https://github.com/abhirockzz/fn-go-sdk-invoke
Invoke Oracle Functions using the OCI Go SDK
https://github.com/abhirockzz/fn-go-sdk-invoke
faas go golang oracle-cloud-infrastructure oracle-functions orafunc-la serverless
Last synced: 3 months ago
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Invoke Oracle Functions using the OCI Go SDK
- Host: GitHub
- URL: https://github.com/abhirockzz/fn-go-sdk-invoke
- Owner: abhirockzz
- Created: 2019-02-26T05:38:24.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-05-28T10:51:47.000Z (about 6 years ago)
- Last Synced: 2023-08-20T07:22:14.430Z (almost 2 years ago)
- Topics: faas, go, golang, oracle-cloud-infrastructure, oracle-functions, orafunc-la, serverless
- Language: Go
- Homepage:
- Size: 34.2 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Invoke Oracle Functions using the OCI Go SDK
This example demonstrates how to invoke a function on Oracle Functions using (preview version of) the Oracle Cloud Infrastructure Go SDK.
## Introduction
To be specifc, it shows how you can invoke a function by its name given that you also provide the application name (to which the function belongs), the OCI compartment (for which your Oracle Functions service is configured) and the OCID of your tenancy
OCI SDK exposes two endpoints for Oracle Functions
- `functions.FunctionsManagementClient` - for CRUD operations e.g. creating applications, listing functions etc.
- `functions.FunctionsInvokeClient` - only required for invoking a function
along with a number of wrapper structs like `functions.FunctionSummary`,
`functions.ApplicationSummary`, and `identity.Compartment`.
The `invokeFunction` function in struct `FunctionsUtil` (`functions-util.go`) takes a `functions.FunctionSummary` for a
given function, the desired payload, and uses `functions.FunctionsInvokeClient` to
actually invoke the function. This seems relatively straightforward but
obtaining a `functions.FunctionSummary` requires navigating from the OCI compartment, to
the application, to the function. This involves multiple lookups (API calls).
To illustrate the steps, the `FunctionsUtils` struct provides a number of methods
that capture the steps required to navigate the OCI object model
- `getCompartment(compartmentName)` returns a Compartment with a given name
using `ListCompartments` function in `identity.IdentityClient` - it looks for compartments
in the tenancy with the provided name
- `getApplication(appName, compartment)` searches in the specified compartment
for the named application using the `ListApplications` function exposed by `functions.FunctionsManagementClient`
- `getFunction(funcName, application)` searches in the specified application for
the named function using `ListFunctions` in `functions.FunctionsManagementClient`.
The result is a `functions.FunctionSummary` object which provides the function ID, name,
and invoke endpoint
> The key thing to note here is that the function ID and its invoke endpoint will not change unless you delete the function (or the application it's a part of). As a result you do not need to repeat the above mentioned flow of API calls - the funtion ID and its invoke endpoint can be derived once and then **cached** in-memory (e.g. in a `map`) or an external data store
Once we have a `functions.FunctionSummary` (containing function OCID and invoke enpdoint)
at our disposal we can use the `invokeFunction(function,payload)` function in `FunctionsUtils` which:
- builds `functions.InvokeFunctionRequest` with the function OCID and the (optional) payload which we want to send to our function
- sets `functionsInvokeClient.Host` to the value of the invoke endpoint
- andn finally calls `invokeFunction` function in `functions.FunctionsInvokeClient` with the
`functions.InvokeFunctionRequest` returning the String response from the resulting
`functions.InvokeFunctionResponse` object
### Authentication
The client program needs to authenticate to OCI before being able to make service calls. The standard OCI authenitcation is used, which accepts the following inputs (details below) - tenant OCID, user OCID, fingerprint, private key and passphrase (optional). These details are required to instantiate a `common.ConfigurationProvider` using `common.NewRawConfigurationProvider` method and subsequently used by the service client objects (`functions.FunctionsInvokeClient`, `functions.FunctionsManagementClient`, `identity.IdentityClient`)
This example does not assume the presence of an OCI config file on the machine from where this is being executed. However, if you have one present as per the standard OCI practices i.e. a config file in your home directory, you can use `common.DefaultConfigProvider` for convenience
## Pre-requisites
1. Install latest Fn CLI -
`curl -LSs https://raw.githubusercontent.com/fnproject/cli/master/install | sh`
2. Create a function to invoke
Create a function using [Go Hello World Function](https://github.com/abhirockzz/oracle-functions-hello-worlds/blob/master/golang-hello-world.md)
### Install preview OCI Go SDK
You need to add the OCI Go SDK to your `GOPATH`
Set `GOPATH` environment variable
export GOPATH=
1. Back up your existing installation of OCI Go SDK and remove it from your `GOPATH`
2. Download and unzip the preview version of the OCI Go SDK
unzip [email protected]
3. Copy the preview SDK to your `GOPATH`
cp -R oci-go-sdk-preview@35505cb3d6a/ $GOPATH/src/github.com/oracle/oci-go-sdk
### Set environment variables
```shell
export TENANT_OCID=
export USER_OCID=
export PUBLIC_KEY_FINGERPRINT=
export PRIVATE_KEY_LOCATION=
```
> please note that `PASSPHRASE` is optional i.e. only required if your
> private key has one
```shell
export PASSPHRASE=
```
e.g.
