Configuration Summary

Resolved configuration is reported once, not one record per key. What that looks like depends on who is reading. On an interactive terminal the summary is a tree, ending with the address the listener accepted:

   .-.   .-.
 .(   ) (   ).    Popcorn Web v0.1.0
(   o     o   )   started at 2026-07-27 23:31:04 JST
(    \___/    )   env dev · config.dev.toml
 '-.__.___.__-'

configuration
├─ middleware
│  ├─ access_log       true
│  ├─ compression      true  ← file
│  └─ request_timeout  0s
├─ server
│  ├─ port          8080
│  └─ read_timeout  30s
└─ session
   └─ enabled  false

listening on http://localhost:8080

Only values that came from somewhere other than the built-in defaults are marked: ← file, ← env, or ← flag.

The last line is the address the listener accepted, which is not always the server.port above it: a development run moves off a port it cannot bind, and the summary keeps both — what was configured, and what answers. See pw dev.

Everywhere else — a pipe, a container, a log collector — the same facts become one structured record instead, so a JSON handler or an OpenTelemetry bridge ships a single event rather than sixty:

{"time":"2026-07-27T23:31:04+09:00","level":"INFO","msg":"popcornweb started",
 "environment":"dev","config_file":"config.dev.toml",
 "listening":"http://localhost:8080",
 "config":{"server":{"port":"8080"},"session":{"enabled":"false"}},
 "config_source":{"middleware.compression":"file"}}

observability.boot_log overrides the choice:

Value	Behavior
auto (default)	tree on a terminal, one record otherwise
tree	always the tree, written to stderr
record	always one record through the default slog logger
off	no startup summary

When the application owns the listener — pw.Middlewares instead of pw.Run — the summary is emitted after initialization, without the listening line.

Restarts under pw dev

Once per process is once per rebuild in the developer loop, and reprinting forty lines because you saved a template pushes whatever you were reading off the screen. So pw dev reads the summary its application printed and reports the next one against it. A restart that resolved to the same configuration says so and stops:

reloaded

A restart that resolved to something else shows the rows that moved, in the section they came from:

└─ html
   └─ bot_async_timeout  5s → 10s  ← file

A key that appeared or went away is marked ← added or ← removed, which is what turning html.bot_detection off looks like: the settings it gates leave the report entirely. A key whose value survived a change of layer reads ← default → env, because where a value came from is reported for the same reason the value is. The listening address, the environment, the config file, and the framework version are compared beside the keys, so a run that moved off a port it could not bind is one line rather than silence.

The first summary of a session is printed whole — nothing has been read yet, so there is no shorter answer that is still true. record and off are untouched: a collector deduplicates, and a developer who turned the summary off did not ask for a reload line in its place.

Secrets in logs

Sensitive values are masked in both formats. Ordinary values become *****; a DSN retains its public location while its credentials and query string are removed. The exact name-matching rule and the explicit secret overrides are documented under what the startup summary shows.

See Application Configuration for where these values come from, and Slow Query Diagnostics for the same idea applied to SQL.