Replace Gunicorn with Granian to improve pgAdmin 4 performance

[Smartappli]

This change proposes replacing Gunicorn with Granian as the application server for pgAdmin 4 in order to improve overall performance, scalability, and efficiency.

Granian offers a modern Rust-based runtime with strong ASGI/WSGI support, lower overhead, and better concurrency handling compared to Gunicorn. For pgAdmin 4, this could lead to:

• improved request throughput,
• reduced response latency,
• better resource utilization,
• and improved behavior under concurrent workloads.

The goal of this change is to modernize the deployment stack while maintaining compatibility with the existing pgAdmin 4 application architecture.

Further benchmarking and validation may be required to confirm gains across different deployment environments.

Summary by CodeRabbit

• Chores
  • Migrated from Gunicorn to Granian as the application server in the Docker container, improving performance and compatibility
  • Updated server binding configuration to support both socket and TCP modes
  • Simplified Docker build by removing Gunicorn-specific configuration dependencies

[coderabbitai]

Walkthrough

The changes replace the Gunicorn application server with Granian in the PgAdmin Docker setup. The Dockerfile now installs granian==2.7.2 instead of gunicorn==23.0.0 and copies only run_pgadmin.py into the image. The entrypoint script is refactored to use Granian's CLI arguments instead of Gunicorn's, and the dedicated Gunicorn configuration file is removed.

Changes

Cohort / File(s)	Summary
Docker Build Configuration Dockerfile	Replaced gunicorn==23.0.0 Python dependency with granian==2.7.2; removed copying of pkg/docker/gunicorn_config.py to /pgadmin4/.
Application Server Startup pkg/docker/entrypoint.sh	Refactored startup logic to use Granian's CLI arguments (--interface wsgi --workers 1 --blocking-threads) in place of Gunicorn arguments; changed bind address construction from single BIND_ADDRESS to BIND_ARGS (supporting both Unix socket --uds and TCP --host --port modes); converted access logging logic to use --access-log / --no-access-log flags; updated TLS configuration to use --ssl-keyfile / --ssl-certificate; replaced server command from gunicorn to granian.
Server Configuration pkg/docker/gunicorn_config.py	Entire file deleted; removed Gunicorn-specific configuration including SERVER_SOFTWARE override, logger configuration, and JSON logging setup.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Optimized Dockerfile #9378: Modifies Dockerfile's handling of runtime files and dependency installation, including COPY instructions for pkg/docker/run_pgadmin.py and related packages.
• Corrected erroneous comment in Dockerfile #9488: Updates Dockerfile's COPY instructions, potentially affecting the same Docker build steps and runtime file consolidation.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately reflects the main change: replacing Gunicorn with Granian in the Docker runtime for pgAdmin 4 performance improvements, which is the primary objective across all modified files.
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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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (2)

pkg/docker/entrypoint.sh (2)

204-204: Environment variable naming: Consider documenting backward compatibility.

The script retains GUNICORN_THREADS and GUNICORN_ACCESS_LOGFILE environment variable names for backward compatibility, which is good. However, users may be confused by Gunicorn-prefixed variables when running Granian.

Consider adding a comment explaining this is for backward compatibility, or adding support for new GRANIAN_* aliases in the future.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@pkg/docker/entrypoint.sh` at line 204, Add a short inline comment above the
exec line explaining that GUNICORN_* vars (e.g., GUNICORN_THREADS and
GUNICORN_ACCESS_LOGFILE) are kept for backward compatibility when running
Granian, and optionally add support for GRanian-prefixed aliases by reading
GRANIAN_THREADS and GRANIAN_ACCESS_LOGFILE (fallback to GUNICORN_* if unset)
before composing ACCESS_LOG_ARGS, TLS_ARGS, and BIND_ARGS so users can use
either naming convention.

---

141-143: Stale comment references Gunicorn.

The comment on line 141 still mentions "Gunicorn" but the server has been changed to Granian.

📝 Suggested fix

-    # Initialize DB before starting Gunicorn
+    # Initialize DB before starting Granian
     # Importing pgadmin4 (from this script) is enough
     /venv/bin/python3 run_pgadmin.py

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@pkg/docker/entrypoint.sh` around lines 141 - 143, Update the stale comment
that mentions "Gunicorn" to reference the current server "Granian" instead;
locate the comment above the run_pgadmin.py invocation (the line commenting DB
initialization) and change the wording from "Initialize DB before starting
Gunicorn" to something like "Initialize DB before starting Granian" so the
comment matches the actual server being used.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@pkg/docker/entrypoint.sh`:
- Around line 192-196: The current branch only enables access logs when
GUNICORN_ACCESS_LOGFILE equals "-" which breaks support for file paths; update
the logic around the GUNICORN_ACCESS_LOGFILE check so it handles three cases:
"-" -> set ACCESS_LOG_ARGS to enable logging to stdout (e.g., "--access-log"),
empty/unset -> set ACCESS_LOG_ARGS to disable access logging (e.g.,
"--no-access-log"), and any other non-empty value -> treat it as a file path by
setting ACCESS_LOG_ARGS to the flag that enables logging to a file (e.g.,
including the file path) and emit a warning via the existing logger/echo
indicating a custom file path is being used; reference the
GUNICORN_ACCESS_LOGFILE env var and ACCESS_LOG_ARGS variable when making this
change.

---

Nitpick comments:
In `@pkg/docker/entrypoint.sh`:
- Line 204: Add a short inline comment above the exec line explaining that
GUNICORN_* vars (e.g., GUNICORN_THREADS and GUNICORN_ACCESS_LOGFILE) are kept
for backward compatibility when running Granian, and optionally add support for
GRanian-prefixed aliases by reading GRANIAN_THREADS and GRANIAN_ACCESS_LOGFILE
(fallback to GUNICORN_* if unset) before composing ACCESS_LOG_ARGS, TLS_ARGS,
and BIND_ARGS so users can use either naming convention.
- Around line 141-143: Update the stale comment that mentions "Gunicorn" to
reference the current server "Granian" instead; locate the comment above the
run_pgadmin.py invocation (the line commenting DB initialization) and change the
wording from "Initialize DB before starting Gunicorn" to something like
"Initialize DB before starting Granian" so the comment matches the actual server
being used.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 60c8a8bb-2fcb-494b-8259-8f4f362199d9

📥 Commits

Reviewing files that changed from the base of the PR and between 2576548 and 0138ee9.

📒 Files selected for processing (3)

• Dockerfile
• pkg/docker/entrypoint.sh
• pkg/docker/gunicorn_config.py

💤 Files with no reviewable changes (1)

• pkg/docker/gunicorn_config.py