Handling failed http requests with bearer token having lease time

[schwibach]

Hey,

I'm trying to make some flows more robust and efficient.

I have a flow that runs at a specific time every day and loops through up to 1000 iterations.

For each iteration, I'm making API calls against a REST API, retrieving a bearer token and then making the api call.

The tokens have a lease time of 3 minutes, so it would be more efficient, if I create two variables (one for the token and one for the ticks when it was created / I have 10 different endpoints, so it will be more like 20 variables) and then have each iteration check if more than 2:40 have passed since the creation of the token and refresh the variables only if needed.

Now, my issue is: if the second HTTP action (the actual call I want to make) fails, I want it to check again if too much time has passed. So, the retry policy in Power Automate doesn't cut it.

My questions are: How would you solve the token refresh on server errors in the API and do you think working with variables is a good idea, or should I just store the values in a SharePoint list without worrying about the 10 different servers?

[PabloRoldan · Accepted solution]

How would you solve the token refresh on server errors in the API and do you think working with variables is a good idea, yes it is, but hard to maintain you can create a JSON variable that handles all the tokens, if I understand correctly  each endpoint uses different token so you could try something like this

{
"token1":{
"timeStamp":"2024-03-25T17:41:12.9793837Z",
"token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZC...."
},
"token2":{
"timeStamp":"2024-03-25T17:41:12.9793837Z",
"token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZC...."
}
}

you can get the ticks comparing with dateDifference() utcNow() and with timeStamp Property, you can also edit that JSON with a compose action using setProperty FX function, 

I'll go by get token, store token, validate if timeStamp is < a 3 min if true call API, maybe you could create a child flow,

the Http that uses the token I'd set the retry policy None, and I will know that it fail because the token if the response is either 401 | 403, then add parallel branch that Runs After Failed http request and if body http has 

statusCode 401 | 403 add that request payload to a queue or array within the flow to tried them again

(you could use childflow)

[schwibach]

Thanks. That gave me some very good ideas. I think I will use an object variable instead of the text variables.
I'll have to manage adding the properties for each tenant/server at the start of the flow and then updating them.

Right now, I'm thinking that I won't use a child flow,.
My current design idea: "do until"-loop with a max counter of 5 and if I get a response 200, it will set the counter to 6, if I get an error, it will increase the counter by 1.