Environment variables are not loaded in Azure Pipelines

[danciudev]

Describe the bug

It seems that it isn't loading the environment variables

This bug happened again a few months ago in version 7.1.x—I don't remember exactly which one, but it was fixed, and then it came back

• script: pnpm run build
  displayName: "Build frontend (${{ parameters.environment }})"
  env:
  NODE_OPTIONS: "--max-old-space-size=4096"
  CI: true
  LEFTHOOK: "false"
  VITE_DEPLOYMENT_ENV: ${{ parameters.environment }}
  VITE_AZURE_AD_CLIENT_ID: $(azureAdClientId)
  VITE_AZURE_AD_AUTHORITY: $(azureAdAuthority)

Reproduction

Steps to reproduce

No response

System Info

Linux CI, in local is working

Used Package Manager

pnpm

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[manimovassagh]

This is almost certainly an Azure Pipelines variable expansion issue rather than a Vite bug.

In Azure Pipelines YAML, $(variableName) is macro syntax that gets expanded at pipeline compile time. If the variable is defined as a secret or comes from a variable group, it might not be available at the stage where the expansion happens, resulting in the literal string $(azureAdClientId) being passed instead of the actual value.

A few things to check:

1. Use the env mapping with runtime syntax instead of macro syntax:

- script: pnpm run build
  displayName: "Build frontend"
  env:
    VITE_AZURE_AD_CLIENT_ID: $(azureAdClientId)
    VITE_AZURE_AD_AUTHORITY: $(azureAdAuthority)

If azureAdClientId is a secret variable, $(azureAdClientId) in env: should still work. But confirm the variable is actually defined in the scope of that job/stage.

2. Debug by printing the env (temporarily, remove after):

- script: |
    echo "VITE_DEPLOYMENT_ENV=$VITE_DEPLOYMENT_ENV"
    echo "VITE_AZURE_AD_CLIENT_ID length: ${#VITE_AZURE_AD_CLIENT_ID}"
    pnpm run build
  env:
    VITE_DEPLOYMENT_ENV: ${{ parameters.environment }}
    VITE_AZURE_AD_CLIENT_ID: $(azureAdClientId)
    VITE_AZURE_AD_AUTHORITY: $(azureAdAuthority)

Don't echo the actual value of secrets, but printing the length tells you if it's empty.

3. Check your Vite version for the env loading regression. There was a known regression in Vite 7.1.x around .env file loading order. If you're on a specific patch, try updating to the latest 8.x or pin to a known-good version.

4. Verify envPrefix in your vite.config — the default is VITE_, but if something overrides it, your VITE_* vars won't be picked up.

5. Make sure the variables aren't being consumed at import.meta.env level vs process.env level. Vite replaces import.meta.env.VITE_* at build time using static replacement. If the env var isn't set when vite build runs, it'll be replaced with undefined.

The fact that it works locally but not in CI strongly suggests the env vars simply aren't reaching the build process. Start with the debug step above to confirm.

[chrisjcthomas]

The Vite docs make two things relevant here:

1. only variables with the VITE_ prefix are exposed to client code
2. environment variables that already exist when Vite starts take priority over .env files

So if these values are really present in the process environment when vite build starts:

env:
  VITE_DEPLOYMENT_ENV: ...
  VITE_AZURE_AD_CLIENT_ID: ...
  VITE_AZURE_AD_AUTHORITY: ...

then Vite should expose them.

That makes this look more like a CI/env injection problem than a Vite env-loading problem.

The quickest checks I would make are:

• confirm the variables are actually present in the build step environment
• confirm you're reading them as import.meta.env.VITE_*
• confirm envPrefix was not customized away from VITE_

So my read is: if local works and CI does not, the likely issue is that Azure Pipelines is not passing the variables into the vite build process the way you expect, not that Vite is refusing to load VITE_* vars in CI.