```shell
export TENANT_OCID=ocid1.tenancy.oc1..aaaaaaaaydrjd77otncda2xn7qrv7l3hqnd3zxn2u4siwdhniibwfv4wwhtz
export USER_OCID=ocid1.user.oc1..aaaaaaaavz5efd7jwjjipbvm536plgylg7rfr53obvtghpi2vbg3qyrnrtfa
export PUBLIC_KEY_FINGERPRINT=42:42:5f:42:ca:a1:2e:58:d2:63:6a:af:42:d5:3d:42
export PRIVATE_KEY_LOCATION=/Users/foobar/oci_api_key.pem
```
> and only if your private key has a passphrase:
```shell
export PASSPHRASE=4242
```
## You can now invoke your function!
Clone this repository -
`git clone https://github.com/abhirockzz/fn-go-sdk-invoke`
Change to the correct directory where you cloned the example:
`go run src/*.go --compartmentName= --appName= --funcName= --invokePayload=<(optional) invokePayload>`
> Payload is optional. If your function doesn't expect any input parameters, you can omit `--invokePayload` argument
e.g. with payload:
`go run src/*.go --compartmentName=mycompartment --appName=helloworld-app --funcName=helloworld-go --invokePayload={\"name\":\"foobar\"}`
e.g. without payload:
`go run src/*.go --compartmentName=mycompartments --appName=helloworld-app --funcName=helloworld-go`
## What if my function needs input in binary form ?
This example demonstrates how to invoke a boilerplate function which accepts (an optional) string payload (JSON data). But, it is possible to send binary payload as well.
You can use this Tensorflow based function as an example to explore the possibility of invoking a function using binary content - https://github.com/abhirockzz/fn-hello-tensorflow. This function expects the image data (in binary form) as an input and returns what object that image resembles along with the percentage accuracy
If you were to deploy the above function and invoke it using Fn CLI, the command would something like this - `cat /home/foo/cat.jpeg | fn invoke fn-tensorflow-app classify`. In this case, the `cat.jpeg` image is being passed as an input to the function. The programmatic (using Go SDK) equivalent of this would look something like the below snippet, where the function invocation request (`functions.InvokeFunctionRequest`) is being built along with the binary input (image file content)
functionPayload, _ := os.Open("/home/foo/cat.jpeg") //error handling ignored for brevity
defer functionPayload.Close()
invokeFunctionReq := functions.InvokeFunctionRequest{FunctionId: functionID, InvokeFunctionBody: functionPayload}
Pay attention to the following line `functionPayload, _ := os.Open("/home/foo/cat.jpeg")`. The `InvokeFunctionBody` accepts an `io.ReadCloser` - as a result, it is possible to use `os.File` (or any other compatible type) as a function payload
## Troubleshooting
### If you fail to set the required environment variables like `TENANT_OCID` etc.
You will see the following error - `panic: Please set the environment variable TENANT_OCID`
### If you do not provide required arguments i.e. compartment name etc.
You will see the following error - `panic: Please set mandatory flag compartmentName`
### If you provide an invalid value for function name etc.
You will see something similar to - `panic: Could not find function myfunc in application myapp`
### If you provide an incorrect `TENANT_OCID` or `USER_OCID` or `PUBLIC_KEY_FINGERPRINT`
You will get this error - `Service error:NotAuthenticated. The required information to complete authentication was not provided or was incorrect.. http status code: 401. Opc request id: 4d7d76463a4f437361a1eb47815015d9/450D86C860C0592949AFF344C6DB17F0/84F3CCC7542175C08646CD4E213A2CEF`
### If your key has a passphrase but you fail to set the environment variable PASSPHRASE or provid an incorrect value
You will get this error - `panic: Could not instantiate Identity client - can not create client, bad configuration: x509: decryption password incorrect`