Short version: run the same Docker image you use in Fargate, point it at Prefect Cloud via env vars, and either mount your local repo into the container or have the container clone from GitHub at runtime. Both approaches let you test locally without stuffing credentials into Prefect Cloud. Here are two solid ways to do it. Option A — Mount your local code (fastest feedback, no GitHub creds needed) - Use your prod image (or a dev variant), and mount your repo into the container. - Set Prefect Cloud auth via env vars so the run shows up in Cloud. Example:

docker run --rm -it \
  -e PREFECT_API_URL="<https://api.prefect.cloud/api/accounts/<account_id>/workspaces/<workspace_id>>" \
  -e PREFECT_API_KEY="$PREFECT_API_KEY" \
  -e PREFECT_LOGGING_LEVEL=INFO \
  -v "$(pwd)":/opt/project \
  --workdir /opt/project \
  <your-prod-image> \
  bash -lc "python -c 'from flows.my_flow import my_flow; my_flow(param=\"dev-test\")'"

- Replace

flows.my_flow:my_flow

with your entrypoint. - This runs the flow locally, reports to Prefect Cloud, and avoids any GitHub dance. Option B — Clone from GitHub inside the container (mirrors prod) If your prod containers pull code at runtime, you can do the same locally with

Flow.from_source(...)

. Keep GitHub credentials out of Prefect Cloud by forwarding your SSH agent or passing a temporary token locally. SSH agent forwarding (recommended for private repos):

docker run --rm -it \
  -e PREFECT_API_URL="<https://api.prefect.cloud/api/accounts/<account_id>/workspaces/<workspace_id>>" \
  -e PREFECT_API_KEY="$PREFECT_API_KEY" \
  -v $SSH_AUTH_SOCK:/ssh-agent \
  -e SSH_AUTH_SOCK=/ssh-agent \
  -v ~/.ssh/known_hosts:/root/.ssh/known_hosts:ro \
  <your-prod-image> \
  bash -lc '
python - <<PY
from prefect.flows import Flow
flow = Flow.from_source(
    source="git@github.com:owner/repo.git",
    entrypoint="path/to/flow.py:my_flow"
)
flow(param="dev-test")
PY
'

HTTPS with a temporary token (works too; just don’t bake it into the image):

docker run --rm -it \
  -e PREFECT_API_URL="<https://api.prefect.cloud/api/accounts/<account_id>/workspaces/<workspace_id>>" \
  -e PREFECT_API_KEY="$PREFECT_API_KEY" \
  -e GITHUB_TOKEN="$GITHUB_TOKEN" \
  <your-prod-image> \
  bash -lc '
python - <<PY
from prefect.flows import Flow
token = __import__("os").environ["GITHUB_TOKEN"]
url = f"https://{token}:x-oauth-basic@github.com/owner/repo.git"
flow = Flow.from_source(url, "path/to/flow.py:my_flow")
flow(param="dev-test")
PY
'

Notes and gotchas - Prefect 3.x: calling the flow directly (e.g.,

my_flow()

) will create a run in Prefect Cloud if

PREFECT_API_URL

and

PREFECT_API_KEY

are set. No deployment required for local testing. -

Flow.from_source(...)

works fine locally and mirrors your “pull code at runtime” design. - Keep secrets local: forward your SSH agent or use a short-lived `GITHUB_TOKEN`; don’t store repo creds in Prefect Cloud. - Use the exact image you run in Fargate to match system deps. Your future self will thank you. Want a docker-compose example or a snippet that matches your repo layout and entrypoint exactly? Point me at your flow’s entrypoint and the image name, and I’ll wire it up.