postgres:// scheme added to bucket address that already has scheme

[mark-rushakoff]

What happened:

I am using juicefs-csi-driver with Nomad, with both meta and data stores in postgres. Adding a volume was failing with a cryptic error:

lookup postgres on <my dns server>:53: server misbehaving

What you expected to happen:

Volume created correctly.

How to reproduce it (as minimally and precisely as possible):

I was using this volume definition for Nomad:

id = "demo-jfs"
name = "demo-jfs"

type = "csi"
plugin_id = "juicefs"

capacity_min = "1MiB"
capacity_max = "10MiB"

capability {
  access_mode     = "single-node-writer"
  attachment_mode = "file-system"
}

secrets {
  name = "timestamp-demo-jfs"
  metaurl = "postgres://juicefs:[email protected]/juicefs_meta"
  bucket = "postgres://juicefs:[email protected]/juicefs_data"
  storage = "postgres"
}

I later found out that it was incorrect to have the postgres:// scheme on the secrets.bucket value, but I had to spend a lot of time debugging before I learned that. I eventually found that

juicefs/pkg/object/sql.go

Line 163 in 5427991

uri = "postgres://" + uri

could simply check strings.HasPrefix(uri, "postgres://") before adding that prefix to the uri.

Alternatively, the volume could have been rejected for already containing a scheme with storage=postgres. Either way would have saved me quite a bit of time.

Environment:

• JuiceFS version (use juicefs --version) or Hadoop Java SDK version: docker.io/juicedata/juicefs-csi-driver:v0.17.0
• Cloud provider or hardware configuration running JuiceFS: Locally with Nomad

[zhijian-pro]

I think your bucket format is wrong, the format of postgres as an object store is different than when it is a meta.
as meta:

juicefs format \
    --storage s3 \
    ... \
    "postgres://user:[email protected]:5432/juicefs" \
    pics

as storage:

juicefs format \
    --storage postgres \
    --bucket <host>:<port>/<db>[?parameters] \
    --access-key <username> \
    --secret-key <password> \
    ... \
    myjfs

You can refer to this link

[mark-rushakoff]

I think your bucket format is wrong

Yes, I eventually figured that out:

I later found out that it was incorrect to have the postgres:// scheme on the secrets.bucket value

It took me several hours to figure out that postgres:// was required for meta but unallowed for storage.

I filed an issue because of the poor user experience it took to realize that the storage url must not contain a scheme.

My ask in the issue was either:

• Allow postgres:// in the storage URL when the driver is postgres
• Or detect that the URL contains a scheme (postgres:// or http://, etc.), and reject the configuration

This was especially confusing because the Nomad example at https://juicefs.com/docs/csi/csi-in-nomad/#community-edition shows bucket="http://172.16.254.29:9000/minio/test", which makes it look like the scheme is required.

[zhijian-pro]

To improve the ease of use of the product, we will ignore the bucket url schema. #2750