,6 +95,8 @@ exporter.
   ([#8609](https://github.com/open-telemetry/opentelemetry-java/pull/8609))
 * Logging: Include aggregation temporality in `LoggingMetricExporter` `toString`
   ([#8623](https://github.com/open-telemetry/opentelemetry-java/pull/8623))
+* Logging: Support the `output_stream` option when declaratively configuring `otlp_file/development`
+  ([#8676](https://github.com/open-telemetry/opentelemetry-java/pull/8676))
 
 #### Extensions
 

exporters/logging-otlp/src/main/java/io/opentelemetry/exporter/logging/otlp/internal/OutputStreamConfigUtil.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.logging.otlp.internal;
+
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException;
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.file.FileSystemNotFoundException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.util.function.Consumer;
+
+/**
+ * Utilities for configuring the output stream of the OTLP file exporters.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+public final class OutputStreamConfigUtil {
+
+  private static final String STDOUT = "stdout";
+  private static final String FILE_SCHEME = "file";
+
+  /**
+   * Invoke the {@code outputStreamConsumer} with the configured output stream.
+   *
+   * <p>Recognized values are {@code stdout} and a file URI such as {@code
+   * file:///path/to/file.jsonl}. Missing parent directories of the file are created, and the file
+   * is appended to if it already exists.
+   */
+  @SuppressWarnings("SystemOut")
+  public static void configureOutputStream(
+      DeclarativeConfigProperties config, Consumer<OutputStream> outputStreamConsumer) {
+    String outputStream = config.getString("output_stream");
+    if (outputStream == null) {
+      return;
+    }
+    if (STDOUT.equalsIgnoreCase(outputStream)) {
+      outputStreamConsumer.accept(System.out);
+      return;
+    }
+    Path path = filePath(outputStream);
+    try {
+      Path parent = path.getParent();
+      if (parent != null) {
+        Files.createDirectories(parent);
+      }
+      outputStreamConsumer.accept(
+          new BufferedOutputStream(
+              Files.newOutputStream(path, StandardOpenOption.CREATE, StandardOpenOption.APPEND)));
+    } catch (IOException e) {
+      throw new ConfigurationException("Unable to open output_stream: " + outputStream, e);
+    }
+  }
+
+  private static Path filePath(String outputStream) {
+    URI uri;
+    try {
+      uri = new URI(outputStream);
+    } catch (URISyntaxException e) {
+      throw new ConfigurationException("Unrecognized output_stream: " + outputStream, e);
+    }
+    if (!FILE_SCHEME.equalsIgnoreCase(uri.getScheme())) {
+      throw new ConfigurationException("Unrecognized output_stream: " + outputStream);
+    }
+    try {
+      return Paths.get(uri);
+    } catch (IllegalArgumentException | FileSystemNotFoundException e) {
+      throw new ConfigurationException("Unrecognized output_stream: " + outputStream, e);
+    }
+  }
+
+  private OutputStreamConfigUtil() {}
+}

exporters/logging-otlp/src/main/java/io/opentelemetry/exporter/logging/otlp/internal/logs/OtlpStdoutLogRecordExporterComponentProvider.java

@@ -7,6 +7,7 @@
 
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.exporter.internal.IncubatingExporterBuilderUtil;
+import io.opentelemetry.exporter.logging.otlp.internal.OutputStreamConfigUtil;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
 import io.opentelemetry.sdk.logs.export.LogRecordExporter;
 
@@ -32,6 +33,7 @@ public String getName() {
   public LogRecordExporter create(DeclarativeConfigProperties config) {
     OtlpStdoutLogRecordExporterBuilder builder = OtlpStdoutLogRecordExporter.builder();
     IncubatingExporterBuilderUtil.configureExporterMemoryMode(config, builder::setMemoryMode);
+    OutputStreamConfigUtil.configureOutputStream(config, builder::setOutput);
     return builder.build();
   }
 }

exporters/logging-otlp/src/main/java/io/opentelemetry/exporter/logging/otlp/internal/metrics/OtlpStdoutMetricExporterComponentProvider.java

@@ -7,6 +7,7 @@
 
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.exporter.internal.IncubatingExporterBuilderUtil;
+import io.opentelemetry.exporter.logging.otlp.internal.OutputStreamConfigUtil;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 
@@ -36,6 +37,7 @@ public MetricExporter create(DeclarativeConfigProperties config) {
         config, builder::setAggregationTemporalitySelector);
     IncubatingExporterBuilderUtil.configureOtlpHistogramDefaultAggregation(
         config, builder::setDefaultAggregationSelector);
+    OutputStreamConfigUtil.configureOutputStream(config, builder::setOutput);
     return builder.build();
   }
 }

exporters/logging-otlp/src/main/java/io/opentelemetry/exporter/logging/otlp/internal/traces/OtlpStdoutSpanExporterComponentProvider.java

@@ -7,6 +7,7 @@
 
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.exporter.internal.IncubatingExporterBuilderUtil;
+import io.opentelemetry.exporter.logging.otlp.internal.OutputStreamConfigUtil;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 
@@ -32,6 +33,7 @@ public String getName() {
   public SpanExporter create(DeclarativeConfigProperties config) {
     OtlpStdoutSpanExporterBuilder builder = OtlpStdoutSpanExporter.builder();
     IncubatingExporterBuilderUtil.configureExporterMemoryMode(config, builder::setMemoryMode);
+    OutputStreamConfigUtil.configureOutputStream(config, builder::setOutput);
     return builder.build();
   }
 }

exporters/logging-otlp/src/test/java/io/opentelemetry/exporter/logging/otlp/AbstractOtlpStdoutExporterTest.java

