wasmerio/wasmer · error · anyhow::Error

invalid value for - expected 0/false|1/true

Error message

invalid value for {} - expected 0/false|1/true: '{other}'

What it means

WasmerClient::new_with_client parses the env var WASMER_LOG_VARIABLES (Self::ENV_VAR_LOG_VARIABLES) as a boolean flag. Only "1", "true", "0", "false", or empty are accepted; any other value causes a bail with this message naming the env var and offending value.

Solutions

1. Set the env var to exactly "1", "true", "0", "false", or unset it entirely.
2. Normalize the value before launching: lowercase it and trim whitespace.
3. If you need richer toggle semantics, propose extending the parser to accept yes/no or case-insensitive true/false.

Example fix

// before
export WASMER_LOG_VARIABLES=yes
// after
export WASMER_LOG_VARIABLES=true

fn valid_bool_env(v: &str) -> bool {
    matches!(v.trim().to_ascii_lowercase().as_str(), "" | "0" | "1" | "true" | "false")
}
// check before launching: valid_bool_env(&env::var("WASMER_LOG_VARIABLES").unwrap_or_default())

When it happens

Trigger: Setting the log-variables environment variable to anything other than 0/1/true/false/empty — e.g. WASMER_LOG_VARIABLES=yes, on, or True (capitalized) — before creating a WasmerClient.

Common situations: Users setting the toggle to "yes"/"on" out of habit, shell capitalization ("True"), or copy-pasting a value with stray whitespace.

Understand the failure class

Background: "is not a valid" / "Invalid ... value" environment variable errors: how libraries validate env vars and what to do when they reject yours — this error's family across 48 libraries.

Related errors

• user agent must not be empty
• Invalid job trigger ' '. Must be 'pre-deployment'…
• invalid node type returned
• invocation start must not be after end
• App deletion failed for an unknown reason

AI-assisted analysis of wasmerio/wasmer@8c4b9ee9d3 (2026-09-01). Data as JSON: /api/errors/94e8faf13e30d065. Report an issue: GitHub.

Appendix: source

Thrown at lib/backend-api/src/client.rs:65

        user_agent
            .parse()
            .with_context(|| format!("invalid user agent: '{user_agent}'"))
    }

    pub fn new_with_client(
        client: reqwest::Client,
        graphql_endpoint: Url,
        user_agent: &str,
    ) -> Result<Self, anyhow::Error> {
        let log_variables = {
            let v = std::env::var(Self::ENV_VAR_LOG_VARIABLES).unwrap_or_default();
            match v.as_str() {
                "1" | "true" => true,
                "0" | "false" => false,
                // Default case if not provided.
                "" => false,
                other => {
                    bail!(
                        "invalid value for {} - expected 0/false|1/true: '{other}'",
                        Self::ENV_VAR_LOG_VARIABLES
                    );
                }
            }
        };

        Ok(Self {
            client,
            auth_token: None,
            user_agent: Self::parse_user_agent(user_agent)?,
            graphql_endpoint,
            log_variables,
        })
    }

    pub fn new(graphql_endpoint: Url, user_agent: &str) -> Result<Self, anyhow::Error> {
        Self::new_with_proxy(graphql_endpoint, user_agent, None)

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