influxdata/influxdb · error · InvalidKeyError

key ' ' cannot contain commas

Error message

{key_type} key '{key}' cannot contain commas

What it means

LineBuilder._validate_key rejects tag/field keys containing a comma, since commas separate tags in line protocol and a raw comma in a key would break point parsing. InvalidKeyError names the offending key and key_type when a comma is present.

Solutions

1. Strip or replace commas in keys before passing them to LineBuilder (key = key.replace(',', '')).
2. Properly split comma-separated key lists and add each key individually.
3. Sanitize dynamic/external keys with a regex removing line-protocol delimiters (, = and spaces).

Example fix

# before
lb.tag(raw_key, value)
# after
lb.tag(raw_key.replace(',', '_'), value)

import re
def sanitize_key(key: str) -> str:
    return re.sub(r"[, =]", "_", key.strip())

# then: lb.tag(sanitize_key(k), v)

def has_no_commas(k) -> bool:
    return isinstance(k, str) and "," not in k

try:
    lb.tag(key, value)
except InvalidKeyError:
    lb.tag(re.sub(r"[, =]", "_", key), value)

When it happens

Trigger: Calling lb.tag("a,b", "v") or any field setter with a key containing ',' — typically keys parsed from comma-separated input where the split was not performed, or raw sensor/channel identifiers embedding commas.

Common situations: Passing 'tag1,tag2' strings as a single key; metric names from systems that use comma-separated lists; unnormalized user input.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• key cannot be empty
• key ' ' cannot contain spaces
• Measurement name cannot contain spaces
• At least one field is required
• key ' ' cannot contain equals signs

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/2e7c9798a1f3754b. Report an issue: GitHub.

Appendix: source

Thrown at influxdb3_py_api/src/line_builder/line_builder.py:45

class LineBuilder:
    def __init__(self, measurement: str):
        if " " in measurement:
            raise InvalidMeasurementError("Measurement name cannot contain spaces")
        self.measurement = measurement
        self.tags: OrderedDict[str, str] = OrderedDict()
        self.fields: OrderedDict[str, str] = OrderedDict()
        self._timestamp_ns: Optional[int] = None

    def _validate_key(self, key: str, key_type: str) -> None:
        """Validate that a key does not contain spaces, commas, or equals signs."""
        if not key:
            raise InvalidKeyError(f"{key_type} key cannot be empty")
        if " " in key:
            raise InvalidKeyError(f"{key_type} key '{key}' cannot contain spaces")
        if "," in key:
            raise InvalidKeyError(f"{key_type} key '{key}' cannot contain commas")
        if "=" in key:
            raise InvalidKeyError(f"{key_type} key '{key}' cannot contain equals signs")

    def _escape_measurement(self, value: str) -> str:
        """Escape characters in measurement names according to line protocol."""
        return value.replace(",", "\\,").replace(" ", "\\ ")

    def _escape_tag_value(self, value: str) -> str:
        """Escape characters in tag values according to line protocol."""
        return (
            value.replace("\\", "\\\\")
            .replace(",", "\\,")
            .replace("=", "\\=")
            .replace(" ", "\\ ")
        )

    def _escape_field_key(self, value: str) -> str:
        """Escape characters in field keys according to line protocol."""

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