feat: allow session pool settings in connection url

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPoolOptions.java

@@ -18,6 +18,7 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import java.util.Objects;
 import org.threeten.bp.Duration;
 
 /** Options for the session pool used by {@code DatabaseClient}. */
@@ -63,6 +64,48 @@ private SessionPoolOptions(Builder builder) {
     this.removeInactiveSessionAfter = builder.removeInactiveSessionAfter;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof SessionPoolOptions)) {
+      return false;
+    }
+    SessionPoolOptions other = (SessionPoolOptions) o;
+    return Objects.equals(this.minSessions, other.minSessions)
+        && Objects.equals(this.maxSessions, other.maxSessions)
+        && Objects.equals(this.incStep, other.incStep)
+        && Objects.equals(this.maxIdleSessions, other.maxIdleSessions)
+        && Objects.equals(this.writeSessionsFraction, other.writeSessionsFraction)
+        && Objects.equals(this.actionOnExhaustion, other.actionOnExhaustion)
+        && Objects.equals(this.actionOnSessionNotFound, other.actionOnSessionNotFound)
+        && Objects.equals(this.actionOnSessionLeak, other.actionOnSessionLeak)
+        && Objects.equals(
+            this.initialWaitForSessionTimeoutMillis, other.initialWaitForSessionTimeoutMillis)
+        && Objects.equals(this.loopFrequency, other.loopFrequency)
+        && Objects.equals(this.keepAliveIntervalMinutes, other.keepAliveIntervalMinutes)
+        && Objects.equals(this.removeInactiveSessionAfter, other.removeInactiveSessionAfter);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(
+        this.minSessions,
+        this.maxSessions,
+        this.incStep,
+        this.maxIdleSessions,
+        this.writeSessionsFraction,
+        this.actionOnExhaustion,
+        this.actionOnSessionNotFound,
+        this.actionOnSessionLeak,
+        this.initialWaitForSessionTimeoutMillis,
+        this.loopFrequency,
+        this.keepAliveIntervalMinutes,
+        this.removeInactiveSessionAfter);
+  }
+
+  public Builder toBuilder() {
+    return new Builder(this);
+  }
+
   public int getMinSessions() {
     return minSessions;
   }
@@ -165,6 +208,24 @@ public static class Builder {
     private int keepAliveIntervalMinutes = 30;
     private Duration removeInactiveSessionAfter = Duration.ofMinutes(55L);
 
+    public Builder() {}
+
+    private Builder(SessionPoolOptions options) {
+      this.minSessionsSet = true;
+      this.minSessions = options.minSessions;
+      this.maxSessions = options.maxSessions;
+      this.incStep = options.incStep;
+      this.maxIdleSessions = options.maxIdleSessions;
+      this.writeSessionsFraction = options.writeSessionsFraction;
+      this.actionOnExhaustion = options.actionOnExhaustion;
+      this.initialWaitForSessionTimeoutMillis = options.initialWaitForSessionTimeoutMillis;
+      this.actionOnSessionNotFound = options.actionOnSessionNotFound;
+      this.actionOnSessionLeak = options.actionOnSessionLeak;
+      this.loopFrequency = options.loopFrequency;
+      this.keepAliveIntervalMinutes = options.keepAliveIntervalMinutes;
+      this.removeInactiveSessionAfter = options.removeInactiveSessionAfter;
+    }
+
     /**
      * Minimum number of sessions that this pool will always maintain. These will be created eagerly
      * in parallel. Defaults to 100.

