fix: add 1MB size limit on deployment logs with truncation (closes #122)

Cap AppendLog at 1MB, truncating oldest lines when exceeded. Prevents
unbounded SQLite database growth from long-running builds.

internal/models/deployment.go

@@ -5,6 +5,7 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"strings"
 	"time"
 
 	"git.eeqj.de/sneak/upaas/internal/database"
@@ -76,7 +77,11 @@ func (d *Deployment) Reload(ctx context.Context) error {
 	return d.scan(row)
 }
 
+// maxLogSize is the maximum size of deployment logs stored in the database (1MB).
+const maxLogSize = 1 << 20
+
 // AppendLog appends a log line to the deployment logs.
+// If the total log size exceeds maxLogSize, the oldest lines are truncated.
 func (d *Deployment) AppendLog(ctx context.Context, line string) error {
 	var currentLogs string
 
@@ -84,7 +89,22 @@ func (d *Deployment) AppendLog(ctx context.Context, line string) error {
 		currentLogs = d.Logs.String
 	}
 
-	d.Logs = sql.NullString{String: currentLogs + line + "\n", Valid: true}
+	newLogs := currentLogs + line + "\n"
+
+	if len(newLogs) > maxLogSize {
+		// Keep the most recent logs that fit within the limit.
+		// Find a newline after the truncation point to avoid partial lines.
+		truncateAt := len(newLogs) - maxLogSize
+		idx := strings.Index(newLogs[truncateAt:], "\n")
+
+		if idx >= 0 {
+			newLogs = "[earlier logs truncated]\n" + newLogs[truncateAt+idx+1:]
+		} else {
+			newLogs = "[earlier logs truncated]\n" + newLogs[truncateAt:]
+		}
+	}
+
+	d.Logs = sql.NullString{String: newLogs, Valid: true}
 
 	return d.Save(ctx)
 }