feat(looker): propagate client IP from incoming MCP requests to downstream SDK calls by pushkar0108 · Pull Request #3253 · googleapis/mcp-toolbox

pushkar0108 · 2026-05-19T13:59:52Z

Description

Propagates the original client's IP address from incoming MCP requests (HTTP/SSE) down to downstream Looker SDK API calls. Extracts IP from incoming headers (X-Forwarded-For or X-Real-IP), stores it in context, and injects X-Forwarded-For and X-Real-IP headers in the Looker SDK's HTTP transport client. Updates all Looker tool interfaces and mock sources to accept context.Context accordingly. Adds a robust, mock-backed unit test verifying header injection.

PR Checklist

🛠️ Fixes #3263

gemini-code-assist

Code Review

This pull request implements client IP propagation for Looker tools by introducing utility functions to extract and manage IPs within the context. The Looker source transport was updated to include these IPs in outgoing headers, and all associated tools were refactored to support context-aware SDK initialization. Review feedback suggests making the IP extraction logic more robust against malformed headers and ensuring the RoundTripper implementation clones requests to avoid side effects on the original object.

…tream SDK calls Propagates the original client's IP address from incoming MCP requests (HTTP/SSE) down to downstream Looker SDK API calls. Extracts IP from incoming headers (X-Forwarded-For or X-Real-IP), stores it in context, and injects X-Forwarded-For and X-Real-IP headers in the Looker SDK's HTTP transport client. Updates all Looker tool interfaces and mock sources to accept context.Context accordingly. Adds a robust, mock-backed unit test verifying header injection.

pushkar0108

Tested the changes and now we are able to receive the actual client IP.

drstrangelooker · 2026-05-21T14:26:07Z

/gcbrun

drstrangelooker · 2026-05-21T14:46:48Z

Lint failed.

run golangci-lint
  Running [/home/runner/golangci-lint-2.12.2-linux-amd64/golangci-lint config path] in [/home/runner/work/mcp-toolbox/mcp-toolbox] ...
  Running [/home/runner/golangci-lint-2.12.2-linux-amd64/golangci-lint config verify] in [/home/runner/work/mcp-toolbox/mcp-toolbox] ...
  Running [/home/runner/golangci-lint-2.12.2-linux-amd64/golangci-lint run  --timeout 10m] in [/home/runner/work/mcp-toolbox/mcp-toolbox] ...
  Error: internal/sources/looker/looker_test.go:134:10: Error return value of `w.Write` is not checked (errcheck)
  		w.Write([]byte(`{"id": 123}`))
  		       ^
  1 issues:
  * errcheck: 1

drstrangelooker · 2026-05-21T16:39:08Z

/gcbrun

drstrangelooker · 2026-05-21T16:55:51Z

/gcbrun

drstrangelooker · 2026-05-21T17:15:11Z

/gcbrun

Yuan325 · 2026-05-21T18:09:42Z

/gcbrun

Yuan325 · 2026-05-21T18:44:20Z

/gcbrun

🤖 I have created a release *beep* *boop* --- ## [1.3.0](v1.2.0...v1.3.0) (2026-05-21) ### Features * **auth:** Implement MCP auth tool-level scopes validation ([#3049](#3049)) ([c528985](c528985)) * **looker:** Propagate client IP from incoming MCP requests to downstream SDK calls ([#3253](#3253)) ([75da6c2](75da6c2)) * Setup SQLCommenter and allow client metadata ([#3064](#3064)) ([9f1f9b3](9f1f9b3)) * **tool/cloudsqladmin:** Add `cloud-sql-admin-execute-sql-many` and `cloud-sql-admin-sql-many` ([#3083](#3083)) ([ef300a8](ef300a8)) ### Bug Fixes * **auth/generic:** Fix generic auth expiration field and integration with `authRequired` ([#3251](#3251)) ([f4d16c0](f4d16c0)) * Enforce toolset/promptset boundary on tools/call and prompts/get ([#3036](#3036)) ([c739b80](c739b80)) * **tools/http:** Prevent path traversal and base path scope escape ([#3218](#3218)) ([80a6602](80a6602)) * **tools/looker:** Return a 401 error to MCP client when Looker returns a 401 ([#3233](#3233)) ([4f409a3](4f409a3)) * **tools/looker:** Strip wrapping quotes from filter values for unquoted parameters ([#3273](#3273)) ([1e3de96](1e3de96)) * **tools:** Initialize query result slices to empty array ([#3250](#3250)) ([60ddf48](60ddf48)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com> Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com>

