"unsupported opentelemetry exporter None" with "docker-compose up"

[greatvovan]

Description

Today I and some of my colleagues started experiencing this error:

% docker-compose up       
[+] Building 0.0s (0/0)                                                                                                                    docker:desktop-linux
unsupported opentelemetry exporter None

Steps To Reproduce

Working on the sources I was able to reproduce it with the following minimized example:

FROM busybox
RUN touch my.txt

services:
  test:
    build:
      context: .

% docker-compose --debug up
DEBU[0000] Enabled Docker Desktop integration (experimental) @ unix:///Users/me/Library/Containers/com.docker.docker/Data/docker-cli.sock 
DEBU[0000] using default config store "/Users/me/.docker/buildx" 
[+] Building 0.0s (0/0)                                                                                                                    docker:desktop-linux
DEBU[0000] using default config store "/Users/me/.docker/buildx" 
DEBU[0000] otel error                                    error="<nil>"
DEBU[0000] otel error                                    error="<nil>"
unsupported opentelemetry exporter None

Compose Version

Docker Compose version v2.27.0-desktop.2

Docker Compose version v2.27.0-desktop.2

Docker Environment

Client:
 Version:    26.1.1
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.14.0-desktop.1
    Path:     /Users/me/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.27.0-desktop.2
    Path:     /Users/me/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.29
    Path:     /Users/me/.docker/cli-plugins/docker-debug
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/me/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.23
    Path:     /Users/me/.docker/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.4
    Path:     /Users/me/.docker/cli-plugins/docker-feedback
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.1.0
    Path:     /Users/me/.docker/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/me/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.8.0
    Path:     /Users/me/.docker/cli-plugins/docker-scout

Server:
 Containers: 12
  Running: 0
  Paused: 0
  Stopped: 12
 Images: 91
 Server Version: 26.1.1
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: e377cd56a71523140ca6ae87e30244719194a521
 runc version: v1.1.12-0-g51d5e94
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.6.26-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 12
 Total Memory: 7.656GiB
 Name: docker-desktop
 ID: f24fc6e4-f6bf-4f82-bc78-117bbc7dc65e
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/me/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: daemon is not using the default seccomp profile

Anything else?

If I change docker-compose.yaml to

services:
  test:
    image: busybox

the up command succeeds. It looks like it happens only if build is involved.

If I add some long-running command (e.g. sleep 10), the otel-related messages keep appearing though container runs:

% docker-compose --debug up
DEBU[0000] Enabled Docker Desktop integration (experimental) @ unix:///Users/me/Library/Containers/com.docker.docker/Data/docker-cli.sock 
[+] Running 1/0
 ✔ Container analytics_service-test-1  Created                                                                                                             0.0s 
Attaching to test-1
DEBU[0005] otel error                                    error="<nil>"
test-1 exited with code 0
DEBU[0010] otel error                                    error="<nil>"
DEBU[0010] otel error                                    error="<nil>"

The error is happening on my MacOS 14.4.1 (23E224), and my colleagues who reporting the same use Mac as well as Windows machines. it looks like it appeared only today, they report it worked just yesterday.
EDIT: nope, it was another error on Windows machines.

[ndeloof]

Please check you have OTEL_TRACES_EXPORTER variable set. none value is supported but should be lowercase

[greatvovan]

export OTEL_TRACES_EXPORTER=none did not help, but OTEL_METRICS_EXPORTER=none did.

I wonder, though, since when it is a requirement to have these variables set with docker-compose? Is is documented somewhere? Why is unset variable not interpreted as none by default?

[ndeloof]

This is not the default value, this None (uppercase) is probably set in your environment.

[ndeloof]

Can you please try running docker buildx build . to build your Dockerfile and confirm you get a distinct behavior ?

[greatvovan]

Yes, your command succeeds in the same shell where docker-compose fails.

[ndeloof]

I can't tell what's wrong here. OTEL_METRICS_EXPORTER is the standard variable used to configure opentelemetry (https://opentelemetry.io/docs/languages/sdk-configuration/general/#otel_metrics_exporter) and value is set by end user's environment, not compose. Have you checked you don't have value set in your .env file ?

[greatvovan]

Okay, I found that I do have .env file and it has OTEL_METRICS_EXPORTER=None, which is needed for the containerized app. The requirement for the containerized app is to have the value as "None" verbatim (not lowercase). What I don't understand is why it affects the docker-compose utility itself, since as described in the documentation

An .env file in Docker Compose is a text file used to define environment variables that should be made available to Docker containers when running docker compose up. ... The .env file is the default method for setting environment variables in your containers.

I read it as the .env file is treated as a collection of environment variables that get propagated to the containers. In my user environment I have no OTEL_METRICS_EXPORTER variable set:

% echo .$OTEL_METRICS_EXPORTER.
..

Is it documented somewhere that the utility treats the .env file as its own environment?

[ndeloof]

Documentation is highly confusing regarding .env file, a rewrite is on its way (docker/docs#19541)
.env in your working directory is used to interpolate variables in your compose.yaml file, as described here but it is also used to configure Compose itself. This can be used to set COMPOSE_* variables and typically change OTEL_METRICS_EXPORTER. So the conflict here

The requirement for the containerized app is to have the value as "None" verbatim (not lowercase).

That's a bit weird as this is an non-standard value, but I assume you have no impact on this :) I guess your compose.yaml file has env_file: .env set for container, one option is for you to use a distinct file name and a dedicated xx.env file for this container, or you can also override value in compose.yaml with environment: OTEL_METRICS_EXPORTER: None (environment has precedence on env_file)