Module limits 

Per-field and per-collection size limits for wire protocol payloads.

Post-deserialization validation prevents O(N) or O(N*M) processing attacks within the 1 MB WebSocket frame limit. All limits are set above real-world maximums with generous headroom to avoid breaking legitimate payloads.

Design decision: post-deserialization validation

We use a WireValidate trait (not custom serde deserializers) because:

• Custom deserializers are verbose and fragile for dozens of fields
• The 1 MB frame limit already caps total memory; the concern is processing cost
• Consistent with the existing Validate pattern in web-api-types
• Trivially backward-compatible (limits set far above real-world maximums)

Structs

WireValidationError

Error returned when a wire payload field exceeds its size limit.

Constants

MAX_ACTIVE_MQTT_CLIENTS

Maximum number of active MQTT client IDs.

MAX_BATCH_UPDATES

Maximum number of packages in a batch update.

MAX_BATCH_UPDATE_RESULTS

Maximum number of results in a batch update result.

MAX_CAPABILITIES

Maximum number of capabilities in a capability set.

MAX_CAPABILITIES_PER_SERVICE

Maximum number of capabilities in a single Register message.

MAX_CONFIG_TEST_OUTPUT_LEN

Maximum byte length of a config test output string.

MAX_CONNECTIVITY_UPDATES

Maximum number of connectivity updates in a HostConnectivityUpdated message.

MAX_DISCOVERED_QUALIFIER_LEN

Maximum byte length of a DiscoveredSoftware.qualifier string.

MAX_DISCOVERIES_PER_PLUGIN

Maximum number of discoveries per plugin result.

MAX_DISCOVERY_PLUGINS

Maximum number of discovery plugins in a single message.

MAX_DISCOVERY_PLUGIN_RESULTS

Maximum number of discovery plugin results in a single message.

MAX_HOST_PACKAGE_HOST_STATES

Maximum number of host package host states.

MAX_HOST_TAGS

Maximum number of tags per host in a HostStateMetadata entry.

MAX_ICON_URL_LEN

Maximum byte length of a software item icon URL.

MAX_LONG_STRING_LEN

Maximum length for long strings (PEM certificates, CSRs, release notes).

MAX_MEDIUM_STRING_LEN

Maximum length for medium strings (hostnames, error messages).

MAX_MQTT_HOSTS

Maximum number of host metadata entries in a SoftwareStates message.

MAX_MQTT_TENANTS

Maximum number of MQTT tenants in an assignment message.

MAX_OUTPUT_STRING_LEN

Maximum length for output strings (command output, update output). Matches the 1 MB frame limit — output is already bounded by MAX_OUTPUT_BYTES in agent-core/src/update.rs.

MAX_PENDING_REPORTS_PER_CONNECTION

Maximum number of concurrent pending (incomplete) paginated reports per WebSocket connection. Prevents memory exhaustion from abandoned reports.

MAX_PLUGIN_CONFIG_JSON_LEN

Maximum byte length of plugin config JSON in a ReportPluginConfig message.

MAX_RELEASE_ASSETS

Maximum number of assets in a ReleaseInfo message.

MAX_REPORT_HOSTS

Maximum number of hosts in a ReportHosts message.

MAX_REPORT_PAGES

Maximum number of pages in a single paginated report.

MAX_SERVICE_CONFIG_ENTRIES

Maximum number of entries in a ServiceConfigDelivery or ServiceConfigUpdated message.

MAX_SERVICE_CONFIG_VALUE_LEN

Maximum byte length of a service config value (serialized JSON).

MAX_SHORT_STRING_LEN

Maximum length for short strings (identifiers, names, versions).

MAX_SOFTWARE_STATE_HOSTS

Maximum number of hosts per software state item.

MAX_SOFTWARE_STATE_ITEMS

Maximum number of software state items.

MAX_SPAN_ID_LEN

Maximum length of a span ID (16 hex chars for 64-bit W3C span ID).

MAX_STDIN_DATA_LEN

Maximum byte length of stdin data in an UpdateStdinData message (64 KB).

MAX_SURFACE_ACTIONS

Maximum number of interaction descriptors in a surface registration.

MAX_SURFACE_ACTION_REFS

Maximum number of action ID references in a single surface node.

MAX_SURFACE_COLUMNS

Maximum number of columns in a TableColumns placement or DataTable UI.

MAX_SURFACE_FIELDS

Maximum number of fields in a single form.

MAX_SURFACE_JSON_DEPTH

Maximum nesting depth for JSON values carried in surface payloads.

MAX_SURFACE_JSON_NODES

Maximum number of nodes visited when traversing surface JSON values.

MAX_SURFACE_MANIFESTS

Maximum number of surfaces in a single SurfaceRegistration message.

MAX_SURFACE_PARAMS_LEN

Maximum byte length of surface action params JSON.

MAX_SURFACE_RESPONSE_LEN

Maximum byte length of surface action response JSON.

MAX_SURFACE_SELECT_OPTIONS

Maximum number of options in a select field.

MAX_SURFACE_WIZARD_STEPS

Maximum number of steps in a wizard.

MAX_TRACE_ID_LEN

Maximum length of a trace ID (32 hex chars for 128-bit W3C trace ID).

MAX_UPDATE_HOOKS

Maximum number of pre/post-update hook plugins in an update message.

MAX_VERSION_CHECK_ASSIGNMENTS

Maximum number of version check assignments in a single message.

MAX_VERSION_CHECK_RESULTS

Maximum number of version check results in a single message.

MAX_WORKLOAD_CLAIM_KEYS

Maximum number of config keys in a single WorkloadClaim message.

PAGINATION_SIZE_THRESHOLD

Serialized JSON size threshold (768 KB) above which a payload is split into pages. Well under the 1 MB WebSocket frame limit to leave headroom for the envelope overhead (protocol_version, seq, trace_context, pagination, type tag).

REPORT_IDLE_TIMEOUT

Idle timeout after the last page of a paginated report (15 s).

REPORT_TOTAL_TIMEOUT

Total timeout for a paginated report from first page to completion (5 min).

SHA256_DIGEST_LEN

Expected byte length of a SHA-256 hex digest string (64 hex characters).

STATES_HOST_PAGE_SIZE

Number of active hosts processed per page in paginated MQTT software-states delivery.

Traits

WireValidate

Trait for post-deserialization validation of wire protocol payloads.

Functions

check_map_len

Check that a BTreeMap does not exceed the given length limit.

check_opt_string_len

Check that an Option<String> does not exceed the given byte length limit.

check_set_len

Check that a BTreeSet does not exceed the given length limit.

check_string_len

Check that a String does not exceed the given byte length limit.

check_vec_len

Check that a Vec does not exceed the given length limit.