仅在检索期间出现重复性错误：boto.exception.NoAuthHandlerFound

Question

When attempting to retrieve a file that was backed up to a DigitalOcean S3 compatible instance using these commands...

$ source "$HOME/.duplicity/.env_variables.conf"
$ sudo duplicity --verbosity notice --encrypt-sign-key=$GPG_KEY --log-file ~/.duplicity/info.log --file-to-restore <path to file> s3://sfo2.digitaloceanspaces.com/<my server> <path to file>

...I get this error...

boto.exception.NoAuthHandlerFound: No handler was ready to authenticate. 1 handlers were checked. ['HmacAuthV1Handler'] Check your credentials

...even though as of last night the nightly backups are still successful using this bash script...

#!/bin/bash

HOME=<my home path>
source "$HOME/.duplicity/.env_variables.conf"
...
sync_results=`duplicity \
    --verbosity notice \
    --asynchronous-upload \
    --encrypt-sign-key="$GPG_KEY" \
    --log-file "$HOME/.duplicity/info.log" \
    /srv/samba/share \
    s3://sfo2.digitaloceanspaces.com/<my server>`
...

A month ago that retrieval command was successful. So something has changed since. The error points to an issue with credentials but both the command and the bash script source from the same .env file that contain the credentials.

All my research so far points to this being a boto issue, but until now I haven't had to touch boto to make things work correctly.

Any ideas?

PS: configuration details...

Local machine: Ubuntu 20.04 LTS, duplicity 0.8.12
DigitalOcean:  Ubuntu 18.04 LTS, duplicity 0.8.23

EDIT: mis-referenced cloud provider

Answer 1

might be caused by an upgrade to duplicity 0.8.23 which changed the default s3 backend to boto3. this changed how s3 access, especially with different end points, needs to be set up.

you can check if using boto+s3:// mitigates the issue, if so you may decide to stick with it or adapt to boto3+s3:// which is now the default for the alias s3://

the current0.8.23 man page reads

boto3 backend example backup command line:

AWS_ACCESS_KEY_ID=<key_id> AWS_SECRET_ACCESS_KEY=<access_key> duplicity /some/path s3:///bucket/subfolder

you may add --s3-endpoint-url (to access non Amazon S3 services or regional endpoints) and may need --s3-region-name (for buckets created in specific regions) and other --s3-... options documented above.

legacy boto backend example backup command line:

AWS_ACCESS_KEY_ID=<key_id> AWS_SECRET_ACCESS_KEY=<access_key> duplicity /some/path boto+s3://[host:port]/bucket/subfolder

The url host setting is optional and allows to define a custom endpoint host. you may add --s3-european-buckets and other s3 options documented above if needed.