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java

@@ -150,6 +150,8 @@ public String[] getValidValues() {
   static final boolean DEFAULT_RETRY_ABORTS_INTERNALLY = true;
   private static final String DEFAULT_CREDENTIALS = null;
   private static final String DEFAULT_OAUTH_TOKEN = null;
+  private static final String DEFAULT_MIN_SESSIONS = null;
+  private static final String DEFAULT_MAX_SESSIONS = null;
   private static final String DEFAULT_NUM_CHANNELS = null;
   private static final String DEFAULT_USER_AGENT = null;
   private static final String DEFAULT_OPTIMIZER_VERSION = "";
@@ -172,6 +174,10 @@ public String[] getValidValues() {
    * OAuth token to use for authentication. Cannot be used in combination with a credentials file.
    */
   public static final String OAUTH_TOKEN_PROPERTY_NAME = "oauthToken";
+  /** Name of the 'minSessions' connection property. */
+  public static final String MIN_SESSIONS_PROPERTY_NAME = "minSessions";
+  /** Name of the 'numChannels' connection property. */
+  public static final String MAX_SESSIONS_PROPERTY_NAME = "maxSessions";
   /** Name of the 'numChannels' connection property. */
   public static final String NUM_CHANNELS_PROPERTY_NAME = "numChannels";
   /** Custom user agent string is only for other Google libraries. */
@@ -204,6 +210,12 @@ public String[] getValidValues() {
                   ConnectionProperty.createStringProperty(
                       OAUTH_TOKEN_PROPERTY_NAME,
                       "A valid pre-existing OAuth token to use for authentication for this connection. Setting this property will take precedence over any value set for a credentials file."),
+                  ConnectionProperty.createStringProperty(
+                      MIN_SESSIONS_PROPERTY_NAME,
+                      "The minimum number of sessions in the backing session pool. The default is 100."),
+                  ConnectionProperty.createStringProperty(
+                      MAX_SESSIONS_PROPERTY_NAME,
+                      "The maximum number of sessions in the backing session pool. The default is 400."),
                   ConnectionProperty.createStringProperty(
                       NUM_CHANNELS_PROPERTY_NAME,
                       "The number of gRPC channels to use to communicate with Cloud Spanner. The default is 4."),
@@ -327,6 +339,9 @@ private boolean isValidUri(String uri) {
      *       true.
      *   <li>readonly (boolean): Sets the initial readonly mode for the connection. Default is
      *       false.
+     *   <li>minSessions (int): Sets the minimum number of sessions in the backing session pool.
+     *   <li>maxSessions (int): Sets the maximum number of sessions in the backing session pool.
+     *   <li>numChannels (int): Sets the number of gRPC channels to use for the connection.
      *   <li>retryAbortsInternally (boolean): Sets the initial retryAbortsInternally mode for the
      *       connection. Default is true.
      *   <li>optimizerVersion (string): Sets the query optimizer version to use for the connection.
@@ -437,6 +452,8 @@ public static Builder newBuilder() {
   private final Credentials credentials;
   private final SessionPoolOptions sessionPoolOptions;
   private final Integer numChannels;
+  private final Integer minSessions;
+  private final Integer maxSessions;
   private final String userAgent;
   private final QueryOptions queryOptions;
 
@@ -453,7 +470,6 @@ private ConnectionOptions(Builder builder) {
     this.warnings = checkValidProperties(builder.uri);
 
     this.uri = builder.uri;
-    this.sessionPoolOptions = builder.sessionPoolOptions;
     this.credentialsUrl =
         builder.credentialsUrl != null ? builder.credentialsUrl : parseCredentials(builder.uri);
     this.oauthToken =
@@ -492,19 +508,12 @@ private ConnectionOptions(Builder builder) {
     } else {
       this.credentials = getCredentialsService().createCredentials(this.credentialsUrl);
     }
-    String numChannelsValue = parseNumChannels(builder.uri);
-    if (numChannelsValue != null) {
-      try {
-        this.numChannels = Integer.valueOf(numChannelsValue);
-      } catch (NumberFormatException e) {
-        throw SpannerExceptionFactory.newSpannerException(
-            ErrorCode.INVALID_ARGUMENT,
-            "Invalid numChannels value specified: " + numChannelsValue,
-            e);
-      }
-    } else {
-      this.numChannels = null;
-    }
+    this.minSessions =
+        parseIntegerProperty(MIN_SESSIONS_PROPERTY_NAME, parseMinSessions(builder.uri));
+    this.maxSessions =
+        parseIntegerProperty(MAX_SESSIONS_PROPERTY_NAME, parseMaxSessions(builder.uri));
+    this.numChannels =
+        parseIntegerProperty(NUM_CHANNELS_PROPERTY_NAME, parseNumChannels(builder.uri));
 
     String projectId = matcher.group(Builder.PROJECT_GROUP);
     if (Builder.DEFAULT_PROJECT_ID_PLACEHOLDER.equalsIgnoreCase(projectId)) {
@@ -518,6 +527,36 @@ private ConnectionOptions(Builder builder) {
     this.statementExecutionInterceptors =
         Collections.unmodifiableList(builder.statementExecutionInterceptors);
     this.configurator = builder.configurator;
+
+    if (this.minSessions != null || this.maxSessions != null) {
+      SessionPoolOptions.Builder sessionPoolOptionsBuilder =
+          builder.sessionPoolOptions == null
+              ? SessionPoolOptions.newBuilder()
+              : builder.sessionPoolOptions.toBuilder();
+      if (this.minSessions != null) {
+        sessionPoolOptionsBuilder.setMinSessions(this.minSessions);
+      }
+      if (this.maxSessions != null) {
+        sessionPoolOptionsBuilder.setMaxSessions(this.maxSessions);
+      }
+      this.sessionPoolOptions = sessionPoolOptionsBuilder.build();
+    } else {
+      this.sessionPoolOptions = builder.sessionPoolOptions;
+    }
+  }
+
+  private static Integer parseIntegerProperty(String propertyName, String value) {
+    if (value != null) {
+      try {
+        return Integer.valueOf(value);
+      } catch (NumberFormatException e) {
+        throw SpannerExceptionFactory.newSpannerException(
+            ErrorCode.INVALID_ARGUMENT,
+            String.format("Invalid %s value specified: %s", propertyName, value),
+            e);
+      }
+    }
+    return null;
   }
 
