Emissary is a proxy service written in Rust. It can be used to log boundary events of a service, such as the start and end of an HTTP request.

$ ./emissary -c emissary.toml

Below is the schema for the configuration file.

The HTTP address and port to run Emissary on.

[http]
address = "127.0.0.1"
port = 8080

The HTTP address and port the main application is on.

[proxy]
address = "127.0.0.1"
port = 8082

Configures the logging of Emissary.

Determines the logging mode of Emissary. There are two options: json and plain.

[logging]
# Logs are written in JSON format
mode = "json"

[logging]
# Logs are written in plain format
mode = "plain"

Configures the format of the JSON logs.

[logging.json.format]
request.id = "%{UUID()}"
request.method = "%{METHOD}"
request.uri = "%{URI}"

{
  "request": {
    "id": "b5f8f8f8-f8f8-f8f8-f8f8-f8f8f8f8f8f8",
    "method": "GET",
    "uri": "/"
  }
}

Configures the format of the plain logs.

[logging.plain.format]
ID = "%{UUID()}"
Method = "%{METHOD}"
URI = "%{URI}"

2022-06-10T01:50:23.490857Z  INFO ID="c9035e94-fc3c-43a3-a4ca-93aecbb7b49d" Method="GET" Status="200" URI="/get"

Logging as a number of builtin operations that can be used.

See the emissary.toml in the examples directory.

{
  "details": {
    "duration_ms": "1",
    "duration_ns": "1165694",
    "duration_s": "0"
  },
  "request": {
    "id": "8c51cff7-0a8b-48c2-9bc1-2712c3712f79",
    "method": "GET",
    "uri": "/get",
    "version": "1.0.0"
  },
  "response": {
    "content_type": "text/plain; charset=utf-8",
    "status_code": 200
  }
}

2022-06-10T01:50:23.490857Z  INFO ContentType="text/plain; charset=utf-8" Duration(ms)="1" Duration(ns)="1314047" Duration(s)="0" ID="c9035e94-fc3c-43a3-a4ca-93aecbb7b49d" Method="GET" Status="200" URI="/get" Version="1.0.0" 

• Database Logging
• Message Queue Logging
• Add support for custom extensions
• Log output