= Distributed James Server &mdash; blobstore.properties
:navtitle: blobstore.properties

== BlobStore

This file is optional. If omitted, the *cassandra* blob store will be used.

BlobStore is the dedicated component to store blobs, non-indexable content.
James uses the BlobStore for storing blobs which are usually mail contents, attachments, deleted mails...

You can choose the underlying implementation of BlobStore to fit with your James setup.

It could be the implementation on top of Cassandra or file storage service S3 compatible like Openstack Swift and AWS S3.

Consult link:https://github.com/apache/james-project/blob/master/server/apps/distributed-app/sample-configuration/blob.properties[blob.properties]
in GIT to get some examples and hints.

=== Implementation choice

*implementation* :

* cassandra: use cassandra based BlobStore
* objectstorage: use Swift/AWS S3 based BlobStore

WARNING: JAMES-3591 Cassandra is not made to store large binary content, its use will be suboptimal compared to
Alternatives (namely S3 compatible BlobStores backed by for instance S3, MinIO or Ozone)

The generated startup warning log can be deactivated via the `cassandra.blob.store.disable.startup.warning` environment
variable being positioned to `false`.

*deduplication.enable*: Mandatory. Supported value: true and false.

If you choose to enable deduplication, the mails with the same content will be stored only once.

WARNING: Once this feature is enabled, there is no turning back as turning it off will lead to the deletion of all
the mails sharing the same content once one is deleted.

NOTE: If you are upgrading from James 3.5 or older, the deduplication was enabled.

Deduplication requires a garbage collector mechanism to effectively drop blobs. A first implementation
based on bloom filters can be used and triggered using the WebAdmin REST API. See
xref:operate/webadmin.adoc#_running_blob_garbage_collection[Running blob garbage collection].

In order to avoid concurrency issues upon garbage collection, we slice the blobs in generation, the two more recent
generations are not garbage collected.

*deduplication.gc.generation.duration*: Allow controlling the duration of one generation. Longer implies better deduplication
but deleted blobs will live longer. Duration, defaults on 30 days, the default unit is in days.

*deduplication.gc.generation.family*: Every time the duration is changed, this integer counter must be incremented to avoid
conflicts. Defaults to 1.

=== Encryption choice

Data can be optionally encrypted with a symmetric key using AES before being stored in the blobStore. As many user relies
on third party for object storage, a compromised third party will not escalate to a data disclosure. Of course, a
performance price have to be paid, as encryption takes resources.

*encryption.aes.enable* : Optional boolean, defaults to false.

If AES encryption is enabled, then the following properties MUST be present:

 - *encryption.aes.password* : String
 - *encryption.aes.salt* : Hexadecimal string

The following properties CAN be supplied:

 - *encryption.aes.private.key.algorithm* : String, defaulting to PBKDF2WithHmacSHA512. Previously was
PBKDF2WithHmacSHA1.

WARNING: Once chosen this choice can not be reverted, all the data is either clear or encrypted. Mixed encryption
is not supported.

Here is an example of how you can generate the above values (be mindful to customize the byte lengths in order to add
enough entropy.

....
# Password generation
openssl rand -base64 64

# Salt generation
generate salt with : openssl rand -hex 16
....

=== Cassandra BlobStore Cache

A Cassandra cache can be enabled to reduce latency when reading small blobs frequently.
A dedicated keyspace with a replication factor of one is then used.
Cache eviction policy is TTL based.
Only blobs below a given threshold will be stored.
To be noted that blobs are stored within a single Cassandra row, hence a low threshold should be used.