   SpannerOptionsConfigurator getConfigurator() {
@@ -565,6 +604,18 @@ static String parseOAuthToken(String uri) {
     return value != null ? value : DEFAULT_OAUTH_TOKEN;
   }
 
+  @VisibleForTesting
+  static String parseMinSessions(String uri) {
+    String value = parseUriProperty(uri, MIN_SESSIONS_PROPERTY_NAME);
+    return value != null ? value : DEFAULT_MIN_SESSIONS;
+  }
+
+  @VisibleForTesting
+  static String parseMaxSessions(String uri) {
+    String value = parseUriProperty(uri, MAX_SESSIONS_PROPERTY_NAME);
+    return value != null ? value : DEFAULT_MAX_SESSIONS;
+  }
+
   @VisibleForTesting
   static String parseNumChannels(String uri) {
     String value = parseUriProperty(uri, NUM_CHANNELS_PROPERTY_NAME);
@@ -671,6 +722,24 @@ public SessionPoolOptions getSessionPoolOptions() {
     return sessionPoolOptions;
   }
 
+  /**
+   * The minimum number of sessions in the backing session pool of this connection. The session pool
+   * is shared between all connections in the same JVM that connect to the same Cloud Spanner
+   * database using the same connection settings.
+   */
+  public Integer getMinSessions() {
+    return minSessions;
+  }
+
+  /**
+   * The maximum number of sessions in the backing session pool of this connection. The session pool
+   * is shared between all connections in the same JVM that connect to the same Cloud Spanner
+   * database using the same connection settings.
+   */
+  public Integer getMaxSessions() {
+    return maxSessions;
+  }
+
   /** The number of channels to use for the connection. */
   public Integer getNumChannels() {
     return numChannels;

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java

@@ -148,15 +148,19 @@ static class SpannerPoolKey {
     private final boolean usePlainText;
     private final String userAgent;
 
-    private static SpannerPoolKey of(ConnectionOptions options) {
+    @VisibleForTesting
+    static SpannerPoolKey of(ConnectionOptions options) {
       return new SpannerPoolKey(options);
     }
 
     private SpannerPoolKey(ConnectionOptions options) {
       this.host = options.getHost();
       this.projectId = options.getProjectId();
       this.credentialsKey = CredentialsKey.create(options);
-      this.sessionPoolOptions = options.getSessionPoolOptions();
+      this.sessionPoolOptions =
+          options.getSessionPoolOptions() == null
+              ? SessionPoolOptions.newBuilder().build()
+              : options.getSessionPoolOptions();
       this.numChannels = options.getNumChannels();
       this.usePlainText = options.isUsePlainText();
       this.userAgent = options.getUserAgent();

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionOptionsTest.java

@@ -421,4 +421,28 @@ public void testLenient() {
       assertThat(e.getMessage()).contains("bar");
     }
   }
+
+  @Test
+  public void testMinSessions() {
+    ConnectionOptions options =
+        ConnectionOptions.newBuilder()
+            .setUri(
+                "cloudspanner:/projects/test-project-123/instances/test-instance/databases/test-database?minSessions=400")
+            .setCredentialsUrl(FILE_TEST_PATH)
+            .build();
+    assertThat(options.getMinSessions()).isEqualTo(400);
+    assertThat(options.getSessionPoolOptions().getMinSessions()).isEqualTo(400);
+  }
+
+  @Test
+  public void testMaxSessions() {
+    ConnectionOptions options =
+        ConnectionOptions.newBuilder()
+            .setUri(
+                "cloudspanner:/projects/test-project-123/instances/test-instance/databases/test-database?maxSessions=4000")
+            .setCredentialsUrl(FILE_TEST_PATH)
+            .build();
+    assertThat(options.getMaxSessions()).isEqualTo(4000);
+    assertThat(options.getSessionPoolOptions().getMaxSessions()).isEqualTo(4000);
+  }
 }