tandem-server 0.6.9

HTTP server for Tandem engine APIs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
use std::{sync::Arc, time::Duration};

use tandem_core::{
    evaluate_dispatch_boundary, DataBoundaryDispatchContext, DataBoundaryDispatchOutcome,
    PermissionManager,
};
use tandem_data_boundary::{
    DataBoundaryTenantRef, ProviderEgressAuditEvent, ProviderEgressAuthority, ProviderEgressPermit,
    SensitiveDataClass,
};
use tandem_memory::{MemoryProviderEgressApprovalHandler, MemoryProviderEgressContext};
use tandem_providers::ChatMessage;
use tandem_types::{EngineEvent, TenantContext, VerifiedTenantContext};
use tokio_util::sync::CancellationToken;

use crate::AppState;

const PROVIDER_EGRESS_APPROVAL_TIMEOUT: Duration = Duration::from_secs(30);

async fn persist_and_publish_dispatch_event(
    state: &AppState,
    mut event: EngineEvent,
) -> Result<(), String> {
    let recorded = crate::data_boundary_bridge::record_data_boundary_protected_audit(state, &event)
        .await
        .map_err(|error| {
            format!(
                "DATA_BOUNDARY_AUDIT_FAILED: provider dispatch denied because protected audit persistence failed: {error:#}"
            )
        })?;
    if recorded {
        crate::data_boundary_bridge::mark_data_boundary_protected_audit_recorded(&mut event);
    }
    state.event_bus.publish(event);
    Ok(())
}

async fn wait_for_provider_egress_reply(
    permissions: &PermissionManager,
    request_id: &str,
) -> (Option<String>, bool) {
    permissions
        .wait_for_reply_with_timeout(
            request_id,
            CancellationToken::new(),
            Some(PROVIDER_EGRESS_APPROVAL_TIMEOUT),
        )
        .await
}

pub(crate) fn authority_for_dispatch(
    tenant_context: Option<&TenantContext>,
    verified_tenant_context: Option<&VerifiedTenantContext>,
    run_id: Option<&str>,
    session_id: Option<&str>,
) -> ProviderEgressAuthority {
    let tenant = tenant_context
        .filter(|tenant| !tenant.is_local_implicit())
        .map(|tenant| DataBoundaryTenantRef {
            organization_id: Some(tenant.org_id.clone()),
            workspace_id: Some(tenant.workspace_id.clone()),
            deployment_id: tenant.deployment_id.clone(),
        })
        .unwrap_or_default();
    ProviderEgressAuthority {
        tenant,
        run_id: run_id.map(str::to_string),
        session_id: session_id.map(str::to_string),
        authority_ref: verified_tenant_context.map(|verified| verified.assertion_id.clone()),
    }
}

pub(crate) fn memory_egress_context(
    state: &AppState,
    tenant_context: Option<&TenantContext>,
    verified_tenant_context: Option<&VerifiedTenantContext>,
    run_id: Option<&str>,
    session_id: Option<&str>,
) -> MemoryProviderEgressContext {
    let authority =
        authority_for_dispatch(tenant_context, verified_tenant_context, run_id, session_id);
    let audit_state = state.clone();
    let context = MemoryProviderEgressContext::new(authority).with_audit_sink(Arc::new(
        move |event: ProviderEgressAuditEvent| {
            let state = audit_state.clone();
            Box::pin(async move {
                let event_name = event.boundary.event_name.clone();
                let properties = serde_json::to_value(event).map_err(|error| {
                    format!("DATA_BOUNDARY_AUDIT_FAILED: serialize memory decision: {error}")
                })?;
                persist_and_publish_dispatch_event(&state, EngineEvent::new(event_name, properties))
                    .await
            })
        },
    ));
    let permissions = state
        .runtime
        .get()
        .map(|runtime| runtime.permissions.clone());
    let approval_session_id = session_id.map(str::to_string);
    let approval_handler: MemoryProviderEgressApprovalHandler = Arc::new(move |event| {
        let permissions = permissions.clone();
        let session_id = approval_session_id.clone();
        Box::pin(async move {
            let permissions = permissions.ok_or_else(|| {
                "DATA_BOUNDARY_APPROVAL_UNAVAILABLE: memory runtime is not initialized".to_string()
            })?;
            let pending = permissions
                .ask_for_session(
                    session_id.as_deref(),
                    "data_boundary_egress",
                    serde_json::json!({
                        "kind": "memory_provider_egress",
                        "decisionID": event.boundary.decision_id,
                        "payloadHash": event.boundary.payload_hash,
                        "findingSummary": event.boundary.finding_summary,
                        "semanticDataClasses": event.semantic_data_classes,
                        "reasonCodes": event.boundary.reason_codes,
                    }),
                )
                .await;
            let (reply, timed_out) =
                wait_for_provider_egress_reply(&permissions, &pending.id).await;
            if matches!(
                reply.as_deref(),
                Some("once") | Some("always") | Some("allow")
            ) {
                Ok(pending.id)
            } else {
                Err(format!(
                    "DATA_BOUNDARY_APPROVAL_REQUIRED: memory provider dispatch approval {}",
                    if timed_out { "timed out" } else { "was denied" }
                ))
            }
        })
    });
    context.with_approval_handler(approval_handler)
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum ServerProviderEgressKind {
    MissionBuilder,
    WorkflowPlanner,
    KnowledgeBase,
}

