Coercer Transform

The Vector coercer transform accepts and outputs log events, allowing you to coerce log fields into fixed types.

Configuration

• Common
• Advanced

vector.toml

[transforms.my_transform_id]
  # General
  type = "coercer" # required
  inputs = ["my-source-or-transform-id"] # required

  # Types
  types.status = "int" # example
  types.duration = "float" # example
  types.success = "bool" # example
  types.timestamp = "timestamp|%F" # example
  types.timestamp = "timestamp|%a %b %e %T %Y" # example
  types.parent.child = "int" # example

2 items

common

• booloptional

  drop_unspecified

  Set to true to drop all fields that are not specified in the types table. Make sure both message and timestamp are specified in the types table as their absense will cause the original message data to be dropped along with other extraneous fields.

  • Default: false
  • View examples
• tablecommonoptional

  types

  Key/value pairs representing mapped log field names and types. This is used to coerce log fields into their proper types.

  • stringenumcommonoptional

    [field-name]

    A definition of log field type conversions. They key is the log field name and the value is the type. strptime specifiers are supported for the timestamp type.

    • No default
    • Enum, must be one of: "bool" "float" "int" "string" "timestamp"
    • View examples

Examples

Given the following input:

{
  // ... existing fields
  "bytes_in": "5667",
  "bytes_out": "20574",
  "host": "5.86.210.12",
  "message": "GET /embrace/supply-chains/dynamic/vertical",
  "status": "201",
  "timestamp": "19/06/2019:17:20:49 -0400",
  "user_id": "zieme4647"
}

And the following configuration:

vector.toml

[transforms.<transform-id>]
  type = "coercer"

  types.bytes_in = "int"
  types.bytes_out = "int"
  types.timestamp = "timestamp|%d/%m/%Y:%H:%M:%S %z"
  types.status = "int"

A log event will be output with the following structure:

{
  // ... existing fields
  "bytes_in": 5667,
  "bytes_out": 20574,
  "host": "5.86.210.12",
  "message": "GET /embrace/supply-chains/dynamic/vertical",
  "status": 201,
  "timestamp": "2019-06-19T17:20:49-04:00",
  "user_id": "zieme4647"
}

How It Works

Complex Processing

If you encounter limitations with the coercer transform then we recommend using a runtime transform. These transforms are designed for complex processing and give you the power of full programming runtime.

Environment Variables

Environment variables are supported through all of Vector's configuration. Simply add ${MY_ENV_VAR} in your Vector configuration file and the variable will be replaced before being evaluated.

You can learn more in the Environment Variables section.

Value Coercion

Values can be coerced upon extraction via the types.* options. This functions exactly like the coercer transform except that its coupled within this transform for convenience.

Timestamps

You can coerce values into timestamps via the timestamp type:

vector.toml

# ...
types.first_timestamp = "timestamp" # best effort parsing
types.second_timestamp = "timestamp|%Y-%m-%dT%H:%M:%S%z" # ISO8601
# ...

As noted above, if you do not specify a specific strftime format, Vector will make a best effort attempt to parse the timestamp against the following common formats:

Format	Description
Without Timezone
%F %T	YYYY-MM-DD HH:MM:SS
%v %T	DD-Mmm-YYYY HH:MM:SS
FT%T	ISO 8601 / RFC 3339 without TZ
m/%d/%Y:%T	US common date format
a, %d %b %Y %T	RFC 822/2822 without TZ
a %d %b %T %Y	date command output without TZ
A %d %B %T %Y	date command output without TZ, long names
a %b %e %T %Y	ctime format
With Timezone
%+	ISO 8601 / RFC 3339
%a %d %b %T %Z %Y	date command output
%a %d %b %T %z %Y	date command output, numeric TZ
%a %d %b %T %#z %Y	date command output, numeric TZ
UTC Formats
%s	UNIX timestamp
%FT%TZ	ISO 8601 / RFC 3339 UTC