Influxdb2 write mode

src/timestream-for-influxdb-mcp-server/README.md

@@ -40,6 +40,7 @@ You can modify the settings of your MCP client to run your local server (e.g. fo
         "INFLUXDB_URL": "https://your-influxdb-endpoint:8086",
         "INFLUXDB_TOKEN": "your-influxdb-token",
         "INFLUXDB_ORG": "your-influxdb-org",
+        "INFLUXDB_WRITE_MODE": "false",
         "FASTMCP_LOG_LEVEL": "ERROR"
       },
       "disabled": false,
@@ -73,6 +74,7 @@ For Windows users, the MCP server configuration format is slightly different:
         "INFLUXDB_URL": "https://your-influxdb-endpoint:8086",
         "INFLUXDB_TOKEN": "your-influxdb-token",
         "INFLUXDB_ORG": "your-influxdb-org",
+        "INFLUXDB_WRITE_MODE": "false",
         "FASTMCP_LOG_LEVEL": "ERROR"
       }
     }
@@ -152,3 +154,32 @@ The Timestream for InfluxDB MCP server provides the following tools:
 ##### Organization Management
 - `InfluxDBListOrgs`: List all organizations in InfluxDB
 - `InfluxDBCreateOrg`: Create a new organization in InfluxDB
+
+## Configuration
+
+### Environment Variables
+
+| Variable | Required | Default | Description |
+|----------|----------|---------|-------------|
+| `AWS_PROFILE` | No | — | AWS profile for control-plane operations |
+| `AWS_REGION` | No | `us-east-1` | AWS region |
+| `INFLUXDB_URL` | No | — | InfluxDB v2 endpoint URL (e.g. `https://host:8086`) |
+| `INFLUXDB_TOKEN` | No | — | InfluxDB v2 authentication token |
+| `INFLUXDB_ORG` | No | — | InfluxDB v2 organization name |
+| `INFLUXDB_ALLOWED_URLS` | No | — | Comma-separated list of additional approved InfluxDB URLs |
+| `INFLUXDB_WRITE_MODE` | No | `false` | Enable write-producing Flux operations in queries (see below) |
+| `FASTMCP_LOG_LEVEL` | No | — | Logging level (`ERROR`, `WARNING`, `INFO`, `DEBUG`) |
+
+### Write Mode
+
+By default, the `InfluxDBQuery` tool rejects Flux queries that contain write-producing operations such as `to()`, `experimental.to()`, and `wideTo()`. This ensures that the query tool behaves as read-only, even when the configured InfluxDB token has write permissions.
+
+To enable write-producing Flux operations through the query tool, set:
+
+```
+INFLUXDB_WRITE_MODE=true
+```
+
+This setting is operator-controlled and cannot be overridden by tool callers.
+
+> **Best practice:** For deployments that need both read and write capabilities, configure a **read-only InfluxDB token** for general use and enable the explicit write tools (`InfluxDBWritePoints`, `InfluxDBWriteLP`) with `tool_write_mode=True` only when needed. This provides the strongest data integrity guarantee regardless of the MCP server's write-mode setting.

src/timestream-for-influxdb-mcp-server/awslabs/timestream_for_influxdb_mcp_server/server.py

@@ -17,6 +17,7 @@
 
 import boto3
 import os
+import re
 from awslabs.timestream_for_influxdb_mcp_server import __version__
 from botocore.config import Config
 from influxdb_client.client.influxdb_client import InfluxDBClient
@@ -40,6 +41,7 @@
 INFLUXDB_URL = os.environ.get('INFLUXDB_URL')
 INFLUXDB_ORG = os.environ.get('INFLUXDB_ORG')
 INFLUXDB_ALLOWED_URLS = os.environ.get('INFLUXDB_ALLOWED_URLS', '')
+INFLUXDB_WRITE_MODE = os.environ.get('INFLUXDB_WRITE_MODE', 'false').lower() == 'true'
 
 # Define Field parameters as global variables to avoid duplication
 # Common fields
@@ -437,6 +439,63 @@ def get_influxdb_client(url, token, org=None, timeout=10000, verify_ssl: bool =
     )
 
 
+def validate_flux_query(query: str) -> None:
+    """Validate that a Flux query does not contain write-producing operations.
+
+    When INFLUXDB_WRITE_MODE is disabled (default), this function rejects Flux
+    queries that contain functions capable of writing data to InfluxDB. This
+    provides defense-in-depth protection against data modification through
+    the query interface.
+
+    The following write-producing Flux functions are blocked:
+    - to() — standard write function (influxdata/influxdb/to)
+    - experimental.to() — experimental write function
+    - wideTo() / influxdb.wideTo() — writes wide/pivoted data
+
+    Args:
+        query: The Flux query string to validate.
+
+    Raises:
+        ValueError: If the query contains write-producing operations and
+            INFLUXDB_WRITE_MODE is not enabled.
+    """
+    if INFLUXDB_WRITE_MODE:
+        return
+
+    # Strip single-line comments (// ...) to avoid false positives from commented-out code.
+    # Preserve line structure so that multi-line patterns still work.
+    stripped = re.sub(r'//[^\n]*', '', query)
+
+    # Patterns to detect write-producing Flux functions.
+    # These cover:
+    #   - Pipe-forward to `to(` — e.g. `|> to(bucket: "x")`
+    #   - Standalone or qualified calls — e.g. `to(bucket: "x")`,
+    #     `experimental.to(`, `influxdb.wideTo(`
+    #   - Aliased imports — e.g. `import ex "experimental"` then `ex.to(`
+    # The word-boundary and parenthesis requirements minimize false positives
+    # from identifiers like `toString` or field names containing "to".
+    write_patterns = [
+        # Pipe-forward into to(): |> to(
+        r'\|>\s*to\s*\(',
+        # Qualified calls: experimental.to( or <alias>.to( preceded by word char + dot
+        r'\w+\.to\s*\(',
+        # wideTo as standalone or qualified: wideTo( or <qualifier>.wideTo(
+        r'(?:\w+\.)?wideTo\s*\(',
+        # Standalone to() at statement level — preceded by start-of-line or semicolon
+        # but NOT preceded by a dot (which would be a method on something else).
+        r'(?:^|;\s*)to\s*\(',
+    ]
+
+    for pattern in write_patterns:
+        if re.search(pattern, stripped, re.MULTILINE):
+            raise ValueError(
+                'Query contains a write-producing Flux operation (to(), experimental.to(), '
+                'or wideTo()) which is not allowed when INFLUXDB_WRITE_MODE is not enabled. '
+                'Set the INFLUXDB_WRITE_MODE=true environment variable to allow write '
+                'operations through Flux queries.'
+            )
+
+
 @mcp.tool(
     name='CreateDbCluster', description='Create a new Timestream for InfluxDB database cluster.'
 )
@@ -1365,6 +1424,9 @@ async def influxdb_query(
     Returns:
         Query results in the specified format.
     """
+    # Validate query does not contain write-producing operations in read-only mode
+    validate_flux_query(query)
+
     resolved_url, resolved_token, resolved_org = resolve_influxdb_config(url, token, org)
 
     try: