File Descriptor

Collect logs from a file descriptor

status: stable role: sidecar delivery: at-least-once acknowledgements: no egress: stream state: stateless output: log
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Configuration

Example configurations 

{
  "sources": {
    "my_source_id": {
      "type": "file_descriptor",
      "fd": 10
    }
  }
}
[sources.my_source_id]
type = "file_descriptor"
fd = 10

sources:
  my_source_id:
    type: file_descriptor
    fd: 10

{
  "sources": {
    "my_source_id": {
      "type": "file_descriptor",
      "fd": 10,
      "max_length": 102400
    }
  }
}
[sources.my_source_id]
type = "file_descriptor"
fd = 10
max_length = 102_400

sources:
  my_source_id:
    type: file_descriptor
    fd: 10
    max_length: 102400

decoding

optional object
Configures how events are decoded from raw bytes.

decoding.avro

required object
Apache Avro-specific encoder options.
Relevant when: codec = "avro"
decoding.avro.schema
required string literal

The Avro schema definition. Please note that the following [apache_avro::types::Value] variants are currently not supported:

  • Date
  • Decimal
  • Duration
  • Fixed
  • TimeMillis
Examples 
"{ \"type\": \"record\", \"name\": \"log\", \"fields\": [{ \"name\": \"message\", \"type\": \"string\" }] }"
decoding.avro.strip_schema_id_prefix
required bool
For Avro datum encoded in Kafka messages, the bytes are prefixed with the schema ID. Set this to true to strip the schema ID prefix. According to Confluent Kafka’s document.

decoding.codec

optional string literal enum
The codec to use for decoding events.
Enum options
OptionDescription
avroDecodes the raw bytes as as an Apache Avro message.
bytesUses the raw bytes as-is.
gelf

Decodes the raw bytes as a GELF message.

This codec is experimental for the following reason:

The GELF specification is more strict than the actual Graylog receiver. Vector’s decoder currently adheres more strictly to the GELF spec, with the exception that some characters such as @ are allowed in field names.

Other GELF codecs such as Loki’s, use a Go SDK that is maintained by Graylog, and is much more relaxed than the GELF spec.

Going forward, Vector will use that Go SDK as the reference implementation, which means the codec may continue to relax the enforcement of specification.

influxdbDecodes the raw bytes as an Influxdb Line Protocol message.
jsonDecodes the raw bytes as JSON.
native

Decodes the raw bytes as native Protocol Buffers format.

This codec is experimental.

native_json

Decodes the raw bytes as native JSON format.

This codec is experimental.

protobufDecodes the raw bytes as protobuf.
syslog

Decodes the raw bytes as a Syslog message.

Decodes either as the RFC 3164-style format (“old” style) or the RFC 5424-style format (“new” style, includes structured data).

vrlDecodes the raw bytes as a string and passes them as input to a VRL program.
default: bytes

decoding.gelf

optional object
GELF-specific decoding options.
Relevant when: codec = "gelf"
decoding.gelf.lossy
optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.influxdb

optional object
Influxdb-specific decoding options.
Relevant when: codec = "influxdb"
decoding.influxdb.lossy
optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.json

optional object
JSON-specific decoding options.
Relevant when: codec = "json"
decoding.json.lossy
optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.native_json

optional object
Vector’s native JSON-specific decoding options.
Relevant when: codec = "native_json"
decoding.native_json.lossy
optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.protobuf

optional object
Protobuf-specific decoding options.
Relevant when: codec = "protobuf"
decoding.protobuf.desc_file
optional string literal
Path to desc file
decoding.protobuf.message_type
optional string literal
message type. e.g package.message

decoding.syslog

optional object
Syslog-specific decoding options.
Relevant when: codec = "syslog"
decoding.syslog.lossy
optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.vrl

required object
VRL-specific decoding options.
Relevant when: codec = "vrl"
decoding.vrl.source
required string literal
The Vector Remap Language (VRL) program to execute for each event. Note that the final contents of the . target will be used as the decoding result. Compilation error or use of ‘abort’ in a program will result in a decoding error.
decoding.vrl.timezone
optional string literal

The name of the timezone to apply to timestamp conversions that do not contain an explicit time zone. The time zone name may be any name in the TZ database, or local to indicate system local time.

