VMware Cloud Assembly Custom Integration lessons learned

I’ve recently spent some time refactoring Sam McGeown’s Image as Code (IaC) Codestream pipeline for VMware vRealize Automation Cloud. The following details some of the lessons learned.

First off, I found the built in Code Stream REST tasks do not have a retry. I learned this the hard way when they had issues with their cloud offering last month. At times it would get a 500 error back when making a request, resulting in a failed execution.

This forced me to look at Python custom integrations which would retry until the correct success code was returned. I was able to get the pipeline working, but it did have a lot of repetitive code, lacked the ability to limit the number of retries, and was based on Python 2.

Seeing the error of my ways, I decided to again refactor the code with a custom module (For the repetitive code), and migrate to Python 3.

The original docker image was CentOS based and did not have Python 3 installed. Instead of just installing Python 3 thus increasing the size of the image, I opted to start with the Docker Official Python 3 image. I’ll get to the build file later.

Now on to the actual refactoring. Here I wanted to combine the reused code into a custom python module. My REST calls include POST (To get a Bearer Token), GET (With and without a Filter), PATCH (To update Image Mappings), and DELETE (To delete the test Image Profile and Cloud Template).

This module snippet includes PostBearerToken_session which returns the bearToken and other headers. GetFilteredVrac_sessions returns a filtered GET request. It also limits the retries to 5 attempts.

import requests
import logging
import os 
import json 
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry

# retry strategy to tolerate API errors.  Will retry if the status_forcelist matches.
retry_strategy = Retry (
    total=5,
    status_forcelist=[429, 500, 502, 503, 504],
    method_whitelist=["GET", "POST"],
    backoff_factor=2,
    raise_on_status=True,
)


adapter = HTTPAdapter(max_retries=retry_strategy)
https = requests.Session()
https.mount("https://", adapter)

vRacUrl = "https://api.mgmt.cloud.vmware.com"

def PostBearerToken_session(refreshToken):
    # Post to get the bearerToken from refreshToken
    # Will return the headers with Authorization populated
    # Build post payload 
    pl = {}
    pl['refreshToken'] = refreshToken.replace('\n', '')
    logging.info('payload is ' + json.dumps(pl))
    loginURL = vRacUrl + "/iaas/api/login"
    headers = {
        "Accept": "application/json",
        "Content-Type": "application/json"
        }
    r = https.post(loginURL, json=pl, headers=headers)
    responseJson = r.json()
    token = "Bearer " + responseJson["token"]
    headers['Authorization']=token
    return headers 

def GetFilteredVrac_sessions(requestUrl, headers, requestFilter):
    # Get a thing using a filter
    requestUrl = vRacUrl + requestUrl + requestFilter
    print(requestUrl)
    adapter = HTTPAdapter(max_retries=retry_strategy)
    https = requests.Session()
    https.mount("https://", adapter)
    r = https.get(requestUrl, headers=headers)
    responseJson = r.json()
    return responseJson

Here is the working Code Stream Custom Integration used to test this module. It will get the headers, then send a filtered request using the Cloud Account Name. It then pulls some information out of the Payload and prints it out. (Sorry for formatting).


 runtime: "python3"
 code: |
   import json 
   import requests
   import os 
   import sys
   import logging
 # append /build to the path
   # this is where the custom python module is copied to
   sys.path.append('/build')
   import vRAC
 # context.py is automatically added.
   from context import getInput, setOutput
   def main():
def main():
   refreshToken=getInput('RefreshToken')
   # now with new model
   # authHeaders will have all of the required headers, including the bearerToken
   authHeaders=vRAC.PostBearerToken_session(refreshToken)
   # test the getFunction with filter
   requestUrl = "/iaas/api/cloud-accounts"
   requestFilter = "?$filter=name eq '" + getInput('cloudAccountName') + "'" 
   # get the cloudAccount by name    
   cloudAccountJson=vRAC.GetFilteredVrac_sessions(requestUrl, authHeaders, requestFilter) 
   # get some specific data out for later
   cloudAccountId = cloudAccountJson['content'][0]['id']   
   logging.info('cloudAccountId: ' + cloudAccountId)
 if name == 'main':
       main()
 inputProperties:      # Enter fields for input section of a task
   # Password input
 - name: RefreshToken
   type: text
   title: vRAC Refresh Token
   placeHolder: 'secret/password field'
   defaultValue: changeMe
   required: true
   bindable: true
   labelMessage: vRAC RefreshToken 

 - name: cloudAccountName
   type: text 
   title: Cloud Account Name
   placeHolder: vc.corp.local
   defaultValue: vc.corp.local
   required: true
   bindable: true
   labelMessage: Cloud Account Name  

Next the new Docker image. This uses the official Python 3 image as a starting point. The build file copies everything over (Including the custom module and requirements.txt), then installs ‘requests’.

FROM python:3

WORKDIR /build

COPY . ./
RUN pip install --no-cache-dir -r requirements.txt

Now that the frame work is ready, it’s time to create the pipeline and test it. This is well documented here Creating and using pipelines in VMware Code Stream. Update the Host field with your predefined Docker Host, set the Builder image URL (Docker Hub repo and tag), and set the Working directory to ‘/build’ (to match WORKDIR in the Dockerfile).

Running the pipeline worked and returned the requested information.

This was a fairly brief article. I really just wanted to get everything written down before the weekend. I’ll have more in the near future.

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