Send gtm-sdk telemetry to Dash0 with the otel-collector

This guide walks through setting up Dash0 as a telemetry provider for the otel-collector.

Endpoints

Dash0 provides regional endpoints:

US: https://otel-ingest.us.dash0.com
EU: https://otel-ingest.eu.dash0.com

Choose the one nearest your data location.

Set up secrets in Infisical

Add three secrets to your Infisical project (dev environment):

1. DASH0_AUTH_TOKEN

Name: DASH0_AUTH_TOKEN
Value: Your Dash0 API token (looks like a long token string)
Type: Secret
Environment: dev

2. DASH0_OTLP_ENDPOINT

Name: DASH0_OTLP_ENDPOINT
Value: Your regional endpoint
- US: https://otel-ingest.us.dash0.com
- EU: https://otel-ingest.eu.dash0.com
Type: Secret
Environment: dev

3. DASH0_DATASET (Optional)

Name: DASH0_DATASET
Value: default (or your dataset name)
Type: Secret
Environment: dev

Set secrets via CLI

cd ~/Documents/ai

# Source your Infisical credentials
set -a && source .env.local && set +a

# Set each secret
infisical secrets set \
  DASH0_AUTH_TOKEN "your-token-here" \
  --env=dev \
  --projectId "$INFISICAL_PROJECT_ID" \
  --token "$INFISICAL_TOKEN"

infisical secrets set \
  DASH0_OTLP_ENDPOINT "https://otel-ingest.us.dash0.com" \
  --env=dev \
  --projectId "$INFISICAL_PROJECT_ID" \
  --token "$INFISICAL_TOKEN"

infisical secrets set \
  DASH0_DATASET "default" \
  --env=dev \
  --projectId "$INFISICAL_PROJECT_ID" \
  --token "$INFISICAL_TOKEN"

Deploy the collector

Once secrets are set, deploy the otel-collector:

cd ~/Documents/ai/gtm-sdk

# Source Infisical credentials
set -a && source ../ai/.env.local && set +a

# Deploy the collector (it will pick up Dash0 secrets)
infisical run --env=dev -- uv run modal deploy src/otel_collector.py

The collector image build fetches the secrets and embeds them, so when the container starts, Dash0 is already configured.

Verify configuration

Check that Dash0 was included in the collector config:

# From gtm-sdk root:
uv run python -c "
from src.otel_collector import build_collector_config
config = build_collector_config()
exporters = config.get('exporters', {})
print('Exporters:', list(exporters.keys()))
if 'otlphttp/dash0' in exporters:
    print('✓ Dash0 is configured')
else:
    print('✗ Dash0 is NOT configured')
"

Test telemetry flow

Use the verification script to test end-to-end telemetry:

cd ~/Documents/ai/gtm-sdk

# Set environment (usually injected via Infisical, but can override)
export DASH0_AUTH_TOKEN="your-token"
export DASH0_OTLP_ENDPOINT="https://otel-ingest.us.dash0.com"
# Collector fan-out is the default (app name hard-coded in libs/telemetry.py);
# only set this to override the app name, or to "" to force the direct fallback.
export TELEMETRY_COLLECTOR_APP="otel-collector"

# Run tests
uv run pytest tests/src/test_dash0_telemetry_integration.py -v

# Or emit test telemetry (requires collector running on Modal)
uv run scripts/verify_dash0_telemetry.py

Collector architecture

When the collector is deployed:

App/Webhook/CLI
    ↓ (Modal RPC spawn)
otel-collector function (Modal)
    ↓ (localhost OTLP)
otelcol sidecar (in container)
    ├─→ Dash0
    ├─→ HyperDX (if configured)
    └─→ Logfire (if configured)

The app-side exporter serializes each batch to OTLP protobuf and spawns the collector function fire-and-forget. The collector function hands it to a localhost otelcol process, which handles retry, queueing, and fan-out to all providers. See libs/telemetry.py and src/otel_collector.py for implementation details.

Troubleshooting

Secrets not found

# Verify secrets exist in Infisical:
set -a && source .env.local && set +a
infisical secrets get DASH0_AUTH_TOKEN --env=dev \
  --projectId "$INFISICAL_PROJECT_ID" \
  --token "$INFISICAL_TOKEN"

Collector not starting

Check the Modal logs for the otel-collector app:

modal logs otel-collector --follow

Look for errors like “exporters config: *conf.ExportersConfig.Validate()…” which indicates a config build error.

No telemetry in Dash0

Verify the collector is running: modal serve src/otel_collector.py
Check Modal logs for export errors
Verify the OTLP endpoint is reachable from the collector container
Check that the Bearer token is valid

Mixing Dash0 with other providers

You can enable multiple providers simultaneously — the collector will fan-out to all configured exporters:

# These don't conflict; all three will export
DASH0_AUTH_TOKEN=...
HYPERDX_API_KEY=...
LOGFIRE_WRITE_TOKEN=...

Reference

Dash0 Docs
OpenTelemetry Collector OTLPHTTP Exporter
src/otel_collector.py — Collector app and config builder
libs/telemetry.py — App-side telemetry initialization

​Endpoints

​Set up secrets in Infisical

​1. DASH0_AUTH_TOKEN

​2. DASH0_OTLP_ENDPOINT

​3. DASH0_DATASET (Optional)

​Set secrets via CLI

​Deploy the collector

​Verify configuration

​Test telemetry flow

​Collector architecture

​Troubleshooting

​Secrets not found

​Collector not starting

​No telemetry in Dash0

​Mixing Dash0 with other providers

​Reference