Use appendfromfile to append content to an object - Object Storage Service

Use the appendfromfile command to append the contents of a local file to an appendable object in Object Storage Service (OSS).

Append upload suits scenarios where data grows continuously, such as adding new log entries to a log file or adding video segments to a media file as they are generated. Unlike a standard upload, each appendfromfile call adds to the existing object rather than replacing it.

Prerequisites

Before you begin, make sure you have:

The oss:GetObject and oss:PutObject permissions on the target bucket. For details, see Attach a custom policy to a RAM user.
ossutil installed. For ossutil 1.6.16 and later, use ossutil directly as the binary name. For earlier versions, update the binary name based on your operating system. For details, see ossutil command reference.

Command syntax

ossutil appendfromfile localfilename oss://bucketname/objectname
[--meta <value>]

Parameter/Option	Description
`localfilename`	Full path of the local file to upload.
`bucketname`	Name of the bucket that contains the target object.
`objectname`	Name of the object to append content to. You can keep the original file name or specify a different one.
`--meta`	Metadata to set on the object. Only takes effect the first time you run `appendfromfile` on an object. Subsequent calls ignore this option. Example: `--meta "x-oss-object-acl:private"`. To update metadata after the initial upload, use the set-meta command.

Examples

The following examples show two stages of an append upload workflow: creating an appendable object with an initial upload, then appending more data to it.

Upload a file and set the ACL

Run the following command to upload exampleobject.txt from your local root directory to examplebucket and set the access control list (ACL) to private:

ossutil appendfromfile exampleobject.txt oss://examplebucket/exampleobject.txt --meta "x-oss-object-acl:private"

Sample output:

total append 5(100.00%) byte,speed is 0.00(KB/s)
local file size is 5,the object new size is 5,average speed is 0.04(KB/s)

The output confirms the file is uploaded and stored as exampleobject.txt with a size of 5 bytes.

Append content to an existing object

Run the following command to append the contents of dest.txt to the existing exampleobject.txt object:

ossutil appendfromfile dest.txt oss://examplebucket/exampleobject.txt

Sample output:

total append 150(100.00%) byte,speed is 0.00(KB/s)
local file size is 150,the object new size is 150,average speed is 1.19(KB/s)

The output confirms that 150 bytes were appended and the object's new total size is 150 bytes.

To continue appending data, replace dest.txt with the path to the next file you want to append.

Usage notes

The --meta option only takes effect the first time you run appendfromfile on an object. Use the set-meta command to update metadata after the initial upload.
For more information about append upload, see Append upload.

Common options

To access a bucket in a different region or owned by a different Alibaba Cloud account, pass the following options:

Option	Description
`-e`	Endpoint of the region where the bucket is located.
`-i`	AccessKey ID of the Alibaba Cloud account that owns the bucket.
`-k`	AccessKey secret of the Alibaba Cloud account that owns the bucket.

Example: Append upload to a bucket in the China (Shanghai) region owned by a different account:

ossutil appendfromfile exampleobject.txt oss://examplebucket/exampleobject.txt -e shanghai.aliyuncs.com -i yourAccessKeyID -k yourAccessKeySecret

For a full list of common options, see Common options.