If not set, local will be used.

Examples 
"local"
"America/New_York"
"EST5EDT"

fd

required uint
The file descriptor number to read from.
Examples 
10

framing

optional object

Framing configuration.

Framing handles how events are separated when encoded in a raw byte form, where each event is a frame that must be prefixed, or delimited, in a way that marks where an event begins and ends within the byte stream.

framing.character_delimited

required object
Options for the character delimited decoder.
Relevant when: method = "character_delimited"
framing.character_delimited.delimiter
required ascii_char
The character that delimits byte sequences.
framing.character_delimited.max_length
optional uint

The maximum length of the byte buffer.

This length does not include the trailing delimiter.

By default, there is no maximum length enforced. If events are malformed, this can lead to additional resource usage as events continue to be buffered in memory, and can potentially lead to memory exhaustion in extreme cases.

If there is a risk of processing malformed data, such as logs with user-controlled input, consider setting the maximum length to a reasonably large value as a safety net. This ensures that processing is not actually unbounded.

framing.chunked_gelf

optional object
Options for the chunked GELF decoder.
Relevant when: method = "chunked_gelf"
framing.chunked_gelf.decompression
optional string literal enum
Decompression configuration for GELF messages.
Enum options
OptionDescription
AutoAutomatically detect the decompression method based on the magic bytes of the message.
GzipUse Gzip decompression.
NoneDo not decompress the message.
ZlibUse Zlib decompression.
default: Auto
framing.chunked_gelf.max_length
optional uint

The maximum length of a single GELF message, in bytes. Messages longer than this length will be dropped. If this option is not set, the decoder does not limit the length of messages and the per-message memory is unbounded.

Note that a message can be composed of multiple chunks and this limit is applied to the whole message, not to individual chunks.

This limit takes only into account the message’s payload and the GELF header bytes are excluded from the calculation. The message’s payload is the concatenation of all the chunks’ payloads.

framing.chunked_gelf.pending_messages_limit
optional uint
The maximum number of pending incomplete messages. If this limit is reached, the decoder starts dropping chunks of new messages, ensuring the memory usage of the decoder’s state is bounded. If this option is not set, the decoder does not limit the number of pending messages and the memory usage of its messages buffer can grow unbounded. This matches Graylog Server’s behavior.
framing.chunked_gelf.timeout_secs
optional float
The timeout, in seconds, for a message to be fully received. If the timeout is reached, the decoder drops all the received chunks of the timed out message.
default: 5

framing.length_delimited

required object
Options for the length delimited decoder.
Relevant when: method = "length_delimited"
framing.length_delimited.length_field_is_big_endian
optional bool
Length field byte order (little or big endian)
default: true
framing.length_delimited.length_field_length
optional uint
Number of bytes representing the field length
default: 4
framing.length_delimited.length_field_offset
optional uint
Number of bytes in the header before the length field
framing.length_delimited.max_frame_length
optional uint
Maximum frame length
default: 8.388608e+06

framing.method

required string literal enum
The framing method.
Enum options
OptionDescription
bytesByte frames are passed through as-is according to the underlying I/O boundaries (for example, split between messages or stream segments).
character_delimitedByte frames which are delimited by a chosen character.
chunked_gelfByte frames which are chunked GELF messages.
length_delimitedByte frames which are prefixed by an unsigned big-endian 32-bit integer indicating the length.
newline_delimitedByte frames which are delimited by a newline character.
octet_countingByte frames according to the octet counting format.
Examples 
"bytes"
"character_delimited"
"chunked_gelf"
"length_delimited"
"newline_delimited"
"octet_counting"

framing.newline_delimited

optional object
Options for the newline delimited decoder.
Relevant when: method = "newline_delimited"
framing.newline_delimited.max_length
optional uint

The maximum length of the byte buffer.

