R2 Outage Toggle

R2 Outage Toggle

Modifies s3_management/manage_v2.py to disable or re-enable Cloudflare R2 (download-r2.pytorch.org) URL generation for PyTorch foundation packages. Use during R2 outages to fall back to S3/CloudFront, or to restore R2 usage after an outage is resolved.

When to use this skill

Use when the user asks to:

• Disable R2 / turn off R2 / stop using download-r2.pytorch.org
• Re-enable R2 / turn on R2 / restore R2 usage
• Handle an R2 outage or Cloudflare outage
• Switch nightly or prod packages away from R2
• Fall back to S3/CloudFront for foundation packages

Target file

s3_management/manage_v2.py (relative to repo root)

Key data structures

There are two sets that control which packages use R2 URLs:

| Set | Purpose | Location |

|-----|---------|----------|

| PT_R2_PACKAGES | Packages using R2 for nightly builds (whl/nightly) | ~line 437 |

| PT_R2_PACKAGES_PROD | Packages using R2 for prod/stable builds (not test, not nightly) | ~line 452 |

Both sets contain members of PT_FOUNDATION_PACKAGES. The URL routing logic is in the to_simple_package_html method (~line 799-824).

Instructions

Step 1: Determine the action and scope

Ask the user (if not already clear) two things:

• Action: disable R2 or re-enable R2?
• Scope: nightly only, prod only, or both?

Step 2: Read the current state

Read s3_management/manage_v2.py and check the current contents of PT_R2_PACKAGES and PT_R2_PACKAGES_PROD. They may already be empty (disabled) or populated (enabled).

Step 3a: To DISABLE R2

To disable R2, empty the relevant set(s) while preserving a comment showing the original contents. This ensures easy re-enablement.

Disable R2 for nightly — Replace the PT_R2_PACKAGES set with an empty set:

# Packages that should use R2 (download-r2.pytorch.org) for nightly builds
# These packages will have their URLs point to R2 instead of S3/CloudFront
# when the path is whl/nightly
# R2 DISABLED - original packages commented out during R2 outage:
# "torch", "torchvision", "torchaudio", "fbgemm_gpu", "fbgemm_gpu_genai",
# "triton", "pytorch_triton", "pytorch_triton_rocm", "pytorch_triton_xpu"
PT_R2_PACKAGES: set[str] = set()

Disable R2 for prod — Replace the PT_R2_PACKAGES_PROD set with an empty set:

# Packages that should use R2 (download-r2.pytorch.org) for prod/stable builds
# These packages will have their URLs point to R2 instead of S3/CloudFront
# when the path is NOT whl/test and NOT whl/nightly (i.e., prod)
# R2 DISABLED - original packages commented out during R2 outage:
# "torchaudio", "fbgemm_gpu", "fbgemm_gpu_genai"
PT_R2_PACKAGES_PROD: set[str] = set()

Step 3b: To RE-ENABLE R2

Restore the original set contents and remove the outage comments.

Re-enable R2 for nightly — Restore PT_R2_PACKAGES:

# Packages that should use R2 (download-r2.pytorch.org) for nightly builds
# These packages will have their URLs point to R2 instead of S3/CloudFront
# when the path is whl/nightly
PT_R2_PACKAGES = {
    "torch",
    "torchvision",
    "torchaudio",
    "fbgemm_gpu",
    "fbgemm_gpu_genai",
    "triton",
    "pytorch_triton",
    "pytorch_triton_rocm",
    "pytorch_triton_xpu",
}

Re-enable R2 for prod — Restore PT_R2_PACKAGES_PROD:

# Packages that should use R2 (download-r2.pytorch.org) for prod/stable builds
# These packages will have their URLs point to R2 instead of S3/CloudFront
# when the path is NOT whl/test and NOT whl/nightly (i.e., prod)
PT_R2_PACKAGES_PROD = {
    "torchaudio",
    "fbgemm_gpu",
    "fbgemm_gpu_genai",
}

Step 4: Verify the change

After editing, read back the modified sections to confirm correctness. Also verify that:

• The to_simple_package_html method logic (~line 799-824) was NOT modified — it naturally handles empty sets correctly (no packages will match, so R2 URLs won't be generated).
• No other references to PT_R2_PACKAGES or PT_R2_PACKAGES_PROD were affected.

Step 5: Remind about deployment

After making the change, remind the user:

> Important: This change only modifies the source file. To take effect, you need to:

> 1. Commit and land this change

> 2. Re-run the index generation: python s3_management/manage_v2.py all

> (or target specific prefixes like whl/nightly or whl depending on scope)

>

> The index HTML files will be regenerated with S3/CloudFront URLs (relative URLs for foundation packages) instead of download-r2.pytorch.org URLs.

How it works

The URL routing in to_simple_package_html checks package membership in these sets:

if package_name.lower() in PT_R2_PACKAGES and resolved_subdir.startswith("whl/nightly"):
    base_url = "https://download-r2.pytorch.org"
elif package_name.lower() in PT_R2_PACKAGES_PROD and not test and not nightly:
    base_url = "https://download-r2.pytorch.org"
elif use_cloudfront_for_non_foundation and package not in PT_FOUNDATION_PACKAGES:
    base_url = "https://d21usjoq99fcb9.cloudfront.net"
else:
    base_url = ""  # relative URL (served from S3)

When the sets are empty, no package matches the R2 conditions, so foundation packages fall through to base_url = "" (relative URLs served from S3). This is the safe fallback during an R2 outage.

Example usage

Disable R2 for everything during an outage:

R2 is down, disable R2 for both nightly and prod

Disable R2 for nightly only:

Turn off R2 for nightly builds

Re-enable after outage is resolved:

R2 outage is over, re-enable R2 for nightly and prod