Struct Config 

pub struct Config {

    pub config_version: u32,
    pub default_model: String,
    pub models_dir: String,
    pub server_port: u16,
    pub default_width: u32,
    pub default_height: u32,
    pub default_steps: u32,
    pub embed_metadata: bool,
    pub t5_variant: Option<String>,
    pub qwen3_variant: Option<String>,
    pub output_dir: Option<String>,
    pub media_roots: Option<Vec<String>>,
    pub default_negative_prompt: Option<String>,
    pub expand: ExpandSettings,
    pub logging: LoggingConfig,
    pub runpod: RunPodSettings,
    pub lambda: LambdaSettings,
    pub gpus: Option<Vec<usize>>,
    pub queue_size: Option<usize>,
    pub models: HashMap<String, ModelConfig>,
}

Fields

config_version: u32

Config schema version for migrations. Old configs without this field default to 0 and are migrated on first load.

default_model: String

models_dir: String

server_port: u16

default_width: u32

default_height: u32

default_steps: u32

embed_metadata: bool

t5_variant: Option<String>

Preferred T5 encoder variant: “fp16” (default), “q8”, “q6”, “q5”, “q4”, “q3”, or “auto”. “auto” selects the best variant that fits in GPU VRAM. An explicit quantized tag always uses that variant regardless of VRAM.

qwen3_variant: Option<String>

Preferred Qwen3 text encoder variant: “bf16” (default), “q8”, “q6”, “iq4”, “q3”, or “auto”. “auto” selects the best variant that fits in GPU VRAM (with drop-and-reload).

output_dir: Option<String>

Directory to persist generated images. Default: ~/.mold/output/. Override with MOLD_OUTPUT_DIR env var. Set to empty string to disable (TUI gallery will not function when disabled).

media_roots: Option<Vec<String>>

Allow roots for trusted server-local media request paths. Override with MOLD_MEDIA_ROOTS using the platform path-list separator.

default_negative_prompt: Option<String>

Global default negative prompt for CFG-based models (SD1.5, SDXL, SD3, Wuerstchen). Overridden by per-model negative_prompt or CLI --negative-prompt.

expand: ExpandSettings

Prompt expansion settings.

logging: LoggingConfig

Logging configuration.

runpod: RunPodSettings

RunPod integration settings (api key, defaults, auto-teardown behaviour).

lambda: LambdaSettings

Lambda Cloud integration settings.

gpus: Option<Vec<usize>>

GPU ordinals to use (None = all available).

queue_size: Option<usize>

Max queued requests before 503 (default: 200).

models: HashMap<String, ModelConfig>

Per-model configurations, keyed by model name.

Implementations

impl Config

pub fn gpu_selection(&self) -> GpuSelection

Build a GpuSelection from the config’s gpus field.

pub fn queue_size(&self) -> usize

Return the configured queue size or the default (200).

pub fn install_runtime_models_dir_override(models_dir: PathBuf)

pub fn load_or_default() -> Self

pub fn reload_from_disk_preserving_runtime(&self) -> Self

Reload config from disk while preserving runtime-only overrides.

pub fn mold_dir() -> Option<PathBuf>

The root mold directory. Resolution: MOLD_HOME env var → ~/.mold/ → ./.mold (if HOME unset).

pub fn config_path() -> Option<PathBuf>

pub fn data_dir() -> Option<PathBuf>

pub fn resolved_models_dir(&self) -> PathBuf

pub fn has_models_dir_override(&self) -> bool

pub fn resolved_default_model(&self) -> String

Resolve the effective default model with idiot-proof fallback chain:

1. MOLD_DEFAULT_MODEL env var (if set and non-empty)
2. Config file default_model (if that model has a custom [models] entry)
3. Config file default_model (if that model is a known manifest model that is downloaded)
4. Last-used model from $MOLD_HOME/last-model (if downloaded)
5. If exactly one model is downloaded, use it automatically
6. Fall back to config value (will trigger auto-pull on use)

pub fn resolve_default_model(&self) -> DefaultModelResolution

Like [resolved_default_model] but also returns which fallback step resolved it.