@@ -16,6 +16,7 @@
 import io.github.netmikey.logunit.api.LogCapturer;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
 import io.opentelemetry.sdk.common.export.MemoryMode;
@@ -30,6 +31,7 @@
 import java.nio.file.Path;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
+import java.util.function.UnaryOperator;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 import javax.annotation.Nullable;
@@ -302,6 +304,92 @@ void componentProviderConfig() {
         .isEqualTo(MemoryMode.REUSABLE_DATA);
   }
 
+  static Stream<Arguments> outputStreamStdoutTestCases() {
+    return Stream.of(
+        Arguments.argumentSet("stdout", "stdout"), Arguments.argumentSet("upper case", "STDOUT"));
+  }
+
+  @ParameterizedTest
+  @MethodSource("outputStreamStdoutTestCases")
+  void componentProviderConfigOutputStreamStdout(String value) {
+    DeclarativeConfigProperties properties = spy(DeclarativeConfigProperties.empty());
+    when(properties.getString("output_stream")).thenReturn(value);
+
+    assertThat(exporterFromComponentProvider(properties))
+        .extracting("jsonWriter")
+        .extracting(Object::toString)
+        .isEqualTo("StreamJsonWriter{outputStream=stdout}");
+  }
+
+  static Stream<Arguments> outputStreamFileTestCases() {
+    return Stream.of(
+        Arguments.argumentSet("file uri", "test.jsonl", (UnaryOperator<String>) uri -> uri),
+        Arguments.argumentSet(
+            "authority-less file uri with upper case scheme",
+            "test.jsonl",
+            (UnaryOperator<String>) uri -> uri.replaceFirst("^file://", "FILE:")),
+        Arguments.argumentSet(
+            "missing parent directory", "missing/test.jsonl", (UnaryOperator<String>) uri -> uri));
+  }
+
+  @ParameterizedTest
+  @MethodSource("outputStreamFileTestCases")
+  void componentProviderConfigOutputStreamFile(String relativePath, UnaryOperator<String> uriForm)
+      throws Exception {
+    Path file = tempDir.resolve(relativePath);
+    DeclarativeConfigProperties properties = spy(DeclarativeConfigProperties.empty());
+    when(properties.getString("output_stream")).thenReturn(uriForm.apply(file.toUri().toString()));
+
+    T exporter = exporterFromComponentProvider(properties);
+    testDataExporter.export(exporter);
+
+    String output = new String(Files.readAllBytes(file), StandardCharsets.UTF_8).trim();
+    JSONAssert.assertEquals(
+        "Got \n" + output,
+        testDataExporter.getExpectedJson(/* withWrapper= */ true),
+        output,
+        false);
+
+    // an exporter created later for the same path appends instead of truncating
+    testDataExporter.shutdown(exporter);
+    T secondExporter = exporterFromComponentProvider(properties);
+    testDataExporter.export(secondExporter);
+    testDataExporter.shutdown(secondExporter);
+    assertThat(new String(Files.readAllBytes(file), StandardCharsets.UTF_8).trim().split("\n"))
+        .hasSize(2);
+  }
+
+  static Stream<Arguments> outputStreamUnrecognizedTestCases() {
+    return Stream.of(
+        Arguments.argumentSet("no scheme", "not-a-stream"),
+        Arguments.argumentSet("unsupported scheme", "http://example.com/traces.jsonl"),
+        Arguments.argumentSet("relative file uri", "file://traces.jsonl"),
+        Arguments.argumentSet("malformed file uri", "file:///with space.jsonl"));
+  }
+
+  @ParameterizedTest
+  @MethodSource("outputStreamUnrecognizedTestCases")
+  void componentProviderConfigOutputStreamUnrecognized(String value) {
+    DeclarativeConfigProperties properties = spy(DeclarativeConfigProperties.empty());
+    when(properties.getString("output_stream")).thenReturn(value);
+
+    assertThatExceptionOfType(ConfigurationException.class)
+        .isThrownBy(() -> exporterFromComponentProvider(properties))
+        .withMessage("Unrecognized output_stream: " + value);
+  }
+
+  @Test
+  void componentProviderConfigOutputStreamNotOpenable() {
+    DeclarativeConfigProperties properties = spy(DeclarativeConfigProperties.empty());
+    // the path exists but is a directory, so it cannot be opened for writing
+    when(properties.getString("output_stream")).thenReturn(tempDir.toUri().toString());
+
+    assertThatExceptionOfType(ConfigurationException.class)
+        .isThrownBy(() -> exporterFromComponentProvider(properties))
+        .withMessageStartingWith("Unable to open output_stream: ")
+        .withCauseInstanceOf(IOException.class);
+  }
+
   @SuppressWarnings("unchecked")
   protected T exporterFromComponentProvider(DeclarativeConfigProperties properties) {
     return (T)

sdk-extensions/declarative-config/src/test/java/io/opentelemetry/sdk/autoconfigure/declarativeconfig/DeclarativeConfigurationCreateTest.java

@@ -96,6 +96,11 @@ void parseAndCreate_Examples(File example, @TempDir Path tempDir)
                 "cert_file: "
                     + clientCertificatePath.replace("\\", "\\\\")
                     + System.lineSeparator())
+            // Snippets write to file:///var/log/*.jsonl, which is not writable in tests. The
+            // value can be the last line of the file, so the line terminator is not matched.
+            .replaceAll(
+                "output_stream: file:.*",
+                "output_stream: " + tempDir.resolve("output.jsonl").toUri())
             // A snippet references a custom id generator named my_custom_id_generator. Replace with
             // one named test, which we provide via SPI
             .replace("my_custom_id_generator", "test");