impl ServerProviderEgressKind {
    fn data_classes(self) -> &'static [SensitiveDataClass] {
        match self {
            Self::MissionBuilder | Self::WorkflowPlanner => &[
                SensitiveDataClass::CustomerData,
                SensitiveDataClass::SourceCode,
                SensitiveDataClass::ProprietaryBusinessData,
            ],
            Self::KnowledgeBase => &[
                SensitiveDataClass::CustomerData,
                SensitiveDataClass::Legal,
                SensitiveDataClass::ProprietaryBusinessData,
            ],
        }
    }
}

pub(crate) struct PreparedChatDispatch {
    pub(crate) messages: Vec<ChatMessage>,
    pub(crate) permit: ProviderEgressPermit,
}

#[allow(clippy::too_many_arguments)]
pub(crate) async fn prepare_chat_messages(
    state: &AppState,
    tenant_context: Option<&TenantContext>,
    verified_tenant_context: Option<&VerifiedTenantContext>,
    run_id: Option<&str>,
    session_id: &str,
    operation_id: &str,
    source_ref: &str,
    kind: ServerProviderEgressKind,
    provider_id: &str,
    model_id: Option<&str>,
    messages: &[ChatMessage],
) -> Result<PreparedChatDispatch, String> {
    let authority = authority_for_dispatch(
        tenant_context,
        verified_tenant_context,
        run_id,
        Some(session_id),
    );
    match evaluate_dispatch_boundary(
        &DataBoundaryDispatchContext {
            session_id,
            run_id,
            message_id: operation_id,
            correlation_id: None,
            provider_id,
            model_id,
            tool_schema_payload: None,
            source_ref,
            data_classes: kind.data_classes(),
            authority_ref: authority.authority_ref.as_deref(),
            org_id: authority.tenant.organization_id.as_deref(),
            workspace_id: authority.tenant.workspace_id.as_deref(),
            deployment_id: authority.tenant.deployment_id.as_deref(),
        },
        messages,
    ) {
        DataBoundaryDispatchOutcome::Off { permit } => Ok(PreparedChatDispatch {
            messages: messages.to_vec(),
            permit,
        }),
        DataBoundaryDispatchOutcome::Proceed { event, permit } => {
            persist_and_publish_dispatch_event(state, event).await?;
            Ok(PreparedChatDispatch {
                messages: messages.to_vec(),
                permit,
            })
        }
        DataBoundaryDispatchOutcome::ProceedTransformed {
            event,
            messages,
            permit,
        } => {
            persist_and_publish_dispatch_event(state, event).await?;
            Ok(PreparedChatDispatch { messages, permit })
        }
        DataBoundaryDispatchOutcome::RequireApproval {
            event,
            evidence,
            denial_reason,
            approval,
        } => {
            persist_and_publish_dispatch_event(state, event).await?;
            let permissions = state
                .runtime
                .get()
                .map(|runtime| runtime.permissions.clone())
                .ok_or_else(|| {
                    format!(
                        "{denial_reason} (direct provider runtime has no approval continuation)"
                    )
                })?;
            let pending = permissions
                .ask_for_session(Some(session_id), "data_boundary_egress", evidence)
                .await;
            let (reply, timed_out) =
                wait_for_provider_egress_reply(&permissions, &pending.id).await;
            if !matches!(
                reply.as_deref(),
                Some("once") | Some("always") | Some("allow")
            ) {
                return Err(format!(
                    "{denial_reason} ({})",
                    if timed_out {
                        "approval timed out"
                    } else {
                        "approval denied"
                    }
                ));
            }
            Ok(PreparedChatDispatch {
                messages: messages.to_vec(),
                permit: approval.approve(pending.id)?,
            })
        }
        DataBoundaryDispatchOutcome::Blocked { event, reason } => {
            persist_and_publish_dispatch_event(state, event).await?;
            Err(reason)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::ffi::OsString;

