7-Functions-Clients-oci-curl.md

Invoking oci-curl Configuration

In OCI you need to sign your requests to function http endpoints. Refer to OCI Signed Requests for more information and for sample clients in various popular languages.

One such client that OCI supports is Bash. oci-curl is a Bash function that which wraps curl and performs the required OCI request signing. It's useful and easy to configure so we'll quickly get it setup to see how it can be used to invoke a function.

1. Download the oci-curl Bash script to oci-curl.sh and open it in an editor (e.g., gedit).

2. Edit the file to include your account details which you can find in your ~/.oci/config file. Copy paste from the config file to the oci-curl.sh script.

   function oci-curl {
   
       # TODO: update these values to your own
       local tenancyId="";
       local authUserId="";
       local keyFingerprint="";
       local privateKeyPath="";

With the script updated with your credentials you can source it to define the oci-curl function in your Bash shell.

source oci-curl.sh

Function Invocation Endpoint

To invoke a function you'll need its "invoke endpoint" which can be obtained by inspecting the function using the fn inspect command. To inspect the "javafn" function you defined earlier, type the following:

fn inspect f labapp-NNN javafn

which will return a JSON object similar to the following:

{
	"annotations": {
		"fnproject.io/fn/invokeEndpoint": "https://k2kl7irx34a.us-phoenix-1.functions.oci.oraclecloud.com/20181201/functions/ocid1.fnfunc.oc1.us-phoenix-1.aaaaaaaaabzleh7l3ry7l2zpro6ddmgv3kwnwkn7xrtuxodtddsjbvwp3swa/actions/invoke",
		"oracle.com/oci/compartmentId": "ocid1.compartment.oc1..aaaaaaaaon25g3kisxyv4k54vvtrxadpbj2bbpetrpcacwax72uhmzpflyua"
	},
	"app_id": "ocid1.fnapp.oc1.us-phoenix-1.aaaaaaaaag4h7xotdzz27sp7z23ci6z4jqj4raq43ui6ouae5k2kl7irx34a",
	"created_at": "2019-04-02T21:56:55.812Z",
	"id": "ocid1.fnfunc.oc1.us-phoenix-1.aaaaaaaaabzleh7l3ry7l2zpro6ddmgv3kwnwkn7xrtuxodtddsjbvwp3swa",
	"idle_timeout": 30,
	"image": "phx.ocir.io/cloudnative-devrel/shsmith/javafn:0.0.2",
	"memory": 128,
	"name": "javafn",
	"timeout": 30,
	"updated_at": "2019-04-02T22:01:02.171Z"
}

If you look closely you can see there's an fnproject.io/fn/invokeEndpoint property buried in the JSON. You could copy/paste from here but there's a somewhat more convenient way to just get the invoke endpoint. You just add --endpoint to your ispect command:

fn inspect f --endpoint labapp-NNN javafn

which just returns the value of the fnproject.io/fn/invokeEndpoint property:

https://k2kl7irx34a.us-phoenix-1.functions.oci.oraclecloud.com/20181201/functions/ocid1.fnfunc.oc1.us-phoenix-1.aaaaaaaaabzleh7l3ry7l2zpro6ddmgv3kwnwkn7xrtuxodtddsjbvwp3swa/actions/invoke

Calling the Function with oci-curl

The syntax of oci-curl is not exactly like curl. To do a POST, which is the required invocation method for a function, it is:

oci-curl <hostname> post <payload file> <path>

This means you're going to have to extract the hostname and path elements from the url you obtained. In our example we have:

hostname=k2kl7irx34a.us-phoenix-1.functions.oci.oraclecloud.com path=/20181201/functions/ocid1.fnfunc.oc1.us-phoenix-1.aaaaaaaaabzleh7l3ry7l2zpro6ddmgv3kwnwkn7xrtuxodtddsjbvwp3swa/actions/invoke

NOTE: the "path" must begin with a /.

As mentioned above, you need to invoke a function with POST as you are passing a payload to your function for processing. oci-curl takes a payload via a file so let's create a file to pass. In a terminal you can create a payload.txt file by cating the text "Functions" into the it (closing with ctrl-d) or you can create and edit it using a text editor:

cat > payload.txt
Functions
^d

Now let's invoke the function. You'll need to use the host and path elements of your function endpoint, but using those from our example we'd have:

oci-curl k2kl7irx34a.us-phoenix-1.functions.oci.oraclecloud.com post payload.txt /20181201/functions/ocid1.fnfunc.oc1.us-phoenix-1.aaaaaaaaabzleh7l3ry7l2zpro6ddmgv3kwnwkn7xrtuxodtddsjbvwp3swa/actions/invoke

You'll be prompted for the passphrase for your private key, which is workshop.

Enter pass phrase for /home/demo/.oci/workshop_pri_key.pem

.pem: workshop

If all goes well you should see the output concatinating "Hello, " with the contents of the payload.txt file.

Hello, Functions

You've successfully invoked a function using a signed HTTP request using curl! Next we'll look how we can call functions from client code using the OCI SDK.

NEXT: Container as Function, UP: Labs, HOME: INDEX