🤖 I have created a release *beep* *boop* --- ## [1.3.0](v1.2.0...v1.3.0) (2026-05-21) ### Features * **auth:** Implement MCP auth tool-level scopes validation ([#3049](#3049)) ([c528985](c528985)) * **looker:** Propagate client IP from incoming MCP requests to downstream SDK calls ([#3253](#3253)) ([75da6c2](75da6c2)) * Setup SQLCommenter and allow client metadata ([#3064](#3064)) ([9f1f9b3](9f1f9b3)) * **tool/cloudsqladmin:** Add `cloud-sql-admin-execute-sql-many` and `cloud-sql-admin-sql-many` ([#3083](#3083)) ([ef300a8](ef300a8)) ### Bug Fixes * **auth/generic:** Fix generic auth expiration field and integration with `authRequired` ([#3251](#3251)) ([f4d16c0](f4d16c0)) * Enforce toolset/promptset boundary on tools/call and prompts/get ([#3036](#3036)) ([c739b80](c739b80)) * **tools/http:** Prevent path traversal and base path scope escape ([#3218](#3218)) ([80a6602](80a6602)) * **tools/looker:** Return a 401 error to MCP client when Looker returns a 401 ([#3233](#3233)) ([4f409a3](4f409a3)) * **tools/looker:** Strip wrapping quotes from filter values for unquoted parameters ([#3273](#3273)) ([1e3de96](1e3de96)) * **tools:** Initialize query result slices to empty array ([#3250](#3250)) ([60ddf48](60ddf48)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com> Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com> b001006

🤖 I have created a release *beep* *boop* --- ## [1.3.0](googleapis/mcp-toolbox@v1.2.0...v1.3.0) (2026-05-21) ### Features * **auth:** Implement MCP auth tool-level scopes validation ([googleapis#3049](googleapis#3049)) ([c528985](googleapis@c528985)) * **looker:** Propagate client IP from incoming MCP requests to downstream SDK calls ([googleapis#3253](googleapis#3253)) ([75da6c2](googleapis@75da6c2)) * Setup SQLCommenter and allow client metadata ([googleapis#3064](googleapis#3064)) ([9f1f9b3](googleapis@9f1f9b3)) * **tool/cloudsqladmin:** Add `cloud-sql-admin-execute-sql-many` and `cloud-sql-admin-sql-many` ([googleapis#3083](googleapis#3083)) ([ef300a8](googleapis@ef300a8)) ### Bug Fixes * **auth/generic:** Fix generic auth expiration field and integration with `authRequired` ([googleapis#3251](googleapis#3251)) ([f4d16c0](googleapis@f4d16c0)) * Enforce toolset/promptset boundary on tools/call and prompts/get ([googleapis#3036](googleapis#3036)) ([c739b80](googleapis@c739b80)) * **tools/http:** Prevent path traversal and base path scope escape ([googleapis#3218](googleapis#3218)) ([80a6602](googleapis@80a6602)) * **tools/looker:** Return a 401 error to MCP client when Looker returns a 401 ([googleapis#3233](googleapis#3233)) ([4f409a3](googleapis@4f409a3)) * **tools/looker:** Strip wrapping quotes from filter values for unquoted parameters ([googleapis#3273](googleapis#3273)) ([1e3de96](googleapis@1e3de96)) * **tools:** Initialize query result slices to empty array ([googleapis#3250](googleapis#3250)) ([60ddf48](googleapis@60ddf48)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com> Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com> b001006

pushkar0108 requested review from a team as code owners May 19, 2026 13:59

blunderbuss-gcf Bot assigned Yuan325 May 19, 2026

gemini-code-assist Bot reviewed May 19, 2026

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Comment thread internal/sources/looker/looker.go

Comment thread internal/util/util.go

Yuan325 marked this pull request as draft May 19, 2026 15:13

pushkar0108 force-pushed the feat/sources-looker-client-ip branch from fe1df1f to 2c8a1bf Compare May 20, 2026 10:08

Merge branch 'googleapis:main' into feat/sources-looker-client-ip

e361f82

pushkar0108 commented May 20, 2026

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pushkar0108 marked this pull request as ready for review May 20, 2026 10:13

Merge branch 'main' into feat/sources-looker-client-ip

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drstrangelooker approved these changes May 21, 2026

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Merge branch 'main' into feat/sources-looker-client-ip

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drstrangelooker added 2 commits May 21, 2026 12:46

Merge branch 'main' into feat/sources-looker-client-ip

2e741f0

fixed lint issue

ed82297

Merge branch 'main' into feat/sources-looker-client-ip

faf6e25

drstrangelooker enabled auto-merge (squash) May 21, 2026 17:15

Yuan325 approved these changes May 21, 2026

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Comment thread .gitignore Outdated

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Merge branch 'main' into feat/sources-looker-client-ip

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drstrangelooker merged commit 75da6c2 into googleapis:main May 21, 2026
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release-please Bot mentioned this pull request May 21, 2026

chore(main): release 1.3.0 #3228

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BrewTestBot mentioned this pull request May 21, 2026

mcp-toolbox 1.3.0 Homebrew/homebrew-core#284130

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feat(looker): propagate client IP from incoming MCP requests to downstream SDK calls#3253

feat(looker): propagate client IP from incoming MCP requests to downstream SDK calls#3253
drstrangelooker merged 9 commits into
googleapis:mainfrom
pushkar0108:feat/sources-looker-client-ip

pushkar0108 commented May 19, 2026 •

edited

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pushkar0108 commented May 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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pushkar0108 commented May 19, 2026 •

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