feat: use human-readable log format for local CLI commands (#2806)

* feat: use human-readable log format for local CLI commands

Coglet defaults to JSON structured logs for production (GKE/Stackdriver
compatibility), but this makes local development output hard to read.

Set LOG_FORMAT=console in cog serve, cog run, cog predict, and cog train
so developers see human-readable logs locally. Production is unaffected
since the env var is only set by the CLI for local commands.

* Update pkg/predict/predictor.go

Co-authored-by: ask-bonk[bot] <249159057+ask-bonk[bot]@users.noreply.github.com>
Signed-off-by: Mark Phelps <209477+markphelps@users.noreply.github.com>

* chore: appease the linter

Signed-off-by: Mark Phelps <mphelps@cloudflare.com>

---------

Signed-off-by: Mark Phelps <209477+markphelps@users.noreply.github.com>
Signed-off-by: Mark Phelps <mphelps@cloudflare.com>
Co-authored-by: Mark Phelps <209477+markphelps@users.noreply.github.com>
Co-authored-by: ask-bonk[bot] <249159057+ask-bonk[bot]@users.noreply.github.com>
Co-authored-by: Mark Phelps <mphelps@cloudflare.com>
Co-authored-by: asahoo <anishsahoo2005@gmail.com>

Author: 4 people

pkg/cli/exec.go

@@ -99,8 +99,12 @@ func execCmd(cmd *cobra.Command, args []string) error {
 		gpus = "all"
 	}
 
+	// Use human-readable log format for local development
+	env := make([]string, len(envFlags))
+	copy(env, envFlags)
+	env = append(env, "LOG_FORMAT=console")
+
 	// Automatically propagate RUST_LOG for Rust coglet debugging
-	env := envFlags
 	if rustLog := os.Getenv("RUST_LOG"); rustLog != "" {
 		env = append(env, "RUST_LOG="+rustLog)
 	}

pkg/cli/serve.go

@@ -115,8 +115,12 @@ func cmdServe(cmd *cobra.Command, arg []string) error {
 		args = append(args, "--upload-url", uploadURL)
 	}
 
+	// Use human-readable log format for local development
+	env := make([]string, len(envFlags))
+	copy(env, envFlags)
+	env = append(env, "LOG_FORMAT=console")
+
 	// Automatically propagate RUST_LOG for Rust coglet debugging
-	env := envFlags
 	if rustLog := os.Getenv("RUST_LOG"); rustLog != "" {
 		env = append(env, "RUST_LOG="+rustLog)
 	}

pkg/predict/predictor.go

@@ -82,12 +82,19 @@ type Predictor struct {
 // NewPredictor constructs a Predictor. See PredictorOptions for the
 // meaning of each field.
 func NewPredictor(_ context.Context, opts PredictorOptions) (*Predictor, error) {
+	// Use human-readable log format for local development
+	env := make([]string, len(opts.RunOptions.Env))
+	copy(env, opts.RunOptions.Env)
+	env = append(env, "LOG_FORMAT=console")
+
 	if global.Debug {
-		opts.RunOptions.Env = append(opts.RunOptions.Env, "COG_LOG_LEVEL=debug")
+		env = append(env, "COG_LOG_LEVEL=debug")
 	} else {
-		opts.RunOptions.Env = append(opts.RunOptions.Env, "COG_LOG_LEVEL=warning")
+		env = append(env, "COG_LOG_LEVEL=warning")
 	}
 
+	opts.RunOptions.Env = env
+
 	return &Predictor{
 		runOptions:    opts.RunOptions,
 		isTrain:       opts.IsTrain,