cftunnel

cftunnel

What?

It's nothing special whatsoever, just a tiny app with the sole purpose of providing a bridge for accessing back end services in Cloud Foundry just as if they were locally hosted.

For instance this allows us to connect fully featured UI tools like MySQL Workbench to a MySQL service instance residing inside Cloud Foundry. Without this bridging technique, we're restricted to the using the MySQL CLI tool.

Why?

Because ...

• cf create-service-key is just a way of inspecting fragments of what would appear inside the VCAP_SERVICES environment variable should we ever happen to physically bind an app to a service.

• Our real business apps are supposed to be immutable so what business do we have hijacking a cf ssh call just to interfere with the port mappings inside our container?

• Basically, these instructions feel a little bit heavy-handed.

Instead, let's have a pointless, tiny NodeJS web app for arbitrary service bindings which is specifically designed for cf ssh port bind hijacks.

How?

Assuming you're already logged onto PWS or a PCF instance, you can use the following instructions:

git clone https://github.com/pivotal-education/public-tools.git
cd public-tools/cftunnel && cf push   # NOTE we're using a CF manifest file
cf create-service cleardb spark mysql # replace "cleardb spark" with "p-mysql 100mb" when targeting PCF
cf bind-service cftunnel mysql
cf env cftunnel                       # NOTE the VCAP_SERVICES JSON object value

From the VCAP_SERVICES environment variable you can identify cleardb (or p-mysql) values for name, hostname, port, username and password within the JSON object. NOTE name indicates the identifier of the database Cloud Foundry generated for you.

Now we can use cf ssh to hijack (or leech off) the cftunnel app, thereby bridging the internal and external networks and exposing the underlying service instance on a local port.

# for example, if port is 3306 then localport could be a related 
# high-order port such as 63306 to avoid local port collisions
cf ssh -L [localport]:[hostname]:[port] cftunnel

You'll know this call worked if you get back a vcap@xyz command prompt. Don't exit from this prompt whilst you need access to the underlying service.

Assuming you're using this for MySQL, fire up MySQL Workbench and connect to the localhost using the values you identified from the earlier call you made to cf env cftunnel.

Task Complete!