AWS Cloudwatch logs

Publish log events to AWS Cloudwatch Logs

status: stable delivery: at-least-once egress: batch state: stateless

Configuration

Example configurations

{
  "sinks": {
    "my_sink_id": {
      "type": "aws_cloudwatch_logs",
      "inputs": "my-source-or-transform-id",
      "create_missing_group": true,
      "create_missing_stream": true,
      "group_name": "group-name",
      "compression": "none",
      "region": "us-east-1",
      "stream_name": "{{ host }}"
    }
  }
}
[sinks.my_sink_id]
type = "aws_cloudwatch_logs"
inputs = "my-source-or-transform-id"
create_missing_group = true
create_missing_stream = true
group_name = "group-name"
compression = "none"
region = "us-east-1"
stream_name = "{{ host }}"
---
sinks:
  my_sink_id:
    type: aws_cloudwatch_logs
    inputs: my-source-or-transform-id
    create_missing_group: true
    create_missing_stream: true
    group_name: group-name
    compression: none
    encoding: null
    healthcheck: null
    region: us-east-1
    stream_name: "{{ host }}"
{
  "sinks": {
    "my_sink_id": {
      "type": "aws_cloudwatch_logs",
      "inputs": "my-source-or-transform-id",
      "endpoint": "127.0.0.0:5000/path/to/service",
      "create_missing_group": true,
      "create_missing_stream": true,
      "group_name": "group-name",
      "compression": "none",
      "region": "us-east-1",
      "stream_name": "{{ host }}"
    }
  }
}
[sinks.my_sink_id]
type = "aws_cloudwatch_logs"
inputs = "my-source-or-transform-id"
endpoint = "127.0.0.0:5000/path/to/service"
create_missing_group = true
create_missing_stream = true
group_name = "group-name"
compression = "none"
region = "us-east-1"
stream_name = "{{ host }}"
---
sinks:
  my_sink_id:
    type: aws_cloudwatch_logs
    inputs: my-source-or-transform-id
    auth: null
    endpoint: 127.0.0.0:5000/path/to/service
    create_missing_group: true
    create_missing_stream: true
    group_name: group-name
    buffer: null
    batch: null
    compression: none
    encoding: null
    healthcheck: null
    request: null
    region: us-east-1
    stream_name: "{{ host }}"

auth

optional object
Options for the authentication strategy.

auth.access_key_id

optional string literal
The AWS access key id. Used for AWS authentication when communicating with AWS services.

auth.assume_role

optional string literal
The ARN of an IAM role to assume at startup.

auth.secret_access_key

optional string literal
The AWS secret access key. Used for AWS authentication when communicating with AWS services.

batch

optional object
Configures the sink batching behavior.

batch.max_bytes

optional uint
The maximum size of a batch, in bytes, before it is flushed.
default: 1.048576e+06 (bytes)

batch.max_events

optional uint
The maximum size of a batch, in events, before it is flushed.
default: 10000 (events)

batch.timeout_secs

optional uint
The maximum age of a batch before it is flushed.
default: 1 (seconds)

buffer

optional object
Configures the sink specific buffer behavior.

buffer.max_events

optional uint
The maximum number of events allowed in the buffer.
Relevant when: type = "memory"
default: 500 (events)

buffer.max_size

required uint
The maximum size of the buffer on the disk.
Relevant when: type = "disk"

buffer.type

optional string enum literal
The buffer’s type and storage mechanism.
Enum options
OptionDescription
diskStores the sink’s buffer on disk. This is less performant, but durable. Data will not be lost between restarts. Will also hold data in memory to enhance performance. WARNING: This may stall the sink if disk performance isn’t on par with the throughput. For comparison, AWS gp2 volumes are usually too slow for common cases.
memoryStores the sink’s buffer in memory. This is more performant, but less durable. Data will be lost if Vector is restarted forcefully.
default: memory

buffer.when_full

optional string enum literal
The behavior when the buffer becomes full.
Enum options
OptionDescription
blockApplies back pressure when the buffer is full. This prevents data loss, but will cause data to pile up on the edge.
drop_newestDrops new data as it’s received. This data is lost. This should be used when performance is the highest priority.
default: block

compression

common optional string enum

The compression strategy used to compress the encoded event data before transmission.

Some cloud storage API clients and browsers will handle decompression transparently, so files may not always appear to be compressed depending how they are accessed.

