Add config option for connection string (#56)

Author: nirinchev

src/config.ts

@@ -4,21 +4,34 @@ import argv from "yargs-parser";
 
 import packageJson from "../package.json" with { type: "json" };
 import fs from "fs";
+import { ReadConcernLevel, ReadPreferenceMode, W } from "mongodb";
 const { localDataPath, configPath } = getLocalDataPath();
 
 // If we decide to support non-string config options, we'll need to extend the mechanism for parsing
 // env variables.
-interface UserConfig extends Record<string, string | undefined> {
+interface UserConfig {
     apiBaseUrl: string;
     clientId: string;
     stateFile: string;
     connectionString?: string;
+    connectOptions: {
+        readConcern: ReadConcernLevel;
+        readPreference: ReadPreferenceMode;
+        writeConcern: W;
+        timeoutMS: number;
+    };
 }
 
 const defaults: UserConfig = {
     apiBaseUrl: "https://cloud.mongodb.com/",
     clientId: "0oabtxactgS3gHIR0297",
     stateFile: path.join(localDataPath, "state.json"),
+    connectOptions: {
+        readConcern: "local",
+        readPreference: "secondaryPreferred",
+        writeConcern: "majority",
+        timeoutMS: 30_000,
+    },
 };
 
 const mergedUserConfig = {
@@ -66,21 +79,52 @@ function getLocalDataPath(): { localDataPath: string; configPath: string } {
 // are prefixed with `MDB_MCP_` and the keys match the UserConfig keys, but are converted
 // to SNAKE_UPPER_CASE.
 function getEnvConfig(): Partial<UserConfig> {
-    const camelCaseToSNAKE_UPPER_CASE = (str: string): string => {
-        return str.replace(/([a-z])([A-Z])/g, "$1_$2").toUpperCase();
-    };
+    function setValue(obj: Record<string, unknown>, path: string[], value: string): void {
+        const currentField = path.shift()!;
+        if (path.length === 0) {
+            const numberValue = Number(value);
+            if (!isNaN(numberValue)) {
+                obj[currentField] = numberValue;
+                return;
+            }
+
+            const booleanValue = value.toLocaleLowerCase();
+            if (booleanValue === "true" || booleanValue === "false") {
+                obj[currentField] = booleanValue === "true";
+                return;
+            }
+
+            obj[currentField] = value;
+            return;
+        }
 
-    const result: Partial<UserConfig> = {};
-    for (const key of Object.keys(defaults)) {
-        const envVarName = `MDB_MCP_${camelCaseToSNAKE_UPPER_CASE(key)}`;
-        if (process.env[envVarName]) {
-            result[key] = process.env[envVarName];
+        if (!obj[currentField]) {
+            obj[currentField] = {};
         }
+
+        setValue(obj[currentField] as Record<string, unknown>, path, value);
+    }
+
+    const result: Record<string, unknown> = {};
+    const mcpVariables = Object.entries(process.env).filter(
+        ([key, value]) => value !== undefined && key.startsWith("MDB_MCP_")
+    ) as [string, string][];
+    for (const [key, value] of mcpVariables) {
+        const fieldPath = key
+            .replace("MDB_MCP_", "")
+            .split(".")
+            .map((part) => SNAKE_CASE_toCamelCase(part));
+
+        setValue(result, fieldPath, value);
     }
 
     return result;
 }
 
+function SNAKE_CASE_toCamelCase(str: string): string {
+    return str.toLowerCase().replace(/([-_][a-z])/g, (group) => group.toUpperCase().replace("_", ""));
+}
+
 // Gets the config supplied by the user as a JSON file. The file is expected to be located in the local data path
 // and named `config.json`.
 function getFileConfig(): Partial<UserConfig> {

src/tools/mongodb/collectionIndexes.ts

@@ -9,7 +9,7 @@ export class CollectionIndexesTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "read";
 
     protected async execute({ database, collection }: ToolArgs<typeof DbOperationArgs>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const indexes = await provider.getIndexes(database, collection);
 
