TAS NFS Volume Watch Service Example

Setup

Create NFS service

cf create-service nfs Existing SERVICE-INSTANCE-NAME -c '{"share":"<hostname-and-path-to-nfs-volume>", "version":"4.0"}'

Build and Push the App

./gradlew assemble
cf push -p build/libs/cf-nfs-watchservice-0.0.1-SNAPSHOT.jar --no-start

Bind NFS Service

cf bind-service cf-nfs-watchservice SERVICE-INSTANCE-NAME -c '{"uid":"<provided>","gid":"<provided>","mount":"/var/watcherdemo"}'

Start the App

cf start cf-nfs-watchservice

You should see the following output in the logs upon first startup:

2020-06-03T11:55:29.69-0500 [APP/PROC/WEB/0] OUT 2020-06-03 16:55:29.696  INFO 25 --- [           main] c.e.c.UploadWatcherService               : Upload directory created: /var/watcherdemo/upload

Generate and Watch Uploads

Generate a Random File

curl -X POST https://cf-nfs-watchservice.yourdomain.com/generate
{"generated":true}

Observe the Logs

You should see log output like the following indicating the file was created and a watch event was triggered:

2020-06-03T12:00:50.44-0500 [APP/PROC/WEB/0] OUT 2020-06-03 17:00:50.440  INFO 25 --- [nio-8080-exec-8] c.example.cfnfswatchservice.RandomFile   : File created: /var/watcherdemo/upload/092e589a-53aa-4006-9b63-fa2f1f7dd998
2020-06-03T12:00:50.44-0500 [APP/PROC/WEB/0] OUT 2020-06-03 17:00:50.441  INFO 25 --- [       Thread-2] c.e.c.UploadWatcherService               : Event kind: ENTRY_CREATE | File affected: 092e589a-53aa-4006-9b63-fa2f1f7dd998

Observe the Filesystem

SSH into App Container

cf ssh cf-nfs-watchservice

Observe File Permissions

The mount point will be owned by nobody in the group root with permissions 700:

$ ls -l /var | grep watcherdemo
drwx------  3 nobody root  255 Jun  3 16:55 watcherdemo

The created upload directory will be owned by nobody in the group vcap with permissions 755:

$ ls -l /var/watcherdemo
drwxr-xr-x 2 nobody vcap 108 Jun  3 17:03 upload