.blobstore.properties cache related content
|===
| Property name | explanation

| cache.enable
| DEFAULT: false, optional, must be a boolean. Whether the cache should be enabled.

| cache.cassandra.ttl
| DEFAULT: 7 days, optional, must be a duration. Cache eviction policy is TTL based.

| cache.sizeThresholdInBytes
| DEFAULT: 8192, optional, must be a positive integer. Unit: bytes.
Supported units: bytes, Kib, MiB, GiB, TiB
Maximum size of stored objects expressed in bytes.
|===

=== Object storage configuration

==== AWS S3 Configuration

.blobstore.properties S3 related properties
|===
| Property name | explanation

| objectstorage.s3.endPoint
| S3 service endpoint

| objectstorage.s3.region
| S3 region

| objectstorage.s3.accessKeyId
| https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#access-keys-and-secret-access-keys[S3 access key id]

| objectstorage.s3.secretKey
| https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#access-keys-and-secret-access-keys[S3 access key secret]

| objectstorage.s3.http.concurrency
| Allow setting the number of concurrent HTTP requests allowed by the Netty driver.

| objectstorage.s3.truststore.path
| optional: Verify the S3 server certificate against this trust store file.

| objectstorage.s3.truststore.type
| optional: Specify the type of the trust store, e.g. JKS, PKCS12

| objectstorage.s3.truststore.secret
| optional: Use this secret/password to access the trust store; default none

| objectstorage.s3.truststore.algorithm
| optional: Use this specific trust store algorithm; default SunX509

| objectstorage.s3.read.timeout
| optional: HTTP read timeout. duration, default value being second. Leaving it empty relies on S3 driver defaults.

| objectstorage.s3.write.timeout
| optional: HTTP write timeout. duration, default value being second. Leaving it empty relies on S3 driver defaults.

| objectstorage.s3.connection.timeout
| optional: HTTP connection timeout. duration, default value being second. Leaving it empty relies on S3 driver defaults.

| objectstorage.s3.in.read.limit
| optional: Object read in memory will be rejected if they exceed the size limit exposed here. Size, exemple `100M`.
Supported units: K, M, G, defaults to B if no unit is specified. If unspecified, big object won't be prevented
from being loaded in memory. This settings complements protocol limits.
|===

==== Buckets Configuration

.Bucket configuration
|===
| Property name | explanation

| objectstorage.bucketPrefix
| Bucket is a concept in James and similar to Containers in Swift or Buckets in AWS S3.
BucketPrefix is the prefix of bucket names in James BlobStore

| objectstorage.namespace
| BlobStore default bucket name. Most of blobs storing in BlobStore are inside the default bucket.
Unless a special case like storing blobs of deleted messages.
|===

== Blob Export

Blob Exporting is the mechanism to help James to export a blob from an user to another user.
It is commonly used to export deleted messages (consult <a href="/server/config-vault">configuring deleted messages vault</a>).
The deleted messages are transformed into a blob and James will export that blob to the target user.

This configuration helps you choose the blob exporting mechanism fit with your James setup and it is only applicable with Guice products.

Consult https://github.com/apache/james-project/blob/master/server/apps/distributed-app/sample-configuration/blob.properties[blob.properties]
in GIT to get some examples and hints.

Configuration for exporting blob content:

.blobstore.properties content
|===
| blob.export.implementation

| localFile: Local File Exporting Mechanism (explained below). Default: localFile

| linshare: LinShare Exporting Mechanism (explained below)
|===

=== Local File Blob Export Configuration

For each request, this mechanism retrieves the content of a blob and save it to a distinct local file, then send an email containing the absolute path of that file to the target mail address.

Note: that absolute file path is the file location on James server. Therefore, if there are two or more James servers connected, it should not be considered an option.

*blob.export.localFile.directory*: The directory URL to store exported blob data in files, and the URL following
http://james.apache.org/server/3/apidocs/org/apache/james/filesystem/api/FileSystem.html[James File System scheme].
Default: file://var/blobExporting

=== LinShare Blob Export Configuration

Instead of exporting blobs in local file system, using https://www.linshare.org/en/index.html[LinShare]
helps you upload your blobs and people you have been shared to can access those blobs by accessing to
LinShare server and download them.

This way helps you to share via whole network as long as they can access to LinShare server.

To get an example or details explained, visit https://github.com/apache/james-project/blob/master/server/apps/distributed-app/sample-configuration/blob.properties[blob.properties]

*blob.export.linshare.url*: The URL to connect to LinShare

*blob.export.linshare.token*: The authentication token to connect to LinShare