Enum options string literal
OptionDescription
gzipGzip standard DEFLATE compression.
noneNo compression.
syntaxliteral
default: none

create_missing_group

common optional bool
Dynamically create a log group if it does not already exist. This will ignore create_missing_stream directly after creating the group and will create the first stream.
default: true

create_missing_stream

common optional bool
Dynamically create a log stream if it does not already exist.
default: true

encoding

required object
Configures the encoding specific sink behavior.

encoding.codec

required string literal
The encoding codec used to serialize the events before outputting.

encoding.except_fields

optional array
Prevent the sink from encoding the specified fields.

encoding.only_fields

optional array
Makes the sink encode only the specified fields.

encoding.timestamp_format

optional string enum literal
How to format event timestamps.
Enum options
OptionDescription
rfc3339Formats as a RFC3339 string
unixFormats as a unix timestamp
default: rfc3339

endpoint

optional string
Custom endpoint for use with AWS-compatible services. Providing a value for this option will make region moot.

group_name

required string
The group name of the target CloudWatch Logs stream.

healthcheck

common optional object
Health check options for the sink.

healthcheck.enabled

optional bool
Enables/disables the healthcheck upon Vector boot.
default: true

inputs

required [string]

A list of upstream source or transform IDs. Wildcards (*) are supported but must be the last character in the ID.

See configuration for more info.

Array string literal
Examples
[
  "my-source-or-transform-id",
  "prefix-*"
]

region

required string
The AWS region of the target service. If endpoint is provided it will override this value since the endpoint includes the region.

request

optional object
Configures the sink request behavior.

request.adaptive_concurrency

optional object
Configure the adaptive concurrency algorithms. These values have been tuned by optimizing simulated results. In general you should not need to adjust these.

request.concurrency

optional uint
The maximum number of in-flight requests allowed at any given time.
default: 5 (requests)

request.rate_limit_duration_secs

optional uint
The time window, in seconds, used for the rate_limit_num option.
default: 1 (seconds)

request.rate_limit_num

optional uint
The maximum number of requests allowed within the rate_limit_duration_secs time window.
default: 5

request.retry_attempts

optional uint
The maximum number of retries to make for failed requests. The default, for all intents and purposes, represents an infinite number of retries.
default: 1.8446744073709552e+19

request.retry_initial_backoff_secs

optional uint
The amount of time to wait before attempting the first retry for a failed request. Once, the first retry has failed the fibonacci sequence will be used to select future backoffs.
default: 1 (seconds)

request.retry_max_duration_secs

optional uint
The maximum amount of time, in seconds, to wait between retries.
default: 10 (seconds)

request.timeout_secs

optional uint
The maximum time a request can take before being aborted. It is highly recommended that you do not lower this value below the service’s internal timeout, as this could create orphaned requests, pile on retries, and result in duplicate data downstream.
default: 30 (seconds)

stream_name

required string
The stream name of the target CloudWatch Logs stream. Note that there can only be one writer to a log stream at a time so if you are running multiple vectors all writing to the same log group, include a identifier in the stream name that is guaranteed to be unique by vector instance (for example, you might choose host)

Environment variables

AWS_ACCESS_KEY_ID

common optional string literal
The AWS access key id. Used for AWS authentication when communicating with AWS services.
Examples
AKIAIOSFODNN7EXAMPLE

AWS_CONFIG_FILE

common optional string literal
Specifies the location of the file that the AWS CLI uses to store configuration profiles.
Default: ~/.aws/config

AWS_CREDENTIAL_EXPIRATION

common optional string literal
Expiration time in RFC 3339 format. If unset, credentials won’t expire.
Examples
1996-12-19T16:39:57-08:00

AWS_DEFAULT_REGION

common optional string literal
The default AWS region.
Examples
/path/to/credentials.json

AWS_PROFILE

common optional string literal
Specifies the name of the CLI profile with the credentials and options to use. This can be the name of a profile stored in a credentials or config file.
Default: default
Examples
my-custom-profile

AWS_ROLE_SESSION_NAME

common optional string literal
Specifies a name to associate with the role session. This value appears in CloudTrail logs for commands performed by the user of this profile.
Examples
vector-session

AWS_SECRET_ACCESS_KEY

common optional string literal
The AWS secret access key. Used for AWS authentication when communicating with AWS services.
Examples
wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

