What causes "database is a required field in publish config" in clockworklabs/SpacetimeDB?

Open spacetime.json and add `"database": " "` to every [[project.publish]] entry

clockworklabs/SpacetimeDB · error · anyhow::Error

database is a required field in publish config

Error message

database is a required field in publish config

What it means

`spacetime dev` reads the project's publish configs (the `[[project.publish]]` entries in spacetime.json) to know which database(s) to stream logs from. Each entry must contain a string-valued `database` field; this error fires during the pre-flight collection of database names (dev.rs:668) when any publish entry lacks `database` or has it as a non-string JSON value.

Solutions

Open spacetime.json and add `"database": "<your-db-name>"` to every [[project.publish]] entry
Verify the value is a JSON string, not a number or object
Validate the file with `spacetime generate`-style config checks or `cat spacetime.json | jq` before running dev

Example fix

// spacetime.json — before
{
  "project": {
    "publish": [{ "module_path": "server" }]
  }
}
// after
{
  "project": {
    "publish": [{ "module_path": "server", "database": "mydb" }]
  }
}

Defensive patterns

Strategy: validation

Validate before calling

# jq guard before `spacetime dev`:
jq -e 'all(.project.publish[]?; (.database | type) == "string" and .database != "")' \
  spacetime.json >/dev/null || { echo 'every [[project.publish]] needs a string database'; exit 2; }

Prevention

Treat `database` as a required key in every publish entry; add it at authoring time
Validate spacetime.json with jq in a pre-dev/pre-commit hook
When adding a second publish target, remember each entry needs its own database field

When it happens

Trigger: A spacetime.json containing a `[[project.publish]]` object without a `database` key, or with `database = 123` / nested object instead of a string. dev mode collects names via get_config_value("database").and_then(as_str) for EVERY publish entry before starting, so one malformed entry aborts the whole run.

Common situations: Hand-editing spacetime.json and dropping the field; templates or generators that emit publish entries with only module_path; migrating from an older config schema where database was implied; copying a multi-project config where one entry was left half-finished.

Related errors

AI-assisted analysis of clockworklabs/SpacetimeDB@3653d2ed49 (2026-08-20). Data as JSON: /api/errors/6bdedb515e60b27a. Report an issue: GitHub.

Appendix: source

Thrown at crates/cli/src/subcommands/dev.rs:690

        if sc.dev.as_ref().and_then(|d| d.run.as_ref()).is_none() {
            detect_and_save_client_command(&project_dir, Some(sc.clone()))
        } else {
            sc.dev.as_ref().and_then(|d| d.run.clone())
        }
    } else {
        // No config file - try to detect and create new
        detect_and_save_client_command(&project_dir, None)
    };

    // Extract database names from publish configs for log streaming
    let db_names_for_logging: Vec<String> = publish_configs
        .iter()
        .map(|config| {
            config
                .get_config_value("database")
                .and_then(|v| v.as_str())
                .ok_or_else(|| anyhow::anyhow!("database is a required field in publish config"))
                .map(|s| s.to_string())
        })
        .collect::<Result<Vec<_>, _>>()?;

    // Use first database for client process
    let db_name_for_client = &db_names_for_logging[0];

    // Extract watch directories from publish configs
    let watch_dirs = extract_watch_dirs(&publish_configs, &spacetimedb_dir, &project_dir);

    println!("\n{}", "Starting development mode...".green().bold());
    if db_names_for_logging.len() == 1 {
        println!("Database: {}", db_names_for_logging[0].cyan());
    } else {
        println!("Databases: {}", db_names_for_logging.join(", ").cyan());
    }

    // Announce watch directories

View on GitHub (pinned to 3653d2ed49)