Image Origin Tracing
US3 provides an Image Origin Tracing feature. After the origin tracing rules are configured, when the data you request from US3 storage space does not exist, you can obtain the requests for data in various ways through origin tracing settings, meeting your needs for data heat migration and specific request redirection.
After setting the origin tracing rules, each GET or HEAD request URL for US3 can be matched according to the set rules, and then the origin tracing is carried out according to the set rules. Up to 5 rules can be configured, and they are matched in orders until an effective rule is met. The type of origin tracing is mirror mode.
- Mirror mode: if the origin tracing rules have been configured, then when a non-existent file is subjected to GET or HEAD operation, the source site will be asked for the file, which is then returned to the user and simultaneously written into US3.
Under mirror mode, if the Range header field is carried in the request, the complete origin file will finally be written into US3, instead of only writing the part of data indicated by Range.
Image processing requests will not trigger image origin tracing.
Application Scenarios
Most of your source files are stored in US3 storage space, a small number of files are in the customer source site, but a small amount of files continue to be written to the source site, which can be directly sourced from the source site through the image origin tracing function to get files, so as to achieve smooth migration of business.
Setting Origin Tracing Rules
The user specifies the file prefix and source site address. When US3 does not have the file, US3 will automatically fetch and save the file from the specified source site according to the file prefix, and return it to the user.
- Choose the corresponding space, select the Image Origin Tracing button in the right operation.
- Click the Add Origin Tracing Rule button.
- Add an Origin Tracing Rule interface.
- Fill in the file prefix and origin tracing address, the file prefix is the actual path of the designated source site, if it is the root directory, then the file prefix is empty.
Example: Through US3 access to other source sites ‘test’ the file under the folder, set origin tracing rules, file prefix is ‘test’, origin tracing address is source site address.
Note: The tracing back address only supports HTTP access
- Access the files in this folder of other source sites through US3.
- US3 also automatically saved the file.
Remarks
- Currently, each single-region storage space (Bucket) can create 5 origin tracing rules, the prefix is unique and cannot be repeated
- Globalized space management does not currently support setting origin tracing rules
- Sub-accounts need to enable API key permissions (FAQ, if the sub-account has not enabled the API key, US3 will not be able to upload the backtrace file to the user’s Bucket
- It does not support triggering image origin tracing in image processing requests, that is, it does not support the target file of image processing as a file in the source site (users can firstly initiate a request for origin tracing under the mirror mode, and after the origin tracing is successful, they can then initiate an image processing request)
- It does not support the source site as a private US3 or other third-party private Bucket
- It does not support the source site address using the US3 Intranet domain name
- It does not support MD5 verification
- If the source site returns a 3xx redirection response, US3 will reinitiate a request to the new source site address, with a maximum recursion times of 10.