    const APPROVAL_RESPONDER_TIMEOUT: Duration = Duration::from_secs(5);

    struct EnvRestore(Vec<(&'static str, Option<OsString>)>);

    impl EnvRestore {
        fn set(values: &[(&'static str, &str)]) -> Self {
            let restore = Self(
                values
                    .iter()
                    .map(|(name, _)| (*name, std::env::var_os(name)))
                    .collect(),
            );
            for (name, value) in values {
                std::env::set_var(name, value);
            }
            restore
        }
    }

    impl Drop for EnvRestore {
        fn drop(&mut self) {
            for (name, value) in self.0.drain(..) {
                match value {
                    Some(value) => std::env::set_var(name, value),
                    None => std::env::remove_var(name),
                }
            }
        }
    }

    #[test]
    fn direct_provider_surfaces_have_trusted_semantic_classes() {
        for kind in [
            ServerProviderEgressKind::MissionBuilder,
            ServerProviderEgressKind::WorkflowPlanner,
        ] {
            assert!(kind
                .data_classes()
                .contains(&SensitiveDataClass::SourceCode));
            assert!(kind
                .data_classes()
                .contains(&SensitiveDataClass::CustomerData));
            assert!(kind
                .data_classes()
                .contains(&SensitiveDataClass::ProprietaryBusinessData));
        }
        let kb = ServerProviderEgressKind::KnowledgeBase.data_classes();
        assert!(kb.contains(&SensitiveDataClass::Legal));
        assert!(kb.contains(&SensitiveDataClass::CustomerData));
        assert!(kb.contains(&SensitiveDataClass::ProprietaryBusinessData));
    }

    #[tokio::test]
    #[serial_test::serial(data_boundary_env)]
    async fn direct_provider_approval_continuation_activates_route_bound_permit() {
        let _env = EnvRestore::set(&[
            ("TANDEM_DATA_BOUNDARY_MODE", "enforce"),
            ("TANDEM_DATA_BOUNDARY_STRICT", "1"),
            (
                "TANDEM_DATA_BOUNDARY_PROVIDER_CLASSES",
                "test-provider=approved_external",
            ),
            ("TANDEM_DATA_BOUNDARY_APPROVAL_CLASSES", "customer_data"),
        ]);

