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The Xmidt server for delivering events written in Go.


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(pronounced "kuh-doo-see-us")

Build Status Go Report Card Quality Gate Status Apache V2 License GitHub Release


The XMiDT server for delivering events from talaria to the registered consumer. Refer the overview docs for more information on how caduceus fits into the overall picture.

Table of Contents

Code of Conduct

This project and everyone participating in it are governed by the XMiDT Code Of Conduct. By participating, you agree to this Code.


Caduceus has one function: to deliver events to a consumer. To enable this, caduceus has three endpoints: 1) receive events, 2) register webhooks, and 3) get webhooks.

Notify - api/v3/notify endpoint

The notify endpoint will accept a msgpack encoding of a WRP Message. If a webhook is registered and matches the device regex and event regex, the event will be sent to the webhook's registered url. To register a webhook, refer to the webhook registration section

Webhook - /hook endpoint

To register a webhook and get events, the consumer must send an http POST request to caduceus that includes the http url for receiving the events and a list of regex filters. The following is an example request. Note: this is not a valid json because of the added comments.

  "config" : {
    # The url to push events to.
    "url" : "http://localhost:8080/webhook",

    # The content type event.
    # (Optional) defaults to msgpack.
    "content_type" : "application/json",

    # The secret used for SHA1 HMAC.
    # Used to validate the received payload.
    # (Optional) defaults to no sha1 hmac.
    "secret" : "secret",

    # Alternative urls to send requests too. A list of server urls to use in
    # round robin for sending events.
    # (Optional) defaults to no alternative urls.
    "alt_urls" : [

  # The URL to notify when we cut off a client due to overflow.
  # (Optional) defaults no notification of error.
  "failure_url" : "http://localhost:8080/webhook-failure",

  # The list of regular expressions to match event type against.
  # Warning: This is a very expensive webhook registration. This is not recommended for production.
  # This registration will be sent all events.
  "events" : [

  # matcher type contains values to match against the metadata.
  # currently only device_id is supported.
  # (Optional) defaults to all devices.
  "matcher" : {
    "device_id": [


Once everything is up and running you can start sending requests. Bellow are a few examples.

Create a hook

curl -X POST \
  http://localhost:6000/hook \
  -H 'Authorization: Basic YXV0aEhlYWRlcg==' \
  -H 'Content-Type: application/json' \
  -d '{
  "config": {
		"url" : "",
		"content_type" : "application/json"
  "events": [
  "duration": 120,
  "address": ""

Send an Event

curl -X POST \
  http://localhost:6000/api/v3/notify \
  -H 'Authorization: Basic YXV0aEhlYWRlcg==' \
  -H 'Content-Type: application/msgpack' \
  --data "@msg.bin"

where msg.bin is a msgpack encoded json

List Hooks

curl -X GET \
  http://localhost:6000/hooks \
  -H 'Authorization: Basic YXV0aEhlYWRlcg=='

Get Health

curl http://localhost:6001/health

GET some pprof stats

curl http://localhost:6002/debug/pprof/mutex



In order to build from the source, you need a working Go environment with version 1.11 or greater. Find more information on the Go website.

You can directly use go get to put the caduceus binary into your GOPATH:

GO111MODULE=on go get

You can also clone the repository yourself and build using make:

mkdir -p $GOPATH/src/
cd $GOPATH/src/
git clone
cd caduceus
make build


The Makefile has the following options you may find helpful:

  • make build: builds the caduceus binary
  • make docker: fetches all dependencies from source and builds a caduceus docker image
  • make local-docker: vendors dependencies and builds a caduceus docker image (recommended for local testing)
  • make test: runs unit tests with coverage for caduceus
  • make clean: deletes previously-built binaries and object files


First have a local clone of the source and go into the root directory of the repository. Then use rpkg to build the rpm:

rpkg srpm --spec <repo location>/<spec file location in repo>
rpkg -C <repo location>/.config/rpkg.conf sources --outdir <repo location>'


The docker image can be built either with the Makefile or by running a docker command. Either option requires first getting the source code.

See Makefile on specifics of how to build the image that way.

If you'd like to build it without make, follow these instructions based on your use case:

  • Local testing
go mod vendor
docker build -t caduceus:local -f deploy/Dockerfile .

This allows you to test local changes to a dependency. For example, you can build a caduceus image with the changes to an upcoming changes to webpa-common by using the replace directive in your go.mod file like so:

replace v1.10.2 => ../webpa-common

Note: if you omit go mod vendor, your build will fail as the path ../webpa-common does not exist on the builder container.

  • Building a specific version
git checkout v0.4.0
docker build -t caduceus:v0.4.0 -f deploy/Dockerfile .

Additional Info: If you'd like to stand up a XMiDT docker-compose cluster, read this.


A helm chart can be used to deploy caduceus to kubernetes

helm install xmidt-caduceus deploy/helm/caduceus


For deploying a XMiDT cluster refer to getting started.

For running locally, ensure you have the binary built. If it's in your GOPATH, run:


If the binary is in your current folder, run:



Refer to