google-cloud-platform google-artifact-registry

Downloading file from google artifact registry doesn't return a thing

I'm trying to use GCP API to download a file from Artifact Registry, and I don't understand how to do it.

The doc (link) states that

Response body - If successful, the response body is empty.

But it also states that this method:

Download a file.

So where should I find the said file?

I tried it with Postman and curl, and as described - the content is empty and I don't get the file:

$ curl --location 'https://artifactregistry.us-central1.rep.googleapis.com/v1/projects/<PROJ_ID>/locations/us-central1/repositories/<REPO_NAME>/files/<ARTIFACT_NAME>:<VERSION>:<FILE_PATH>:download' --header 'Authorization: Bearer ...'
{}

If I omit the ":download" part to use the 'get' command (link) I'm getting a valid and correct response with all the metadata:

$ curl --location 'https://artifactregistry.us-central1.rep.googleapis.com/v1/projects/<PROJ_ID>/locations/us-central1/repositories/<REPO_NAME>/files/<ARTIFACT_NAME>:<VERSION>:<FILE_PATH>' --header 'Authorization: Bearer ...'
{
  "name": "projects/.../locations/us-central1/repositories/.../files/...:...:...",
  "sizeBytes": "1373",
  "hashes": [ ... ],
  "createTime": "...",
  "updateTime": "...",
  "owner": "projects/.../locations/us-central1/repositories/.../packages/.../versions/..."
}

Any direction?

Solution

gcloud's --log-http flag is priceless in understanding the underlying (REST) calls made by gcloud.

PROJECT="..."
LOCATION="..."
REPO="..."

Pick one of the following and assign to FILE:

gcloud artifacts files list \
--location=${LOCATION} \
--repository=${REPO} \
--project=${PROJECT} \
--format="value(name)"

Then observe gcloud --log-http:

gcloud artifacts files download ${FILE} \
--location=${LOCATION} \
--repository=${REPO} \
--project=${PROJECT} \
--destination=.

And recreate using curl:

TOKEN=$(gcloud auth print-access-token)

NAME="projects/${PROJECT}/locations/${LOCATION}/repositories/${REPO}/files/${FILE}"

curl \
--get \
--header "Authorization: Bearer ${TOKEN}" \
--data-urlencode "alt=media" \
"https://artifactregistry.googleapis.com/v1/${NAME}:download" \
--output foo

ls -la foo