fix(backend): replace honoLogger with pino-based HTTP logger

[test3207]

Summary

Replace Hono's default honoLogger() middleware with a custom pino-based HTTP logger to output structured JSON logs.

Problem

The default honoLogger() outputs human-readable text format:

<-- GET /health
--> GET /health 200 2ms

This cannot be parsed by Grafana/Loki in production environments.

Solution

Created a custom HTTP logger middleware that uses the existing pino logger:

• Outputs structured JSON with method, path, status, duration, traceId
• Uses source: "http.request" and col1: "http" for log categorization
• Development: pino-pretty renders human-readable output
• Production: Raw JSON for Loki/Grafana parsing

Example Output

Development (pino-pretty):

[2025-12-28 19:34:05.092 +0800] INFO: GET /health 200 2ms
    service: "m3w-backend"
    source: "http.request"
    method: "GET"
    path: "/health"
    status: 200
    duration: 2
    traceId: "9577c11c-d242-4a41-a89a-8c4a73efe85a"

Production (JSON):

{"level":30,"time":1735389245092,"service":"m3w-backend","method":"GET","path":"/health","status":200,"duration":2,"traceId":"..."}

Changes

• backend/src/lib/http-logger.ts - New HTTP logger middleware
• backend/src/index.ts - Replace honoLogger() with custom middleware

Testing

• npm test passes
• Manual verification: HTTP requests logged in structured format
• traceId properly generated and included

Closes #274

[Copilot]

Pull request overview

This PR replaces Hono's default text-based logger middleware with a custom pino-based HTTP logger that outputs structured JSON logs suitable for parsing by Grafana/Loki in production environments. The implementation integrates with the existing trace middleware to include traceIds in HTTP request logs.

Key changes:

• Created a new HTTP logger middleware using the existing pino logger infrastructure
• Replaced honoLogger() with httpLogger() in the middleware chain
• Logs include structured fields (method, path, status, duration, traceId) for observability

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
backend/src/lib/http-logger.ts	New HTTP logger middleware that wraps requests and logs them with structured pino output, including status-based log levels
backend/src/index.ts	Removed Hono's default logger import and replaced with custom httpLogger middleware

[github-actions]

Coverage after merging fix/http-logger-json-format into main will be

72.72%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
	100%	100%	100%	100%
src/lib
events.ts	100%	100%	100%	100%
logger-client.ts	35.65%	28.77%	48.48%	39.86%	101, 101, 101, 101, 101–104, 115, 120, 120–121, 121, 121, 125, 129, 205, 212–214, 214, 214–215, 221, 221, 221–222, 222, 222–223, 225, 247, 252, 257, 257, 257, 259, 259, 259, 261, 263, 263, 263–266, 266, 266, 272, 272, 272–274, 276, 288, 291–292, 292, 292–293, 295, 295, 295, 295–296, 296, 296–297, 301, 307, 307, 311, 311–312, 312–313, 313–314, 314–315, 315–316, 316, 323–324, 324, 324–325, 330, 330, 330, 332–334, 340, 340, 340–341, 344, 363–364, 371–372, 375–376, 381, 383–384, 389, 391–392, 411, 411, 411–414, 418, 426, 426, 426, 430, 437, 440–441, 441, 441, 447–448, 448, 448, 454–455, 455, 455, 460, 460, 460, 462–463, 466, 466, 469, 472–473, 476, 476, 54–56, 56, 56, 61, 61, 61–62, 66, 66, 66, 69–70, 72, 72, 72, 74, 74, 74, 74, 74, 74–77, 80, 80, 80–83, 87–88, 88, 88–90, 93–94
shared.ts	100%	100%	100%	100%
src/lib/api
config.ts	75%	62.50%	100%	85.71%	17, 22, 22–23
src/lib/audio
media-session.ts	75.16%	90.91%	71.43%	65.91%	109–110, 143, 156–158, 165–167, 169, 176–178, 180, 188–190, 192, 199–201, 203, 219, 233, 247, 260, 268–269, 282, 44–45, 78, 88–89, 95
queue.ts	86.15%	82.54%	92%	86.92%	210–211, 223, 225, 225, 225–226, 228, 249–252, 303, 313, 313, 313–314, 316, 37–38, 54–55, 72, 76–77
src/lib/offline-proxy/routes
libraries.ts	42.23%	24.32%	57.14%	51.69%	127–128, 213, 253, 266–268, 271, 273, 273, 273–274, 283, 283, 283, 283, 283–284, 293–294, 296, 296, 296–297, 301, 304–305, 308, 310, 310, 310, 312, 316, 316–317, 317, 321, 325, 328, 331, 331, 331–332, 343, 346, 349, 349, 349, 349, 349–350, 352, 357, 361, 364, 366, 369, 369–370, 370–371, 371–372, 372–373, 373–374, 374, 374, 374–375, 375–376, 376, 378, 378, 378, 378, 381, 381, 393–394, 397, 402, 402, 402–404, 404, 410, 420–421, 427–430, 430, 430, 432, 434, 434, 434, 434, 434–435, 445, 448, 450, 455, 66, 95, 95–96
player.ts	47.26%	35%	57.14%	55.70%	102, 138, 150–151, 154, 159, 161, 165, 167, 167, 167–169, 171, 171, 171–172, 180, 180–181, 181, 195, 200–201, 207–208, 208, 208–209, 217, 217–218, 218, 231, 236, 259, 280–283, 294, 306–309, 311, 313, 313, 313–314, 314, 314–315, 315, 315–316, 316, 316, 320, 322, 327, 57–59, 59, 59, 59, 59–60, 64–65, 72, 74, 94
playlists.ts	86.27%	92.31%	91.67%	84.35%	102, 121, 138, 155, 175, 189, 195–196, 215, 228, 234, 59, 65–70, 72, 89
songs.ts	90.48%	75%	100%	95.24%	104, 106, 113, 115, 143–144
src/lib/offline-proxy/utils
auth.ts	93.33%	100%	100%	89.47%	70–71
index.ts	100%	100%	100%	100%
sorting.ts	100%	100%	100%	100%
src/lib/storage
storage-constants.ts	100%	100%	100%	100%
src/lib/utils
audio-filter.ts	100%	100%	100%	100%
defaults.ts	100%	100%	100%	100%
format-duration.ts	100%	100%	100%	100%
format.ts	100%	100%	100%	100%
hash.ts	88.24%	100%	100%	85.19%	62–63, 84–85
uuid.ts	90%	87.50%	83.33%	93.75%	31–32
src/locales
i18n.ts	95.45%	87.50%	100%	97.37%	23, 40–41