Package usage method

This article introduces you to the operations involved in the project space Package creator and Package consumer.

The use of package involves two subjects: the package creator and the package user.

The package creator provides the resources to be shared and the permissions to access it. It also allows the package user to install and use it.
The package user uses the package. After the package is published, the user can directly access the resource across projects.

The following is a description of the operations involved with the package creator and package user.

Package creator

Create package
```
create package <pkgname>;
```
Note
- Only the project owner has the permission to create a package.
- The name of the package cannot exceed 128 characters.
Add a resource to be shared to the package
```
    Add project_object to package package_name [with privileges] -- add objects to package
    Remove project_object from package package_name; -- remove object from package
    project_object ::= table table_name |
                   instance inst_name |
                   function func_name |
                   resource res_name
    privileges ::= action_item1, action_item2, ...
```
Additional considerations
- Currently, supported types of objects exclude projects. Therefore, you cannot use a package to create objects in other projects.
- When you add resources to a project, ensure that the entered object names do not contain the prefix of the project name. For example, if you want to add a table named table_test to a package in project prj1, the table name in the ADD statement cannot be prj1.table_test. Enter table_test as the table name in the statement.
- The objects themselves and the permission to perform operations on them are added to the package at the same time. When not passed (with privileges) even specifying an action permission, the default is read-only, that is, read/describe/select. The object and its permissions are treated as a whole and cannot be updated once added. If necessary, you can only delete and re-add.
- When an object is added to a package, it is not packaged as a snapshot, so subsequent object data changes, and access to the object through package authorization is also the current data of the object.

Allow other projects to use a package

allow project <prjName> to install package <pkgName> [using label <num>]

Revoke other projects’ permission to use a package

disallow project <prjName> to install package <pkgName>

Drop a package
```
Delete package <pkgname>;
```
View the list of packages already created and installed
```
Show packages;
```
View package details
```
Describe package <pkgname>;
```

Package users

Install package
```
Install package <pkgname>;
```
For package installation, the pkgName format is: <projectName>.<packageName>.

Note Only the project owner has permissions to perform this operation.
Uninstalling package
```
Uninstall package <pkgname>;
```
For package installation, the pkgName format is: <projectName>.<packageName>.<projectName>.<packageName>

View a package

    Show packages;
    View the list of packages already created and installed
    Describe package <pkgname>;
    View details of package

Client project grants access to package to other members or role of this project
The installed package is an independent type of MaxCompute object. To access resources in a package (resources shared with you by other projects), you must have the permission to read package.

If you do not have the Read permission, you must apply to the project owner or admin for the permission. The project owner or admin can grant permissions through ACL authorization or policy authorization.

Authorize package to user or role:
```
grant actions on package <pkgName> to user <username>;
grant actions on package <pkgName> to role <role_name>;
```
Note After authorization, user has access to the object in that package only in this project.
For example, the following ACL authorization allows the cloud account user odps_test@aliyun.com to access resources in the package:
```
    use prj2;
    install package prj1.testpkg;
    grant read on package prj1.testpackage to user aliyun$odps_test@aliyun.com;
```
Or allow all members of role role_dev to access resources in package:
```
use prj2;
    install package prj1.testpkg;
    grant read on package prj1.testpackage to role role_dev;
```

Example

Jack is the administrator of prj1. John is the administrator of prj2. To address some business needs, Jack wants to share some resources of prj1 (such as datamining.jar and sampletable) to John's prj2. If prj2 user Bob must access these resources, the prj2 administrator can self-authorize Bob through ACL administrator or policy authorization without Jack’s involvement.

Procedure:

Prj1 administrator Jack creates resources package in prj1.

    Use prj1;
    Create package datamicing; -- creating a package
    Add Resource dating. jar to package dating;-add resource to package
    Add Table sampletable to package dating; -- adding table to package
    Allow project prm9 to install package dating; -- sharing package to Project Space prm9

Prj2 administrator Bob installs a package in prj2.

    use prj2;
    install package prj1.datamining; -- installs a package
    describe package prj1.datamining; -- view a list of resources in the package

Bob self-authorizes the package.

    use prj2;
    grant Read on package prj1.datamining to user aliyun$bob@aliyun.com; -- authorization of Bob to use package via ACL