         return {

src/tools/mongodb/connect.ts

@@ -1,6 +1,5 @@
 import { z } from "zod";
 import { CallToolResult } from "@modelcontextprotocol/sdk/types.js";
-import { NodeDriverServiceProvider } from "@mongosh/service-provider-node-driver";
 import { DbOperationType, MongoDBToolBase } from "./mongodbTool.js";
 import { ToolArgs } from "../tool.js";
 import { ErrorCodes, MongoDBError } from "../../errors.js";
@@ -58,21 +57,10 @@ export class ConnectTool extends MongoDBToolBase {
             throw new MongoDBError(ErrorCodes.InvalidParams, "Invalid connection options");
         }
 
-        await this.connect(connectionString);
+        await this.connectToMongoDB(connectionString, this.state);
 
         return {
             content: [{ type: "text", text: `Successfully connected to ${connectionString}.` }],
         };
     }
-
-    private async connect(connectionString: string): Promise<void> {
-        const provider = await NodeDriverServiceProvider.connect(connectionString, {
-            productDocsLink: "https://docs.mongodb.com/todo-mcp",
-            productName: "MongoDB MCP",
-        });
-
-        this.state.serviceProvider = provider;
-        this.state.credentials.connectionString = connectionString;
-        await this.state.persistCredentials();
-    }
 }

src/tools/mongodb/create/insertMany.ts

@@ -21,7 +21,7 @@ export class InsertManyTool extends MongoDBToolBase {
         collection,
         documents,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.insertMany(database, collection, documents);
 
         return {

src/tools/mongodb/create/insertOne.ts

@@ -23,7 +23,7 @@ export class InsertOneTool extends MongoDBToolBase {
         collection,
         document,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.insertOne(database, collection, document);
 
         return {

src/tools/mongodb/createIndex.ts

@@ -15,7 +15,7 @@ export class CreateIndexTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "create";
 
     protected async execute({ database, collection, keys }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const indexes = await provider.createIndexes(database, collection, [
             {
                 key: keys,

src/tools/mongodb/delete/deleteMany.ts

@@ -23,7 +23,7 @@ export class DeleteManyTool extends MongoDBToolBase {
         collection,
         filter,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.deleteMany(database, collection, filter);
 
         return {

src/tools/mongodb/delete/deleteOne.ts

@@ -23,7 +23,7 @@ export class DeleteOneTool extends MongoDBToolBase {
         collection,
         filter,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.deleteOne(database, collection, filter);
 
         return {

src/tools/mongodb/delete/dropCollection.ts

@@ -12,7 +12,7 @@ export class DropCollectionTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "delete";
 
     protected async execute({ database, collection }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.dropCollection(database, collection);
 
         return {

src/tools/mongodb/delete/dropDatabase.ts

@@ -11,7 +11,7 @@ export class DropDatabaseTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "delete";
 
     protected async execute({ database }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.dropDatabase(database);
 
         return {

src/tools/mongodb/metadata/collectionSchema.ts

@@ -11,7 +11,7 @@ export class CollectionSchemaTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute({ database, collection }: ToolArgs<typeof DbOperationArgs>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const documents = await provider.find(database, collection, {}, { limit: 5 }).toArray();
         const schema = await parseSchema(documents);
 

src/tools/mongodb/metadata/collectionStorageSize.ts

@@ -10,7 +10,7 @@ export class CollectionStorageSizeTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute({ database, collection }: ToolArgs<typeof DbOperationArgs>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const [{ value }] = await provider
             .aggregate(database, collection, [
                 { $collStats: { storageStats: {} } },

src/tools/mongodb/metadata/dbStats.ts

@@ -12,7 +12,7 @@ export class DbStatsTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute({ database }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.runCommandWithCheck(database, {
             dbStats: 1,
             scale: 1,

src/tools/mongodb/metadata/listCollections.ts

@@ -12,7 +12,7 @@ export class ListCollectionsTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute({ database }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const collections = await provider.listCollections(database);
 
