microsoft/aspire · error · ArgumentException

Unknown file system entry type

Error message

Unknown file system entry type

What it means

Thrown while converting a DCP container file-system entry (file, OpenSSL certificate, or directory) into its serialized ContainerFileSystemEntry form. The switch expects only the three known entry types; any other ContainerFileSystemEntry implementation triggers this ArgumentException, indicating an internal model invariant was violated.

Solutions

1. Add a new case to the switch in ToContainerFileSystemEntry mapping the new entry type to a ContainerFileSystemEntryType.
2. If you did not intend a custom type, verify which object is being passed and use one of the supported entry classes (ContainerFile, ContainerOpenSSLCertificateFile, ContainerDirectory).
3. Update any associated DCP schema handling so the new entry type round-trips correctly.

Example fix

// before
_ => throw new ArgumentException("Unknown file system entry type")
// after
ContainerVolumeSecret => ContainerFileSystemEntryType.Secret,
_ => throw new ArgumentException($"Unknown file system entry type: {item.GetType().Name}")

if (entry is not (ContainerFile or ContainerOpenSSLCertificateFile or ContainerDirectory))
    throw new NotSupportedException($"{entry.GetType().Name} is not a supported container file entry.");

static bool IsKnownEntryType(ContainerFileSystemEntry e) => e is ContainerFile or ContainerOpenSSLCertificateFile or ContainerDirectory;

When it happens

Trigger: Calling ToContainerFileSystemEntry with a ContainerFileSystemEntry-derived type that is not ContainerFile, ContainerOpenSSLCertificateFile, or ContainerDirectory — effectively only possible by introducing a new DCP model type without updating this converter.

Common situations: Developers extending the DCP model with a new file-entry kind (e.g. a new certificate type) and forgetting to add the mapping case; not reachable through normal public Aspire APIs.

Related errors

• Container tunnel service
• Could not generate a unique name for service
• Custom container networks are not supported yet.
• Expected an ContainerExec resource, but got
• Service ' ' refers to endpoint ' ' that does not exist

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/f7dde4c28f8cb972. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting/Dcp/Model/Container.cs:385

        return Destination == other.Destination
            && DefaultOwner == other.DefaultOwner
            && DefaultGroup == other.DefaultGroup
            && Umask == other.Umask
            && (Entries ?? Enumerable.Empty<ContainerFileSystemEntry>()).SequenceEqual(other.Entries ?? Enumerable.Empty<ContainerFileSystemEntry>());
    }
}

internal static class ContainerFileSystemItemExtensions
{
    [AspireExportIgnore(Reason = "Internal conversion to the DCP ContainerFileSystemEntry model, which is not part of the ATS surface.")]
    public static ContainerFileSystemEntry ToContainerFileSystemEntry(this ContainerFileSystemItem item)
    {
        var type = item switch
        {
            ContainerFile => ContainerFileSystemEntryType.File,
            ContainerOpenSSLCertificateFile => ContainerFileSystemEntryType.OpenSSL,
            ContainerDirectory => ContainerFileSystemEntryType.Directory,
            _ => throw new ArgumentException("Unknown file system entry type")
        };

        var entry = new ContainerFileSystemEntry
        {
            Type = type,
            Name = item.Name,
            Owner = item.Owner,
            Group = item.Group,
            Mode = (int)item.Mode,
        };

        if (item is ContainerFileBase file)
        {
            entry.Source = file.SourcePath;
            entry.Contents = file.Contents;
            entry.ContinueOnError = file.ContinueOnError;

            if (file.Contents is not null && file.SourcePath is not null)

View on GitHub (pinned to 25830f84bd)