pub fn read_last_model() -> Option<String>

Read the last-used model. When the DB-backed read hook is installed (production path), defers to it entirely; otherwise reads the legacy $MOLD_HOME/last-model sidecar. Callers doing one-shot sidecar migration should use Self::read_last_model_from_sidecar directly.

pub fn read_last_model_from_sidecar() -> Option<String>

Read the legacy $MOLD_HOME/last-model sidecar directly. Used by the one-shot config.toml + sidecar → DB migration.

pub fn resolved_output_dir(&self) -> Option<PathBuf>

Resolve the output directory for server-mode image persistence. MOLD_OUTPUT_DIR env var takes precedence over the config file value. Returns None when disabled (default).

pub fn is_output_disabled(&self) -> bool

Check if image output has been explicitly disabled by the user (empty MOLD_OUTPUT_DIR env var or empty output_dir config field).

pub fn effective_output_dir(&self) -> PathBuf

Resolved output directory with a default fallback to ~/.mold/output/. Unlike resolved_output_dir(), this always returns a path.

pub fn resolved_media_roots(&self) -> Vec<PathBuf>

pub fn resolved_log_dir(&self) -> PathBuf

Resolved log directory from config or default (~/.mold/logs/).

pub fn effective_embed_metadata(&self, override_value: Option<bool>) -> bool

pub fn discovered_manifest_paths(&self, name: &str) -> Option<ModelPaths>

pub fn manifest_model_is_downloaded(&self, name: &str) -> bool

pub fn manifest_model_needs_download(&self, name: &str) -> bool

Return true when a known manifest-backed model is missing any required downloadable asset and should be repaired with mold pull.

pub fn model_config(&self, name: &str) -> ModelConfig

Return the ModelConfig for a given model name, or an empty default. Tries the exact name first, then the canonical name:tag form.

pub fn resolved_model_config(&self, name: &str) -> ModelConfig

Return a model config merged with manifest defaults and metadata.

pub fn upsert_model(&mut self, name: String, config: ModelConfig)

Insert or update a model configuration entry.

pub fn remove_model(&mut self, name: &str) -> Option<ModelConfig>

Remove a model entry from the config, returning it if it existed.

pub fn resolved_placement(&self, model_name: &str) -> Option<DevicePlacement>

Return the effective placement for a model: config entry plus env overrides.

Precedence (higher wins):

1. MOLD_PLACE_TRANSFORMER, MOLD_PLACE_VAE, MOLD_PLACE_TEXT_ENCODERS, MOLD_PLACE_T5, MOLD_PLACE_CLIP_L, MOLD_PLACE_CLIP_G, MOLD_PLACE_QWEN (env overrides per-component).
2. Config file [models."name:tag".placement] table.
3. None (use engine auto).

Each env var parses:

• "auto" — DeviceRef::Auto
• "cpu" — DeviceRef::Cpu
• "gpu:N" — DeviceRef::Gpu { ordinal: N }
• "gpu" — DeviceRef::Gpu { ordinal: 0 }

pub fn set_model_placement( &mut self, model_name: &str, placement: Option<DevicePlacement>, )

Persist a placement for model_name, creating the model entry if missing. None clears the placement (and leaves the rest of the entry intact).

pub fn save(&self) -> Result<()>

Write the config to disk at config_path().

Safety: refuses to save if models_dir points to a temp/test directory, which can happen when tests race on the MOLD_HOME env var.

pub fn save_bootstrap_only_to(&self, path: &Path) -> Result<()>

Serialize only the bootstrap/ops slice of the config to TOML: identifiers, paths, ports, credentials, logging, runpod, per-model file-path entries. User-preference fields that now live in the DB (expand.*, generate.* globals, per-model generation defaults, lora, scheduler) are stripped.

Used by the post-migration rewrite to keep config.toml honest after the user-preference surface has moved to SQLite.

pub fn save_bootstrap_only(&self) -> Result<()>

Save the bootstrap-only slice to the default config path.

pub fn exists_on_disk() -> bool

Whether a config file exists on disk.

pub fn lookup_model_config(&self, name: &str) -> Option<ModelConfig>

Look up a model config entry by name (exact or canonical name:tag form). Public so CLI commands can check whether a model has a custom config entry.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Config

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for Config

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.