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# Contract: Directory Data Provider
The only component permitted to talk to Microsoft Graph. Implements OTD-002, OTD-004, and OTD-007.
Everything below the normalization boundary is invisible to the rule engine (Principle IV).
**Transport**: `Invoke-MgGraphRequest` from `Microsoft.Graph.Authentication` (OTD-004). No
resource-specific SDK modules.
## Authentication (FR-003)
| Function | Environment | Mechanism |
| --- | --- | --- |
| `Connect-PersonaGraphManagedIdentity` | Azure Automation | `Connect-MgGraph -Identity` |
| `Connect-PersonaGraphInteractive` | Local development | `Connect-MgGraph -Scopes <read scopes>` |
Both return an opaque connection handle. No token, header, or secret is ever returned to a caller,
logged, or written to an audit record.
## Permissions (OTD-002)
| Function | Application permission |
| --- | --- |
| `Get-PersonaUsers` | `User.Read.All` (or `User.ReadWrite.All` for the enforcement identity) |
| `Get-PersonaGroupMembership` | `GroupMember.Read.All` |
| `Get-PersonaDirectoryRoles` | `RoleManagement.Read.Directory` |
| `Set-UserPersonaAttribute` | `User.ReadWrite.All` |
`Directory.Read.All` is prohibited — materially broader than the three read permissions combined.
## Read operations
### `Get-PersonaUsers`
```text
GET /v1.0/users?$select=<fields>&$top=999
```
- `$select` carries the FR-005 baseline (`id`, `userPrincipalName`, `displayName`, `userType`,
`accountEnabled`, `companyName`, `jobTitle`, `department`) plus the configured target attribute and
any property referenced by an enabled rule. Unused properties are not requested.
- The persona directory extension is selected by its full name,
`extension_<EXTENSION-APP-ID>_<APPROVED-PERSONA-ATTRIBUTE-NAME>`.
- Pagination follows `@odata.nextLink` until absent (FR-004). A truncated enumeration MUST raise —
never return a partial population as if complete.
- `-UserObjectId` switches to `GET /v1.0/users/{id}?$select=...`.
### `Get-PersonaGroupMembership`
```text
GET /v1.0/users/{id}/memberOf # direct
GET /v1.0/users/{id}/transitiveMemberOf # transitive
```
Mode comes from the condition, falling back to `engine.defaultMembershipMode` (RE-007).
**Return contract**: always a `MembershipRecord`. On failure it returns a record with
`RetrievalSucceeded = $false` and a `FailureReason` — it MUST NOT return an empty list, and MUST NOT
throw past the per-user boundary. This single behaviour is what makes FR-013 work: unknown membership
becomes `EvaluationError`, never a false non-match.
### `Get-PersonaDirectoryRoles`
```text
GET /v1.0/roleManagement/directory/roleAssignments?$filter=principalId eq '<id>'
```
Eligible (PIM) assignments are out of scope for v1 unless authorization is confirmed.
### Caching
Group and role data reusable across users is cached for the run's lifetime (NFR-002). The cache is
keyed by group or role Object ID and is **never** persisted between runs — a stale cache would make
results depend on run history, breaking Principle I.
## Write operation
### `New-PersonaWriteBody`
The **only** function permitted to construct a write body (OTD-003 control 3).
```powershell
# Returns exactly one key.
@{ "<engine.targetAttribute>" = "<CalculatedPersona>" }
```
Contract:
- Throws if the attribute name is not `engine.targetAttribute`.
- Throws if the attribute is absent from `approvedWritableAttributes`.
- Returns a hashtable whose `Count` is exactly `1`. Tests assert on this directly (SC-005).
### `Set-UserPersonaAttribute`
```text
PATCH /v1.0/users/{id}
Content-Type: application/json
<body from New-PersonaWriteBody>
```
- Callable **only** when `ShouldProcess` returned `$true`. Under `-WhatIf` this function is not
reached — the caller does not construct a request at all (SC-004). Preview mode is an absence of a
call, not a suppressed call.
- A failure returns `UpdateFailed` for that user and does not terminate the run.
## Retry policy (OTD-007)
| Aspect | Value |
| --- | --- |
| Retryable | 429, 500, 502, 503, 504, transport timeout |
| Never retried | 400, 401, 403, 404, 409 |
| `Retry-After` | Honoured when present; overrides computed backoff |
| Attempts | Max 5 |
| Backoff | Exponential from 1s, full jitter, per-delay cap 60s |
| Logging | Attempt number, status code, and delay on every retry |
Exhausted retries on **required** data produce `EvaluationError` for the affected user (FR-013).
Exhausted retries during enumeration are fatal (exit code `3`).
## Prohibited in this layer
- Logging tokens, `Authorization` headers, or full response bodies (Principle V).
- Returning raw Graph objects past `ConvertTo-Persona*Record`.
- Any reference to rule, persona, or condition concepts — this layer moves data, it does not decide.