atomgraph/linkeddatahub repository overview

⁠Prerequisites

• bash shell 4.x. It should be included by default on Linux. On Windows you can install the Windows Subsystem for Linux⁠.
• Java's keytool⁠ available on $PATH. It comes with the JDK.
• openssl⁠ available on $PATH
• uuidgen⁠ available on $PATH
• Docker⁠ installed. At least 8GB of memory dedicated to Docker is recommended.
• Docker Compose⁠ installed

⁠Steps

1. Fork⁠ this repository and clone the fork into a folder
2. In the folder, create an .env file and fill out the missing values (you can use .env_sample⁠ as a template). For example:

   COMPOSE_CONVERT_WINDOWS_PATHS=1
   COMPOSE_PROJECT_NAME=linkeddatahub
   
   PROTOCOL=https
   HTTP_PORT=81
   HTTPS_PORT=4443
   HOST=localhost
   ABS_PATH=/
   
   [email protected]
   OWNER_GIVEN_NAME=John
   OWNER_FAMILY_NAME=Doe
   OWNER_ORG_UNIT=My unit
   OWNER_ORGANIZATION=My org
   OWNER_LOCALITY=Copenhagen
   OWNER_STATE_OR_PROVINCE=Denmark
   OWNER_COUNTRY_NAME=DK
   

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3. Setup SSL certificates/keys by running this from command line (replace $owner_cert_pwd and $secretary_cert_pwd with your own passwords):

   ./scripts/setup.sh .env ssl $owner_cert_pwd $secretary_cert_pwd 3650
   

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   The script will create an ssl sub-folder where the SSL certificates and/or public keys will be placed.
4. Launch the application services by running this from command line:

   docker-compose up --build
   

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   It will build LinkedDataHub's Docker image, start its container and mount the following sub-folders:
   • data where the triplestore(s) will persist RDF data
   • uploads where LDH stores content-hashed file uploads The first should take around half a minute as datasets are being loaded into triplestores. After a successful startup, the last line of the Docker log should read something like:

   linkeddatahub_1     | 09-Feb-2021 14:18:10.536 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in [32609] milliseconds
   

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5. Install ssl/owner/keystore.p12 into a web browser of your choice (password is the $owner_cert_pwd value supplied to setup.sh)
   • Google Chrome: Settings > Advanced > Manage Certificates > Import...
   • Mozilla Firefox: Options > Privacy > Security > View Certificates... > Import...
   • Apple Safari: The file is installed directly into the operating system. Open the file and import it using the Keychain Access⁠ tool (drag it to the local section).
   • Microsoft Edge: Does not support certificate management, you need to install the file into Windows. Read more here⁠.
6. Open https://localhost:4443/⁠ in that web browser

⁠Notes

• There might go up to a minute before the web server is available because the nginx server depends on healthy LinkedDataHub and the healthcheck is done every 20s
• You will likely get a browser warning such as Your connection is not private in Chrome or Warning: Potential Security Risk Ahead in Firefox due to the self-signed server certificate. Ignore it: click Advanced and Proceed or Accept the risk to proceed.
  • If this option does not appear in Chrome (as observed on some MacOS), you can open chrome://flags/#allow-insecure-localhost, switch Allow invalid certificates for resources loaded from localhost to Enabled and restart Chrome
• .env_sample and .env files might be invisible in MacOS Finder which hides filenames starting with a dot. You should be able to create it using Terminal⁠ however.
• On Linux your user may need to be a member of the docker group. Add it using

sudo usermod -aG docker ${USER}

and re-login with your user. An alternative, but not recommended, is to run

sudo docker-compose up

⁠Base URI

A common case is changing the base URI from the default https://localhost:4443/ to your own.

Lets use https://ec2-54-235-229-141.compute-1.amazonaws.com/linkeddatahub/ as an example. We need to split the URI into components and set them in the .env file using the following parameters:

PROTOCOL=https
HTTP_PORT=80
HTTPS_PORT=443
HOST=ec2-54-235-229-141.compute-1.amazonaws.com
ABS_PATH=/linkeddatahub/

ABS_PATH is required, even if it's just /.

⁠Dataspaces

Dataspaces are configured in config/system-varnish.trig⁠. Relative URIs will be resolved against the base URI configured in the .env file.

:warning: Do not use blank nodes to identify applications or services. We recommend using the urn: URI scheme, since LinkedDataHub application resources are not accessible under their own dataspace.

⁠Environment

LinkedDataHub supports a range of configuration options that can be passed as environment parameters in docker-compose.yml. The most common ones are:

CATALINA_OPTS

Tomcat's command line options⁠

SELF_SIGNED_CERT

true if the server certificate is self-signed

SIGN_UP_CERT_VALIDITY

Validity of the WebID certificates of signed up users (not the owner's)

IMPORT_KEEPALIVE

The period for which the data import can keep an open HTTP connection before it times out, in ms. The larger files are being imported, the longer it has to be in order for the import to complete.

MAX_CONTENT_LENGTH

Maximum allowed size of the request body, in bytes

MAIL_SMTP_HOST

Hostname of the mail server

MAIL_SMTP_PORT

Port number of the mail server

GOOGLE_CLIENT_ID

OAuth 2.0 Client ID from Google. When provided, enables the Login with Google authentication method.

GOOGLE_CLIENT_SECRET

Client secret from Google

The options are described in more detail in the configuration documentation⁠.

⁠Reset

If you need to start fresh and wipe the existing setup (e.g. after configuring a new base URI), you can do that using

sudo rm -rf data uploads && docker-compose down -v

:warning: This will remove the persisted data and files as well as Docker volumes.