SERVER-69871 Move feature_flag unit into server_base

1 files changed, 192 insertions, 0 deletions

diff --git a/src/mongo/db/feature_compatibility_version_parser.cpp b/src/mongo/db/feature_compatibility_version_parser.cpp
new file mode 100644
index 00000000000..ef039ce158a
--- /dev/null
+++ b/src/mongo/db/feature_compatibility_version_parser.cpp
@@ -0,0 +1,192 @@
+/**
+ *    Copyright (C) 2018-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/feature_compatibility_version_parser.h"
+
+#include "mongo/base/status.h"
+#include "mongo/bson/bsonobj.h"
+#include "mongo/db/feature_compatibility_version_document_gen.h"
+#include "mongo/db/feature_compatibility_version_documentation.h"
+#include "mongo/db/namespace_string.h"
+#include "mongo/util/version/releases.h"
+
+namespace mongo {
+
+using GenericFCV = multiversion::GenericFCV;
+
+multiversion::FeatureCompatibilityVersion FeatureCompatibilityVersionParser::parseVersion(
+    StringData versionString) {
+    if (versionString == multiversion::toString(GenericFCV::kLastLTS)) {
+        return GenericFCV::kLastLTS;
+    }
+    if (versionString == multiversion::toString(GenericFCV::kLastContinuous)) {
+        return GenericFCV::kLastContinuous;
+    }
+    if (versionString == multiversion::toString(GenericFCV::kLatest)) {
+        return GenericFCV::kLatest;
+    }
+
+    uasserted(4926900,
+              str::stream() << "Invalid feature compatibility version value, expected '"
+                            << multiversion::toString(GenericFCV::kLastLTS) << "' or '"
+                            << multiversion::toString(GenericFCV::kLastContinuous) << "' or '"
+                            << multiversion::toString(GenericFCV::kLatest) << ". See "
+                            << feature_compatibility_version_documentation::kCompatibilityLink
+                            << ".");
+}
+
+multiversion::FeatureCompatibilityVersion
+FeatureCompatibilityVersionParser::parseVersionForFeatureFlags(StringData versionString) {
+    return multiversion::parseVersionForFeatureFlags(versionString);
+}
+
+StringData FeatureCompatibilityVersionParser::serializeVersion(
+    multiversion::FeatureCompatibilityVersion version) {
+    invariant(version == GenericFCV::kLastLTS || version == GenericFCV::kLastContinuous ||
+                  version == GenericFCV::kLatest,
+              "Invalid feature compatibility version value");
+
+    return multiversion::toString(version);
+}
+
+StringData FeatureCompatibilityVersionParser::serializeVersionForFeatureFlags(
+    multiversion::FeatureCompatibilityVersion version) {
+    if (multiversion::isStandardFCV(version)) {
+        return multiversion::toString(version);
+    }
+
+    uasserted(ErrorCodes::BadValue,
+              fmt::format("Invalid FCV version {} for feature flag.", version));
+}
+
+Status FeatureCompatibilityVersionParser::validatePreviousVersionField(
+    multiversion::FeatureCompatibilityVersion version) {
+    if (version == GenericFCV::kLatest) {
+        return Status::OK();
+    }
+    return Status(ErrorCodes::Error(4926901),
+                  "when present, 'previousVersion' field must be the latest binary version");
+}
+
+StatusWith<multiversion::FeatureCompatibilityVersion> FeatureCompatibilityVersionParser::parse(
+    const BSONObj& featureCompatibilityVersionDoc) {
+    try {
+        auto fcvDoc = FeatureCompatibilityVersionDocument::parse(
+            IDLParserContext("FeatureCompatibilityVersionParser"), featureCompatibilityVersionDoc);
+        auto version = fcvDoc.getVersion();
+        auto targetVersion = fcvDoc.getTargetVersion();
+        auto previousVersion = fcvDoc.getPreviousVersion();
+
+        // Downgrading FCV.
+        if ((version == GenericFCV::kLastLTS || version == GenericFCV::kLastContinuous) &&
+            version == targetVersion) {
+            // Downgrading FCV must have a "previousVersion" field.
+            if (!previousVersion) {
+                return Status(ErrorCodes::Error(4926902),
+                              str::stream()
+                                  << "Missing field "
+                                  << FeatureCompatibilityVersionDocument::kPreviousVersionFieldName
+                                  << " in downgrading states for " << multiversion::kParameterName
+                                  << " document in "
+                                  << NamespaceString::kServerConfigurationNamespace.toString()
+                                  << ": " << featureCompatibilityVersionDoc << ". See "
+                                  << feature_compatibility_version_documentation::kCompatibilityLink
+                                  << ".");
+            }
+            if (version == GenericFCV::kLastLTS) {
+                // Downgrading to last-lts.
+                return GenericFCV::kDowngradingFromLatestToLastLTS;
+            } else {
+                return GenericFCV::kDowngradingFromLatestToLastContinuous;
+            }
+        }
+
+        // Non-downgrading FCV must not have a "previousVersion" field.
+        if (previousVersion) {
+            return Status(ErrorCodes::Error(4926903),
+                          str::stream()
+                              << "Unexpected field "
+                              << FeatureCompatibilityVersionDocument::kPreviousVersionFieldName
+                              << " in non-downgrading states for " << multiversion::kParameterName
+                              << " document in "
+                              << NamespaceString::kServerConfigurationNamespace.toString() << ": "
+                              << featureCompatibilityVersionDoc << ". See "
+                              << feature_compatibility_version_documentation::kCompatibilityLink
+                              << ".");
+        }
+
+        // Upgrading FCV.
+        if (targetVersion) {
+            // For upgrading FCV, "targetVersion" must be kLatest or kLastContinuous and "version"
+            // must be kLastContinuous or kLastLTS.
+            if (targetVersion == GenericFCV::kLastLTS || version == GenericFCV::kLatest) {
+                return Status(ErrorCodes::Error(4926904),
+                              str::stream()
+                                  << "Invalid " << multiversion::kParameterName << " document in "
+                                  << NamespaceString::kServerConfigurationNamespace.toString()
+                                  << ": " << featureCompatibilityVersionDoc << ". See "
+                                  << feature_compatibility_version_documentation::kCompatibilityLink
+                                  << ".");
+            }
+
+            if (version == GenericFCV::kLastLTS) {
+                return targetVersion == GenericFCV::kLastContinuous
+                    ? GenericFCV::kUpgradingFromLastLTSToLastContinuous
+                    : GenericFCV::kUpgradingFromLastLTSToLatest;
+            } else {
+                uassert(5070601,
+                        str::stream()
+                            << "Invalid " << multiversion::kParameterName << " document in "
+                            << NamespaceString::kServerConfigurationNamespace.toString() << ": "
+                            << featureCompatibilityVersionDoc << ". See "
+                            << feature_compatibility_version_documentation::kCompatibilityLink
+                            << ".",
+                        version == GenericFCV::kLastContinuous);
+                return GenericFCV::kUpgradingFromLastContinuousToLatest;
+            }
+        }
+
+        // No "targetVersion" or "previousVersion" field.
+        return version;
+    } catch (const DBException& e) {
+        auto status = e.toStatus();
+        status.addContext(str::stream()
+                          << "Invalid " << multiversion::kParameterName << " document in "
+                          << NamespaceString::kServerConfigurationNamespace.toString() << ": "
+                          << featureCompatibilityVersionDoc << ". See "
+                          << feature_compatibility_version_documentation::kCompatibilityLink
+                          << ".");
+        return status;
+    }
+    MONGO_UNREACHABLE
+}
+
+}  // namespace mongo