        let state = crate::test_support::test_state().await;
        let mut published_events = state.event_bus.subscribe();
        let mut events = state.event_bus.subscribe();
        let permissions = state.runtime.wait().permissions.clone();
        let reply_task = tokio::spawn(async move {
            tokio::time::timeout(APPROVAL_RESPONDER_TIMEOUT, async move {
                loop {
                    let event = events.recv().await.expect("permission event");
                    if event.event_type != "permission.asked" {
                        continue;
                    }
                    let request_id = event.properties["requestID"]
                        .as_str()
                        .expect("permission request id");
                    assert!(permissions.reply(request_id, "allow").await);
                    break;
                }
            })
            .await
            .expect("approval responder timed out");
        });
        let tenant = TenantContext::explicit_user_workspace("org-a", "workspace-a", None, "user-a");
        let messages = [ChatMessage {
            role: "user".to_string(),
            content: "ordinary mission content".to_string(),
            attachments: Vec::new(),
        }];
        let prepared = tokio::time::timeout(
            APPROVAL_RESPONDER_TIMEOUT,
            prepare_chat_messages(
                &state,
                Some(&tenant),
                None,
                Some("run-a"),
                "session-a",
                "operation-a",
                "server.mission_builder",
                ServerProviderEgressKind::MissionBuilder,
                "test-provider",
                Some("test-model"),
                &messages,
            ),
        )
        .await
        .expect("approval preparation timed out")
        .expect("approved direct dispatch");
        reply_task.await.expect("approval reply task");
        assert_eq!(prepared.messages.len(), 1);
        assert_eq!(prepared.messages[0].role, messages[0].role);
        assert_eq!(prepared.messages[0].content, messages[0].content);
        assert!(prepared.permit.approval_ref().is_some());
        let fields = [
            tandem_data_boundary::ProviderEgressField::untransformable(
                "message.0.role",
                prepared.messages[0].role.as_str(),
            ),
            tandem_data_boundary::ProviderEgressField::transformable(
                "message.0.content",
                prepared.messages[0].content.as_str(),
            ),
        ];
        assert!(prepared
            .permit
            .ensure_request(
                Some("test-provider"),
                Some("test-model"),
                &tandem_data_boundary::provider_egress_payload_hash(&fields),
            )
            .is_ok());

        let boundary_event = tokio::time::timeout(APPROVAL_RESPONDER_TIMEOUT, async {
            loop {
                let event = published_events.recv().await.expect("published event");
                if event.event_type.starts_with("data_boundary.") {
                    break event;
                }
            }
        })
        .await
        .expect("boundary event timed out");
        let ledger_before_bridge = tokio::fs::read_to_string(&state.protected_audit_path)
            .await
            .expect("protected audit ledger");
        assert_eq!(ledger_before_bridge.lines().count(), 1);
        assert!(
            !crate::data_boundary_bridge::record_data_boundary_protected_audit(
                &state,
                &boundary_event,
            )
            .await
            .expect("bridge replay"),
            "the bridge must skip synchronously persisted provider evidence"
        );
        let ledger_after_bridge = tokio::fs::read_to_string(&state.protected_audit_path)
            .await
            .expect("protected audit ledger after bridge replay");
        assert_eq!(ledger_after_bridge.lines().count(), 1);
    }

    #[tokio::test]
    #[serial_test::serial(data_boundary_env)]
    async fn protected_audit_failure_blocks_direct_provider_permit() {
        let _env = EnvRestore::set(&[
            ("TANDEM_DATA_BOUNDARY_MODE", "audit"),
            (
                "TANDEM_DATA_BOUNDARY_PROVIDER_CLASSES",
                "test-provider=prohibited",
            ),
        ]);

        let mut state = crate::test_support::test_state().await;
        let failed_ledger_path = state
            .protected_audit_path
            .with_file_name("protected-audit-path-is-a-directory");
        tokio::fs::create_dir_all(&failed_ledger_path)
            .await
            .expect("create invalid ledger path");
        state.protected_audit_path = failed_ledger_path;
        let mut events = state.event_bus.subscribe();
        let tenant = TenantContext::explicit_user_workspace("org-a", "workspace-a", None, "user-a");
        let messages = [ChatMessage {
            role: "user".to_string(),
            content: "ordinary mission content".to_string(),
            attachments: Vec::new(),
        }];

        let result = prepare_chat_messages(
            &state,
            Some(&tenant),
            None,
            Some("run-audit-failure"),
            "session-audit-failure",
            "operation-audit-failure",
            "server.mission_builder",
            ServerProviderEgressKind::MissionBuilder,
            "test-provider",
            Some("test-model"),
            &messages,
        )
        .await;
        let error = match result {
            Ok(_) => panic!("audit failure must prevent a dispatch permit"),
            Err(error) => error,
        };

        assert!(error.contains("DATA_BOUNDARY_AUDIT_FAILED"), "{error}");
        assert!(
            events.try_recv().is_err(),
            "failed audit must not publish an authorization-like boundary event"
        );
    }
}