AWS Lambda¶
This filter should be configured with the name envoy.filters.http.aws_lambda.
Attention
The AWS Lambda filter is currently under active development.
The HTTP AWS Lambda filter is used to trigger an AWS Lambda function from a standard HTTP request. It supports a few options to control whether to pass through the HTTP request payload as is or to wrap it in a JSON schema.
If payload_passthrough is set to
true
, then the payload is sent to Lambda without any transformations.
Note: This means you lose access to all the HTTP headers in the Lambda function.
However, if payload_passthrough
is set to false
, then the HTTP request is transformed to a JSON payload with the following schema:
{
"rawPath": "/path/to/resource",
"method": "GET|POST|HEAD|...",
"headers": {"header-key": "header-value", ... },
"queryStringParameters": {"key": "value", ...},
"body": "...",
"isBase64Encoded": true|false
}
rawPath
is the HTTP request resource path (including the query string)method
is the HTTP request method. For exampleGET
,PUT
, etc.headers
are the HTTP request headers. If multiple headers share the same name, their values are coalesced into a single comma-separated value.queryStringParameters
are the HTTP request query string parameters. If multiple parameters share the same name, the last one wins. That is, parameters are _not_ coalesced into a single value if they share the same key name.body
the body of the HTTP request is base64-encoded by the filter if thecontent-type
header exists and is _not_ one of the following:text/*
application/json
application/xml
application/javascript
Otherwise, the body of HTTP request is added to the JSON payload as is.
On the other end, the response of the Lambda function must conform to the following schema:
{
"statusCode": ...
"headers": {"header-key": "header-value", ... },
"cookies": ["key1=value1; HttpOnly; ...", "key2=value2; Secure; ...", ...],
"body": "...",
"isBase64Encoded": true|false
}
The
statusCode
field is an integer used as the HTTP response code. If this key is missing, Envoy returns a200 OK
.The
headers
are used as the HTTP response headers.The
cookies
are used asSet-Cookie
response headers. Unlike the request headers, cookies are _not_ part of the response headers because theSet-Cookie
header cannot contain more than one value per the RFC. Therefore, Each key/value pair in this JSON array will translate to a singleSet-Cookie
header.The
body
is base64-decoded if it is marked as base64-encoded and sent as the body of the HTTP response.
Note
The target cluster must have its endpoint set to the regional Lambda endpoint. Use the same region as the Lambda function.
AWS IAM credentials must be defined in either environment variables, EC2 metadata or ECS task metadata.
The filter supports per-filter configuration.
If you use the per-filter configuration, the target cluster _must_ have the following metadata:
metadata:
filter_metadata:
com.amazonaws.lambda:
egress_gateway: true
Below are some examples that show how the filter can be used in different deployment scenarios.
Example configuration¶
In this configuration, the filter applies to all routes in the filter chain of the http connection manager:
http_filters:
- name: envoy.filters.http.aws_lambda
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.http.aws_lambda.v3.Config
arn: "arn:aws:lambda:us-west-2:987654321:function:hello_envoy"
payload_passthrough: true
The corresponding regional endpoint must be specified in the target cluster. So, for example if the Lambda function is in us-west-2:
clusters:
- name: lambda_egress_gateway
connect_timeout: 0.25s
type: LOGICAL_DNS
dns_lookup_family: V4_ONLY
lb_policy: ROUND_ROBIN
load_assignment:
cluster_name: lambda_egress_gateway
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: lambda.us-west-2.amazonaws.com
port_value: 443
transport_socket:
name: envoy.transport_sockets.tls
typed_config:
"@type": type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.UpstreamTlsContext
sni: "*.amazonaws.com"
The filter can also be configured per virtual-host, route or weighted-cluster. In that case, the target cluster must have specific Lambda metadata.
weighted_clusters:
clusters:
- name: lambda_egress_gateway
weight: 42
typed_per_filter_config:
envoy.filters.http.aws_lambda:
"@type": type.googleapis.com/envoy.extensions.filters.http.aws_lambda.v3.PerRouteConfig
invoke_config:
arn: "arn:aws:lambda:us-west-2:987654321:function:hello_envoy"
payload_passthrough: false
An example with the Lambda metadata applied to a weighted-cluster:
clusters:
- name: lambda_egress_gateway
connect_timeout: 0.25s
type: LOGICAL_DNS
dns_lookup_family: V4_ONLY
lb_policy: ROUND_ROBIN
metadata:
filter_metadata:
com.amazonaws.lambda:
egress_gateway: true
load_assignment:
cluster_name: lambda_egress_gateway # does this have to match? seems redundant
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: lambda.us-west-2.amazonaws.com
port_value: 443
transport_socket:
name: envoy.transport_sockets.tls
typed_config:
"@type": type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.UpstreamTlsContext
sni: "*.amazonaws.com"
Statistics¶
The AWS Lambda filter outputs statistics in the http.<stat_prefix>.aws_lambda. namespace. The | stat prefix comes from the owning HTTP connection manager.
Name |
Type |
Description |
---|---|---|
server_error |
Counter |
Total requests that returned invalid JSON response (see payload_passthrough) |
upstream_rq_payload_size |
Histogram |
Size in bytes of the request after JSON-tranformation (if any). |