winglang/wing

Confusion around `util.env` and `util.tryEnv` in preflight vs inflight contexts

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#4,601 opened on Oct 19, 2023

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good first issue🎨 sdk🐶 dogfood

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Description

The util.env and util.tryEnv utilities work differently in preflight and inflight contexts.

Given the following example:

MY_VAR=123 wing compile main.w

// main.w
bring cloud;
bring util;

log(util.env("MY_VAR")); // Logs 123
let MY_VAR = util.env("MY_VAR");

new cloud.Function(inflight () => {
  log(util.tryEnv("MY_VAR") ?? "<no value>"); // Logs <no value>
  log(MY_VAR); // Logs 123
});

The Cloud Function util.tryEnv is being translated into a lookup to process.env rather than use the host's environment variables. I find this behaviour confusing, maybe even unnecessary. Do we need to access environment variables in inflight functions? The only environment variables we can specify are when invoking the Wing CLI.

IMO, log(util.tryEnv("MY_VAR") ?? "<no value>"); should log 123 as well, with the actual inflight code being inlined as log("123" ?? "<no value>"); (it could even be simplified to log("123")).

Contributor guide

Research direction
Investigate how environment variables are captured in preflight and passed to inflight contexts. Look at the compiler's handling of `util.env` and `util.tryEnv` in the Wing compiler source code.
Tech stack
typescript
Domain
backendcloud
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
WingTypeScriptGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65