fix(storage): honor MINIO_PUBLIC_URL for browser-facing object URLs

[Osamaali313]

Description

Stored screenshots/files never load on any deployment where MinIO is not reachable at localhost:9000 from the browser (reverse proxy, separate host, or a non-default public port).

Root cause

In server/src/storage/mino.ts, the browser-facing object URL written to a run's binaryOutput was composed from the internal MinIO host/port:

const publicHost = process.env.MINIO_PUBLIC_HOST || 'http://localhost';
const publicPort = process.env.MINIO_PORT || '9000';
const publicUrl = `${publicHost}:${publicPort}/${this.bucketName}/${minioKey}`;

MINIO_PORT is the internal MinIO port used for the minio client connection, and the host defaults to localhost. So in a typical Docker/proxied deploy the generated URLs point at localhost:9000 (or force :9000 onto a proxied host like https://storage.example.com:9000/...), which the browser cannot reach — the screenshots silently 404. This matches the report in #832.

Fix

Prefer a complete public base URL via a new optional MINIO_PUBLIC_URL, and only fall back to the existing MINIO_PUBLIC_HOST:MINIO_PORT composition when it is not set:

const publicBase = (
  process.env.MINIO_PUBLIC_URL
    ? process.env.MINIO_PUBLIC_URL
    : `${process.env.MINIO_PUBLIC_HOST || 'http://localhost'}:${process.env.MINIO_PORT || '9000'}`
).replace(/\/+$/, '');
const publicUrl = `${publicBase}/${this.bucketName}/${minioKey}`;

• Non-breaking: with no new env var set, the output is byte-for-byte identical to before (verified for the default and MINIO_PUBLIC_HOST+MINIO_PORT cases).
• Deployments behind a proxy can now set MINIO_PUBLIC_URL=https://storage.example.com and get correct, reachable URLs (no internal port appended).
• Documents the variable in ENVEXAMPLE.

Fixes #832

Testing

No automated test suite exists in the repo, so I verified the URL-building logic in isolation across cases:

Env	Output
(default)	http://localhost:9000/<bucket>/<key> (unchanged)
MINIO_PUBLIC_HOST=http://1.2.3.4, MINIO_PORT=9000	http://1.2.3.4:9000/<bucket>/<key> (unchanged)
MINIO_PUBLIC_URL=https://storage.example.com	https://storage.example.com/<bucket>/<key> (fixed)
MINIO_PUBLIC_URL=https://storage.example.com/	trailing slash stripped → correct

Summary by CodeRabbit

• New Features

  • MinIO now supports optional configurable public URL setting, enabling reverse-proxy and non-localhost deployment scenarios
  • System automatically falls back to default host/port configuration when custom URL is not provided

• Documentation

  • Added configuration documentation and setup instructions for MinIO public URL deployments

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 66fb957c-8939-447d-9269-b3c18e23214d

📥 Commits

Reviewing files that changed from the base of the PR and between 50ee9b3 and 755e768.

📒 Files selected for processing (2)

• ENVEXAMPLE
• server/src/storage/mino.ts

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Walkthrough

This PR enables configurable MinIO public URLs in self-hosted deployments behind reverse proxies. The ENVEXAMPLE file documents the new optional MINIO_PUBLIC_URL setting, and server/src/storage/mino.ts updates binary output URL construction to prefer MINIO_PUBLIC_URL when available, falling back to host/port composition.

Changes

MinIO Public URL Configuration

Layer / File(s)	Summary
MinIO public URL configuration and implementation ENVEXAMPLE, server/src/storage/mino.ts	Environment variable documentation for MINIO_PUBLIC_URL guides reverse-proxy deployments. Service implementation in BinaryOutputService.uploadAndStoreBinaryOutput constructs browser-facing URLs using the environment variable (trimmed of trailing slashes) or falls back to the host/port composition.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested labels

Scope: Documentation

Poem

🐰 A proxy stands between the cloud and thee,
MinIO URLs now roam wild and free,
No more locked to localhost's cage,
Configure your domain on this glorious page!
Screenshots soar where they should be. ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and accurately summarizes the main change: honoring a new MINIO_PUBLIC_URL configuration for constructing browser-facing object URLs, which is the core fix in the PR.
Linked Issues check	✅ Passed	The PR implements the fix for issue #832 by introducing MINIO_PUBLIC_URL support, allowing deployments to configure public-facing MinIO URLs so screenshots display correctly in distributed setups.
Out of Scope Changes check	✅ Passed	All changes are scoped to resolving the linked issue: ENVEXAMPLE documents the new setting, and minio.ts implements the URL construction logic with fallback behavior.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds support for a configurable browser-facing MinIO base URL to avoid generating unreachable localhost:9000 links in proxied/non-default deployments.

Changes:

• Build public object URLs from MINIO_PUBLIC_URL when set, with fallback to MINIO_PUBLIC_HOST + MINIO_PORT.
• Trim trailing slashes from the configured public base before concatenating path segments.
• Document the new MINIO_PUBLIC_URL variable in ENVEXAMPLE.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
server/src/storage/mino.ts	Prefer a fully specified public base URL for generated object links, with normalization and fallback behavior.
ENVEXAMPLE	Documents MINIO_PUBLIC_URL for reverse-proxy/public-endpoint setups.

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[amhsirak]

@Osamaali313 lgtm - thanks! 🙌