This post is more than 5 years old
5 Posts
0
3876
Atmos Emc Metadata ,acl and paths on atmos
Hi,
I'm new at Atmos EMC, it is wanted me to use Atmos to store our file management system files.We use .Net technology as development environment, I use atmos-dotnet wrapper.It is easy to use but I have some questions about ACLs, Metadata and ObjectPaths.I want to understand exact purpose why we use ACLs, Metadata and ObjectPaths.I tried to find documents on site but links are broken I think.Is there anybody here to explain the purpose.Because to query an object we always use objectid, so why we need metadata etc.Is there a management interface to view files on atmos without using Atmos API ?, I have no idea.
Thanks.
chris_arnett
110 Posts
1
January 20th, 2016 07:00
@ceycey, sorry for the extremely late reply. I will try to address your question in two parts. Part 1 will cover metadata and paths.
Atmos provides two methods of identifying objects. Object ID is one, which is assigned to all objects by Atmos. The REST context for object IDs is /rest/objects. Another optional method is namespace path. To have a path, an object must be initially created with that path. The REST context for the namespace is /rest/namespace. The namespace is roughly equivalent to a filesystem directory structure. There are nestable directories and objects can be placed at any level. This is useful in cases where you are migrating an application from filesystem storage to Atmos, or in any other case where naming your objects is useful. Note that namespace objects also have an object ID and can be referenced by either.
Metadata is a set of simple key-value pairs associated with a particular object. In most cases, this metadata is only accessible directly through the object (you must know the object's identifier). You can also make some metadata "listable", which means the name (not the value) is indexed and objects may be queried based on the tag name. This may be useful if there is additional lookup criteria (other than a namespace path) you need to locate objects associated with a piece of information, such as a document ID or account number.
Be aware that there are some performance-based limitations on the namespace and listable tags. The fastest and most scalable way to access objects is still by object ID. We recommend that customers use a primary application database that simply references object IDs in Atmos.
For more information about the namespace and metadata, see chapter 1 of the Atmos Programmer's Guide.
chris_arnett
110 Posts
1
January 20th, 2016 08:00
Part 2 will cover ACLs
Access Control Lists in Atmos are no different from any other application. However, Atmos contains its own user database for data access and does not integrate directly with any other auth systems. So if you have two users in the same subtenant and you want them to share data, you can give Bob read access to John's objects by adding Bob to the individual objects' ACLs. Note that in the namespace, directory permissions have a different meaning, and they are not recursive. Also note that there is no cross-subtenant access, so ACLs are only applicable in the context of a single subtenant.
More information about ACLs can be found in chapter 6 of the Atmos Programmer's Guide.