[miniflare] Add environment variables to control cf.json fetching by petebacondarwin · Pull Request #12469 · cloudflare/workers-sdk

petebacondarwin · 2026-02-07T14:27:32Z

Adds two new environment variables that allow users to control the cf.json caching behavior in Miniflare:

CLOUDFLARE_CF_FETCH_ENABLED: Set to "false" to disable fetching entirely and use fallback Request.cf data. No files are created in node_modules/.mf/. Defaults to "true".
CLOUDFLARE_CF_FETCH_PATH: Set to a custom path to use a different location for caching the cf.json file instead of the default node_modules/.mf/cf.json. An empty value uses the default path.

The explicit cf option in Miniflare takes precedence over both environment variables.

This is particularly useful for:

Non-JavaScript projects (e.g., Rust, C++, Go Workers) that don't want a node_modules directory created automatically
Multi-project setups where users want consistent global configuration
Projects wanting custom cache locations

Example usage:

# Disable cf fetching for all projects
export CLOUDFLARE_CF_FETCH_ENABLED=false
npx wrangler dev

# Or use a custom cache location
export CLOUDFLARE_CF_FETCH_PATH=/tmp/.cf-cache.json
npx wrangler dev

Tests
- Tests included/updated
- Automated tests not possible - manual testing has been completed as follows:
- Additional testing not necessary because:
Public documentation
- Cloudflare docs PR(s):
- Documentation not necessary because: The environment variables are self-documenting and the changeset provides usage examples.

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changeset-bot · 2026-02-07T14:27:47Z

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Latest commit: 814d321

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claude · 2026-02-07T14:27:58Z

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The changeset .changeset/add-wrangler-cf-fetch-env.md passes all validation criteria:

✅ Version Type: minor is appropriate for new configuration options
✅ Changelog Quality: Clear description with helpful usage examples showing how to use the new environment variables
✅ Markdown Headers: No h1/h2/h3 headers used
✅ Analytics: No new analytics collection
✅ Dependabot: Not a dependency update
✅ Experimental Features: These are stable features, properly documented

The changeset follows best practices with a clear title, detailed explanation of the new environment variables, and practical examples showing real-world usage scenarios.

pkg-pr-new · 2026-02-07T14:32:10Z

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@12469

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@12469

miniflare

npm i https://pkg.pr.new/miniflare@12469

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@12469

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@12469

@cloudflare/vite-plugin

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@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@12469

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@12469

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@12469

wrangler

npm i https://pkg.pr.new/wrangler@12469

commit: 814d321

devin-ai-integration

✅ Devin Review: No Issues Found

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NuroDev

Overall looks good. One question though:

Explicit cf option in Miniflare: Takes precedence over the environment variable.

Is this normal? I have always assumed that if an environment variable exists to modify how a feature functions that that will always be the highest level of override, no? The same as if there is an experimental feature hard coded to now be enabled by default and there was an env var to disable it, enabling / using that env var would disable it and override the hard coded default.

petebacondarwin · 2026-02-07T16:57:09Z

I have always assumed that if an environment variable exists to modify how a feature functions that that will always be the highest level of override, no?

I think we normally go with: CLI arg -> env var -> config file -> default

In this case the "explicit cf option" is part of the Miniflare programmatic API, which I think equates to the CLI args when in programmatic usage.

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packages/miniflare/src/cf.ts

petebacondarwin · 2026-02-07T17:26:00Z

@NuroDev - implementation changed PTAL

…ironment variables Add documentation for two new environment variables that control cf.json fetching behavior in Miniflare: - CLOUDFLARE_CF_FETCH_ENABLED: disable cf.json fetching entirely - CLOUDFLARE_CF_FETCH_PATH: use a custom cache location for cf.json Updates both the system environment variables reference page and the Miniflare get-started guide. Related: cloudflare/workers-sdk#12469 Co-Authored-By: pbacondarwin@cloudflare.com <pete@bacondarwin.com>

devin-ai-integration

Devin Review found 1 new potential issue.

View 7 additional findings in Devin Review.

packages/workers-utils/src/environment-variables/misc-variables.ts

Adds two new environment variables that allow users to control the cf.json caching behavior in Miniflare: - CLOUDFLARE_CF_FETCH_ENABLED: Set to "false" or "0" to disable fetching entirely (uses fallback data). Defaults to "true". - CLOUDFLARE_CF_FETCH_PATH: Set to a custom path to use a different location for caching the cf.json file. Empty string is treated as unset. This is useful for non-JavaScript projects (like Rust or Go Workers) that don't want a node_modules directory created automatically. Fixes #3659

workers-devprod added this to workers-sdk Feb 7, 2026

github-project-automation bot moved this to Untriaged in workers-sdk Feb 7, 2026

petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from 9abc10d to 9a9e66d Compare February 7, 2026 15:00

petebacondarwin changed the title ~~[miniflare] Add WRANGLER_CF_FETCH environment variable to control cf.json fetching~~ [miniflare] Add CLOUDFLARE_CF_FETCH environment variable to control cf.json fetching Feb 7, 2026

petebacondarwin marked this pull request as ready for review February 7, 2026 15:12

petebacondarwin requested a review from a team as a code owner February 7, 2026 15:12

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petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from 9a9e66d to aba7873 Compare February 7, 2026 17:05

petebacondarwin changed the title ~~[miniflare] Add CLOUDFLARE_CF_FETCH environment variable to control cf.json fetching~~ [miniflare] Add environment variables to control cf.json fetching Feb 7, 2026

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packages/miniflare/src/cf.ts Show resolved Hide resolved

petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from aba7873 to 3f613d6 Compare February 7, 2026 17:13

petebacondarwin mentioned this pull request Feb 7, 2026

Document CLOUDFLARE_CF_FETCH_ENABLED and CLOUDFLARE_CF_FETCH_PATH environment variables cloudflare/cloudflare-docs#28174

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petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from 3f613d6 to 84af6d4 Compare February 8, 2026 14:11

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petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from 84af6d4 to 5f7234d Compare February 8, 2026 14:34

petebacondarwin force-pushed the fix/3659-cf-fetch-env-var branch from 5f7234d to 814d321 Compare February 8, 2026 14:36

petebacondarwin merged commit 2d90127 into main Feb 8, 2026
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petebacondarwin deleted the fix/3659-cf-fetch-env-var branch February 8, 2026 15:08

github-project-automation bot moved this from Approved to Done in workers-sdk Feb 8, 2026

workers-devprod mentioned this pull request Feb 8, 2026

Version Packages #12427

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[miniflare] Add environment variables to control cf.json fetching#12469

[miniflare] Add environment variables to control cf.json fetching#12469
petebacondarwin merged 1 commit intomainfrom
fix/3659-cf-fetch-env-var

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