elsa-workflows/elsa-core · error · JsonException

The console log stream filter must be 'stdout', 'stderr'…

Error message

The console log stream filter must be 'stdout', 'stderr', or null.

What it means

ConsoleStreamJsonConverter.Read deserializes a ConsoleStream? value in JSON. Only null tokens, valid strings (stdout/stderr/all), and integers mapping to defined ConsoleStream values are accepted; any other JSON token type (object, array, true/false, StartObject, etc.) produces this JsonException.

Solutions

1. Change the JSON payload so the stream field is "stdout", "stderr", "all", or null
2. Ensure numbers are sent as plain integers, not strings/objects
3. Fix the client-side serializer to emit the scalar enum value

Example fix

// before
{ "stream": { "name": "stdout" } }
// after
{ "stream": "stdout" }

bool IsValidStreamFilter(object? v) => v is null or string { } s && s is "" or "all" or "stdout" or "stderr" or int i && Enum.IsDefined(typeof(ConsoleStream), i);

bool IsScalarStream(object? v) => v is null or string or int or long;

try { filter = JsonSerializer.Deserialize<ElsaConsoleLogFilter>(payload); }
catch (JsonException ex) when (ex.Message.Contains("console log stream filter"))
{ filter = new ElsaConsoleLogFilter(); /* default */ }

When it happens

Trigger: POSTing or deserializing a console log stream filter where the stream field is a JSON object, array, boolean, or nested structure instead of a string or number.

Common situations: Sending {"stream": {"$eq": "stdout"}} from an over-engineered client; frontend passing a boolean flag; a client sending a nested filter object where a scalar is expected.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Cannot deserialize to .
• Failed to deserialize
• The binding to activity type
• Expected number or string.
• Cannot convert to bool

AI-assisted analysis of elsa-workflows/elsa-core@fe9217bdfa (2026-09-13). Data as JSON: /api/errors/0dfb6b93056678c3. Report an issue: GitHub.

Appendix: source

Thrown at src/modules/Elsa.Diagnostics.ConsoleLogs/Contracts/ConsoleStreamJsonConverter.cs:18

using System.Text.Json;
using System.Text.Json.Serialization;

namespace Elsa.Diagnostics.ConsoleLogs.Contracts;

/// <summary>
/// Converts the public console stream filter contract values.
/// </summary>
public sealed class ConsoleStreamJsonConverter : JsonConverter<ConsoleStream?>
{
    public override ConsoleStream? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return reader.TokenType switch
        {
            JsonTokenType.Null => null,
            JsonTokenType.String => ReadString(reader.GetString()),
            JsonTokenType.Number => ReadNumber(ref reader),
            _ => throw new JsonException("The console log stream filter must be 'stdout', 'stderr', or null.")
        };
    }

    public override void Write(Utf8JsonWriter writer, ConsoleStream? value, JsonSerializerOptions options)
    {
        if (value == null)
        {
            writer.WriteNullValue();
            return;
        }

        writer.WriteStringValue(value.Value switch
        {
            ConsoleStream.Stdout => "stdout",
            ConsoleStream.Stderr => "stderr",
            _ => throw new JsonException($"Unsupported console stream value '{value}'.")
        });
    }

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