Allow setting slog handler from env var

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added a flexible search filter UI for the job list. [PR #344](https://github.com/riverqueue/riverui/pull/344).
 - Added `riverlog` middleware logs to the job detail UI via a new unified attempts list, rather than separate lists for errors, attempted by, and now logs. [PR #346](https://github.com/riverqueue/riverui/pull/346).
 - Added a `RIVER_JOB_LIST_HIDE_ARGS_BY_DEFAULT` env and `ServerOpts.JobListHideArgsByDefault` setting to give the backend the ability to choose to hide args from the job list by default. This is useful if your args tend to be encoded or encrypted and not worth looking at in bulk. It can also be overridden in a new settings screen in the UI. [PR #354](https://github.com/riverqueue/riverui/pull/354).
+- Added a `RIVER_LOG_FORMAT` env which can be set to `json` to set the `riverui` executable to output JSON instead of `key=value` text. [PR #381](https://github.com/riverqueue/riverui/pull/381).
 
 ### Changed
 

cmd/riverui/main.go

@@ -25,7 +25,7 @@ import (
 func main() {
 	ctx := context.Background()
 
-	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+	logger := slog.New(getLogHandler(&slog.HandlerOptions{
 		Level: getLogLevel(),
 	}))
 
@@ -50,6 +50,16 @@ func envBooleanTrue(val string) bool {
 	return val == "1" || val == "true"
 }
 
+func getLogHandler(opts *slog.HandlerOptions) slog.Handler {
+	logFormat := strings.ToLower(os.Getenv("RIVER_LOG_FORMAT"))
+	switch logFormat {
+	case "json":
+		return slog.NewJSONHandler(os.Stdout, opts)
+	default:
+		return slog.NewTextHandler(os.Stdout, opts)
+	}
+}
+
 func getLogLevel() slog.Level {
 	if envBooleanTrue(os.Getenv("RIVER_DEBUG")) {
 		return slog.LevelDebug

docs/README.md

@@ -70,6 +70,8 @@ The `riverui` command utilizes the `RIVER_LOG_LEVEL` environment variable to con
 * `warn`
 * `error`
 
+By default logs are written with the [`slog.TextHandler`](https://pkg.go.dev/log/slog#TextHandler) `key=value` format. For JSON output with [`slog.JSONHandler`](https://pkg.go.dev/log/slog#JSONHandler), set `RIVER_LOG_FORMAT=json`.
+
 ## Development
 
 See [developing River UI](./development.md).