         return {

src/tools/mongodb/metadata/listDatabases.ts

@@ -10,7 +10,7 @@ export class ListDatabasesTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute(): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const dbs = (await provider.listDatabases("")).databases as { name: string; sizeOnDisk: bson.Long }[];
 
         return {

src/tools/mongodb/mongodbTool.ts

@@ -4,6 +4,7 @@ import { State } from "../../state.js";
 import { NodeDriverServiceProvider } from "@mongosh/service-provider-node-driver";
 import { CallToolResult } from "@modelcontextprotocol/sdk/types.js";
 import { ErrorCodes, MongoDBError } from "../../errors.js";
+import config from "../../config.js";
 
 export const DbOperationArgs = {
     database: z.string().describe("Database name"),
@@ -19,8 +20,12 @@ export abstract class MongoDBToolBase extends ToolBase {
 
     protected abstract operationType: DbOperationType;
 
-    protected ensureConnected(): NodeDriverServiceProvider {
+    protected async ensureConnected(): Promise<NodeDriverServiceProvider> {
         const provider = this.state.serviceProvider;
+        if (!provider && config.connectionString) {
+            await this.connectToMongoDB(config.connectionString, this.state);
+        }
+
         if (!provider) {
             throw new MongoDBError(ErrorCodes.NotConnectedToMongoDB, "Not connected to MongoDB");
         }
@@ -46,4 +51,21 @@ export abstract class MongoDBToolBase extends ToolBase {
 
         return undefined;
     }
+
+    protected async connectToMongoDB(connectionString: string, state: State): Promise<void> {
+        const provider = await NodeDriverServiceProvider.connect(connectionString, {
+            productDocsLink: "https://docs.mongodb.com/todo-mcp",
+            productName: "MongoDB MCP",
+            readConcern: config.connectOptions.readConcern,
+            readPreference: config.connectOptions.readPreference,
+            writeConcern: {
+                w: config.connectOptions.writeConcern,
+            },
+            timeoutMS: config.connectOptions.timeoutMS,
+        });
+
+        state.serviceProvider = provider;
+        state.credentials.connectionString = connectionString;
+        await state.persistCredentials();
+    }
 }

src/tools/mongodb/read/aggregate.ts

@@ -19,7 +19,7 @@ export class AggregateTool extends MongoDBToolBase {
         collection,
         pipeline,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const documents = await provider.aggregate(database, collection, pipeline).toArray();
 
         const content: Array<{ text: string; type: "text" }> = [

src/tools/mongodb/read/count.ts

@@ -20,7 +20,7 @@ export class CountTool extends MongoDBToolBase {
     protected operationType: DbOperationType = "metadata";
 
     protected async execute({ database, collection, query }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const count = await provider.count(database, collection, query);
 
         return {

src/tools/mongodb/read/find.ts

@@ -38,7 +38,7 @@ export class FindTool extends MongoDBToolBase {
         limit,
         sort,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const documents = await provider.find(database, collection, filter, { projection, limit, sort }).toArray();
 
         const content: Array<{ text: string; type: "text" }> = [

src/tools/mongodb/update/renameCollection.ts

@@ -20,7 +20,7 @@ export class RenameCollectionTool extends MongoDBToolBase {
         newName,
         dropTarget,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.renameCollection(database, collection, newName, {
             dropTarget,
         });

src/tools/mongodb/update/updateMany.ts

@@ -35,7 +35,7 @@ export class UpdateManyTool extends MongoDBToolBase {
         update,
         upsert,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.updateMany(database, collection, filter, update, {
             upsert,
         });

src/tools/mongodb/update/updateOne.ts

@@ -35,7 +35,7 @@ export class UpdateOneTool extends MongoDBToolBase {
         update,
         upsert,
     }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
-        const provider = this.ensureConnected();
+        const provider = await this.ensureConnected();
         const result = await provider.updateOne(database, collection, filter, update, {
             upsert,
         });