feat(python): workflow context propagation quickstart by nelson-parente · Pull Request #1309 · dapr/quickstarts

nelson-parente · 2026-05-19T20:48:07Z

Summary

Python sibling of @cicoyle's canonical Go quickstart for workflow history propagation (Dapr 1.18). Same patient intake / e-prescribing scenario, same 3-level hierarchy, same workflow/activity names — so the Python and Go examples can be compared 1:1.

Ported from: dapr/quickstarts#1315 (tutorials/workflow/go/history-propagation)
Runtime: Dapr 1.18+ (dapr/dapr#9810)
SDK: dapr-ext-workflow==1.18.0rc0 (dapr/python-sdk#1025)
Targets release-1.18 to land alongside the Go example.

Scenario

Patient intake / e-prescribing pipeline. A compliance audit and a pharmacy dispense step refuse to act unless the propagated history proves the required upstream checks (insurance, allergies, drug interactions) actually ran.

PatientIntake (root)
  └─ VerifyInsurance       (activity, no propagation)
  └─ PrescribeMedication   (child wf, PropagationScope.LINEAGE)
        └─ CheckAllergies         (activity, no propagation)
        └─ ScreenDrugInteractions (activity, no propagation)
        └─ ComplianceAudit        (grandchild wf, PropagationScope.LINEAGE)
        |      reads PatientIntake + PrescribeMedication events
        └─ DispenseMedication     (activity, PropagationScope.OWN_HISTORY)
               reads PrescribeMedication events only
               refuses to dispense if the screening lineage is missing

ComplianceAudit uses LINEAGE to verify the full ancestor chain. DispenseMedication uses OWN_HISTORY as a trust boundary — the pharmacy step doesn't get to see the upstream patient-intake chain.

Two scenarios (matches the Go demo)

The app schedules both back-to-back and exits on its own — no Ctrl+C needed:

Lineage forwarded → PrescribeMedication calls DispenseMedication with PropagationScope.OWN_HISTORY; pharmacy verifies and dispenses.
Lineage withheld → PrescribeMedication calls DispenseMedication without propagation; pharmacy receives no history and refuses with a refused DispenseResult.

Python API used (from dapr/python-sdk#1025)

PropagationScope.LINEAGE / PropagationScope.OWN_HISTORY
propagation= kwarg on ctx.call_child_workflow() and ctx.call_activity()
ctx.get_propagated_history() → PropagatedHistory | None
PropagatedHistory.get_last_workflow_by_name(name) → WorkflowResult
WorkflowResult.get_last_activity_by_name(name) → ActivityResult (with .completed, .output)
PropagationNotFoundError

Replay safety

All print() calls inside workflows are guarded by if not ctx.is_replaying: so they only fire on the live execution, not on each durable replay.

Files

tutorials/workflow/python/history-propagation/
├── README.md          # mirrors the Go README, adapted for Python
├── dapr.yaml          # dapr run -f . config (appID=patient-app)
├── makefile           # wires the example into `make validate`
├── app.py             # registry + worker setup, schedules both scenarios
├── models.py          # PatientRecord, ComplianceResult, DispenseResult
├── workflow.py        # workflow + activity definitions, history helpers
└── requirements.txt   # Python deps (dapr-ext-workflow==1.18.0rc0)

Test plan

pip3 install -r requirements.txt against dapr-ext-workflow==1.18.0rc0
dapr run -f . against a Dapr 1.18 RC sidecar
Scenario 1: ComplianceAudit reads full ancestor history via LINEAGE (sees PatientIntake + PrescribeMedication); DispenseMedication sees only PrescribeMedication events via OWN_HISTORY and dispenses
Scenario 2: DispenseMedication receives no propagated history and returns refused, PrescribeMedication reports pharmacy refused to dispense
Older sidecar (pre-1.18) gracefully returns None from get_propagated_history() without crash

References

Go sibling (merged): dapr/quickstarts#1315 — tutorials/workflow/go/history-propagation
Proposal: dapr/proposals#102
Runtime: dapr/dapr#9810
Python SDK: dapr/python-sdk#1025
Go SDK reference: dapr/go-sdk#823
.NET sibling: dapr/quickstarts#1310
1.18 endgame: dapr/dapr#9856

