Context-Server

The Context Server provides capabilities to serve and manage NGSI-LD Contexts. It provides multiple options for storage backends to allow environmental flexibility.

The current api can be viewed here: Swagger-UI

Configuration

The only general required configuration is the general.baseUrl. It should be set to the url that ContextServer is available at, in order to be able to build a sufficent link-header on creation and list retrieval. The context URLs will be constructed after the following pattern:

<BASE_URL>/jsonldContexts/<CONTEXT_ID>, f.e. http://context-server.fiware.org/jsonldContexts/myFancyContext.json

Cache control

In order to provide information about context-caching, the maxAge for Cache-Control can be set. It will default to max(1 year) if not configured.

general.maxAge: 31536000

Storage options

Multiple options for storage of the contexts are available. Every instance can only use one storage and multiple instances of distributed context servers can only use one shared backend.

In Memory

⚠️ In memory storage should only be used in single instance setups, since no distribution between multiple instances happens. It does not persist anything.

Enable: memory.enabled: true

Local Disc

⚠️ Local Disc storage should only be used in single instance setups or setups with an underlying (transparently) distributed filesystem, since no distribution between multiple instances happens.

Enable: local.enabled: true

Properties:

Property	Env-Var	Description	Default	Required
local.contextFolder	LOCAL_CONTEXTFOLDER	Local folder for the context's to be stored.	ld-contexts	true

In order to use Local-Disk storage, the correct read and write permissions need to be set.

GCS

Enable: gcs.enabled: true

Properties:

Property	Env-Var	Description	Default	Required
gcs.bucketName	GCS_BUCKETNAME	Name of the bucket to be used for storage.	my-contexts	true

In order to enable context storage on GCS, the Google Service Account credentials need to be provided. A service-account json file should be created as described(Google-Doc) and provided with the environment variable GOOGLE_APPLICATION_CREDENTIALS set to the file's path.

FTP

⚠️ This is currently considered to be experimental and not properly tested, yet.

Enable: ftp.enabled: true

Properties:

Property	Env-Var	Description	Default	Required
ftp.hostname	FTP_HOSTNAME	Hostname of the ftp to be used.	empty	true
ftp.port	FTP_PORT	Port of the ftp to be used.	21	true
ftp.contextFolder	FTP_CONTEXTFOLDER	Folder to store the contexts at.	/my-contexts	true
ftp.secured	FTP_SECURED	Does the ftp require username/password authentication	false	true
ftp.username	FTP_USERNAME	Username to be used for authentication on ftp.	user	false
ftp.password	FTP_PASSWORD	Password to be used for authentication on ftp.	password	false