AWS_SESSION_TOKEN

common optional string literal
The AWS session token. Used for AWS authentication when communicating with AWS services.
Examples
AQoEXAMPLEH4aoAH0gNCAPy...truncated...zrkuWJOgQs8IZZaIv2BXIa2R4Olgk

AWS_SHARED_CREDENTIALS_FILE

common optional string literal
Specifies the location of the file that the AWS CLI uses to store access keys.
Default: ~/.aws/credentials

Telemetry

Metrics

link

events_discarded_total

counter
The total number of events discarded by this component.

events_in_total

counter
The number of events accepted by this component either from tagged origin like file and uri, or cumulatively from other origins.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.
container_name optional
The name of the container from which the event originates.
file optional
The file from which the event originates.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the event originates.
peer_path optional
The pathname from which the event originates.
pod_name optional
The name of the pod from which the event originates.
uri optional
The sanitized URI from which the event originates.

events_out_total

counter
The total number of events emitted by this component.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.

processing_errors_total

counter
The total number of processing errors encountered by this component.
component_kind required
The Vector component kind.
component_name required
The Vector component name.
component_type required
The Vector component type.
error_type required
The type of the error

Permissions

How it works

AWS authentication

Vector checks for AWS credentials in the following order:

  1. The access_key_id and secret_access_key options.
  2. The AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.
  3. The credential_process command in the AWS config file (usually located at ~/.aws/config).
  4. The AWS credentials file (usually located at ~/.aws/credentials).
  5. The IAM instance profile (only works if running on an EC2 instance with an instance profile/role).

If no credentials are found, Vector’s health check fails and an error is logged. If your AWS credentials expire, Vector will automatically search for up-to-date credentials in the places (and order) described above.

Obtaining an access key

In general, we recommend using instance profiles/roles whenever possible. In cases where this is not possible you can generate an AWS access key for any user within your AWS account. AWS provides a detailed guide on how to do this. Such created AWS access keys can be used via access_key_id and secret_access_key options.

Assuming roles

Vector can assume an AWS IAM role via the assume_role option. This is an optional setting that is helpful for a variety of use cases, such as cross account access.

Buffers and batches

This component buffers & batches data as shown in the diagram above. You’ll notice that Vector treats these concepts differently, instead of treating them as global concepts, Vector treats them as sink specific concepts. This isolates sinks, ensuring services disruptions are contained and delivery guarantees are honored.

Batches are flushed when 1 of 2 conditions are met:

  1. The batch age meets or exceeds the configured timeout_secs.
  2. The batch size meets or exceeds the configured max_size or max_events.

Buffers are controlled via the buffer.* options.

Health checks

Health checks ensure that the downstream service is accessible and ready to accept data. This check is performed upon sink initialization. If the health check fails an error will be logged and Vector will proceed to start.

Require health checks

If you’d like to exit immediately upon a health check failure, you can pass the --require-healthy flag:

vector --config /etc/vector/vector.toml --require-healthy

Disable health checks

If you’d like to disable health checks for this sink you can set the healthcheck option to false.

Partitioning

Vector supports dynamic configuration values through a simple template syntax. If an option supports templating, it will be noted with a badge and you can use event fields to create dynamic values. For example:

[sinks.my-sink]
dynamic_option = "application={{ application_id }}"

In the above example, the application_id for each event will be used to partition outgoing data.

Rate limits & adapative concurrency

Adaptive Request Concurrency (ARC)

Adaptive Requst Concurrency is a feature of Vector that does away with static rate limits and automatically optimizes HTTP concurrency limits based on downstream service responses. The underlying mechanism is a feedback loop inspired by TCP congestion control algorithms. Checkout the announcement blog post,

We highly recommend enabling this feature as it improves performance and reliability of Vector and the systems it communicates with.

To enable, set the request.concurrency option to adaptive:

[sinks.my-sink]
  request.concurrency = "adaptive"

Static rate limits

If Adaptive Request Concurrency is not for you, you can manually set static rate limits with the request.rate_limit_duration_secs, request.rate_limit_num, and request.concurrency options:

[sinks.my-sink]
  request.rate_limit_duration_secs = 1
  request.rate_limit_num = 10
  request.concurrency = 10

Retry policy

Vector will retry failed requests (status == 429, >= 500, and != 501). Other responses will not be retried. You can control the number of retry attempts and backoff rate with the request.retry_attempts and request.retry_backoff_secs options.

State

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