This length does not include the trailing delimiter.

By default, there is no maximum length enforced. If events are malformed, this can lead to additional resource usage as events continue to be buffered in memory, and can potentially lead to memory exhaustion in extreme cases.

If there is a risk of processing malformed data, such as logs with user-controlled input, consider setting the maximum length to a reasonably large value as a safety net. This ensures that processing is not actually unbounded.

framing.octet_counting

optional object
Options for the octet counting decoder.
Relevant when: method = "octet_counting"
framing.octet_counting.max_length
optional uint
The maximum length of the byte buffer.

host_key

optional string literal

Overrides the name of the log field used to add the current hostname to each event.

By default, the global host_key option is used.

max_length

optional uint

The maximum buffer size, in bytes, of incoming messages.

Messages larger than this are truncated.

default: 102400 (bytes)

Outputs

<component_id>

Default output stream of the component. Use this component’s ID as an input to downstream transforms and sinks.

Output Data

Logs

Warning

The fields shown below will be different if log namespacing is enabled. See Log Namespacing for more details

Line

An individual event from the file descriptor.
Fields
host required string literal
The local hostname, equivalent to the gethostname command.
Examples
my-host.local
message required string literal
The raw line, unparsed.
Examples
2019-02-13T19:48:34+00:00 [info] Started GET "/" for 127.0.0.1
timestamp required timestamp
The exact time the event was ingested into Vector.
Examples
2020-10-10T17:07:36.452332Z

Telemetry

Metrics

link

component_discarded_events_total

counter
The number of events dropped by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
intentional
True if the events were discarded intentionally, like a filter transform, or false if due to an error.
pid optional
The process ID of the Vector instance.

component_errors_total

counter
The total number of errors encountered by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
error_type
The type of the error
host optional
The hostname of the system Vector is running on.
pid optional
The process ID of the Vector instance.
stage
The stage within the component at which the error occurred.

component_received_bytes_total

counter
The number of raw bytes accepted by this component from source origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_event_bytes_total

counter
The number of event bytes accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_events_count

histogram

A histogram of the number of events passed in each internal batch in Vector’s internal topology.

Note that this is separate than sink-level batching. It is mostly useful for low level debugging performance issues in Vector due to small internal batches.

component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_events_total

counter
The number of events accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_sent_event_bytes_total

counter
The total number of event bytes emitted by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
output optional
The specific output of the component.
pid optional
The process ID of the Vector instance.

component_sent_events_total

counter
The total number of events emitted by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
output optional
The specific output of the component.
pid optional
The process ID of the Vector instance.

source_lag_time_seconds

histogram
The difference between the timestamp recorded in each event and the time when it was ingested, expressed as fractional seconds.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
pid optional
The process ID of the Vector instance.

Examples

Line sent over pipe

Given this event...
2019-02-13T19:48:34+00:00 [info] Started GET "/" for 127.0.0.1
...and this configuration...
sources:
  my_source_id:
    type: file_descriptor
    fd: 10

[sources.my_source_id]
type = "file_descriptor"
fd = 10

{
  "sources": {
    "my_source_id": {
      "type": "file_descriptor",
      "fd": 10
    }
  }
}
...this Vector event is produced:
{
  "host": "my-host.local",
  "message": "2019-02-13T19:48:34+00:00 [info] Started GET \"/\" for 127.0.0.1",
  "timestamp": "2020-10-10T17:07:36.452332Z"
}

How it works

Context

By default, the file_descriptor source augments events with helpful context keys.

Line Delimiters

Each line is read until a new line delimiter, the 0xA byte, is found.

State

This component is stateless, meaning its behavior is consistent across each input.
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