Develop Azure Functions

Question 1

What are the two things that functions contain in terms of development?

Answer 1

• code and config AKA functions.json
• compiled languages the config is generated automatically from annotations in code
• scripting languages you must provide the config file yourself

Question 2

What is functions.json?

Answer 2

• defines the functions trigger, binding and other config settings
• every function has 1 and only 1 trigger
• the runtime uses this config to determine the events to monitor and how to pass data into and out of a function execution

Question 3

What is the bindings property in functions.json?

Answer 3

• where you configure both triggers and bindings
• each binding shares a few common settings and some setting are specific to certain bindings
• Common settings are; type, direction and name

Question 4

What is a function app?

Answer 4

• provides an exeuction context in azure for which your functions run
• organises and collectively manages apps
• contains one or more functions that are managed, deployed and scaled together
• all functions in app share the same pricing plan, deployment method and runtime version

Question 5

What are some key files in a functions project?

Answer 5

• host.json file is in the root folder and contains runtime-specific config
• bin folder contains packages and other library files that the app requires

Question 6

How can we debug azure functions locally?

Answer 6

• can connect them directly to live azure services and use the local.settings.json file

Question 7

What is a function binding?

Answer 7

• a way of declaratively connecting another resource to the function
• can be input, output or both
• data from bindings is provided to the function as params
• they are optional, a function may have none or many

Question 8

What is the main advantage of triggers and bindings?

Answer 8

• let you avoid hardcoding access to other services

Question 9

How are trigger and bindings defined for different programming languages?

Answer 9

.NET uses decorating methods and params with C# attribs
JAVA uses decorating method and params with java annotations
- JS/Typescript/Python/PS uses the function.json schema

Question 10

What is the direction property?

Answer 10

• all triggers and bindings have this property in the functions.json file
• for triggers the direction is always in
• input and output bindings use in and out
• some bindings support inout

Question 11

How does a function project reference connection info?

Answer 11

• By name from its config provider
• doesn’t directly accept the connection details allowing them to be changed across environments
• the default config provider uses environment vars that are set in app settings when running in az functions service or from local settings file

Question 12

How do az functions utilize identities?

Answer 12

• can use ID instead of secret
• support depends on the extension using the connection
• in some cases a conn string may still be required in functions
• when hosted in az functions service ID based connections use a managed ID
• sysmtem-assigned ID is default but a user-assigned can be specified with credential and clientID properties
• when ran in local envs your dev ID is used instead

Question 13

What must identities have to use azure functions?

Answer 13

• must have permissions to perform the intended actions
• this is done by assigning an RBAC role or by specifying the ID in an access policy