Ports Cassie Coyle's Go-SDK reference example (dapr/go-sdk#823) to Python. Demonstrates PropagationScope.LINEAGE and PropagationScope.OWN_HISTORY in a fraud-detection payment scenario with a 3-level workflow hierarchy. Requires Dapr 1.18+ (dapr/dapr#9810) and dapr-ext-workflow 1.18+ (dapr/python-sdk#1025). Signed-off-by: Nelson Parente <nelson_parente@live.com.pt>

Aligns the Python workflow history propagation quickstart with the canonical Go reference (dapr/go-sdk#823, dapr#1315) so all SDK quickstarts share the same patient intake / e-prescribing scenario. - Swap credit-card/fraud scenario for patient-intake/e-prescribing - Adopt PatientIntake -> PrescribeMedication -> ComplianceAudit hierarchy - Add is_replaying guards around all print() calls inside workflows - Use Cassie's PascalCase activity/workflow names for cross-SDK consistency Signed-off-by: Nelson Parente <nelson_parente@live.com.pt>

Aligns the Python workflow history propagation quickstart with Cassie's canonical Go version that merged into release-1.18 (dapr#1315, tutorials/workflow/go/history-propagation). Changes to match the canonical structure: - Move from workflows/python/sdk-context-propagation/order-processor/ to tutorials/workflow/python/history-propagation/, matching the Go sibling at tutorials/workflow/go/history-propagation/ - Split the monolithic app.py into app.py / workflow.py / models.py, mirroring main.go / workflow.go / models.go - Add ForwardLineage flag to PatientRecord and run both scenarios back-to-back (happy path + negative), purging state after each so the app exits on its own - Make DispenseMedication refuse to dispense when no propagated history is received, returning a refused DispenseResult with a Reason field - Match the Go README: title, propagation-scope table, STEP markers, expected output for both scenarios - dapr.yaml: appID=patient-app (was order-processor), resourcesPath=../../resources (was ../../components), appLogDestination/daprdLogDestination=console to match sister Python tutorials and Cassie's Go example - Use correct Python SDK API names: get_last_workflow_by_name / get_last_activity_by_name (the earlier draft used get_workflow_by_name / get_activity_by_name, which were renamed in dapr/python-sdk#1025) Signed-off-by: Nelson Parente <nelson_parente@live.com.pt>

nelson-parente · 2026-05-28T21:27:45Z

Updated to align with @cicoyle's now-merged Go quickstart at tutorials/workflow/go/history-propagation (#1315). Summary of what changed since the last revision:

Location & target branch

Moved files from workflows/python/sdk-context-propagation/order-processor/ → tutorials/workflow/python/history-propagation/, matching the Go sibling.
Retargeted PR base from master → release-1.18 (where Cassie's PR landed).

File layout

Split the previous single app.py into three files mirroring main.go / workflow.go / models.go:
- app.py — registry + worker setup, schedules both scenarios.
- workflow.py — workflow and activity definitions, history helpers.
- models.py — PatientRecord, ComplianceResult, DispenseResult dataclasses.

Behavioural alignment with the Go canonical version

Added forward_lineage: bool field to PatientRecord to control whether PrescribeMedication propagates its history to DispenseMedication.
The app now runs two scenarios back-to-back (was: a single happy path):
1. forward_lineage=True → pharmacy verifies the propagated history and dispenses.
2. forward_lineage=False → pharmacy receives no propagated history and refuses with a refused DispenseResult (added reason field).
After each scenario, the workflow state is purged so the demo exits on its own.

dapr.yaml

appID: order-processor → appID: patient-app (matches the Go example's patient-app).
resourcesPath: ../../components → resourcesPath: ../../resources (matches the convention used by sibling Python tutorials under tutorials/workflow/python/).
Added appLogDestination: console and daprdLogDestination: console.

Python SDK API

Switched to the correct method names from dapr-ext-workflow 1.18: get_last_workflow_by_name / get_last_activity_by_name (the previous draft used get_workflow_by_name / get_activity_by_name, which were renamed in Add history propagation python-sdk#1025).

README

Rewrote to mirror the Go README's structure: title, propagation-scope table, key-demonstration block, both scenarios documented,  markers for make validate, expected-output snippets for both scenarios, file map at the bottom.

No SDK changes were required — the dependency stays at dapr-ext-workflow==1.18.0rc0 from #1307.

alicejgibbons

minor things

alicejgibbons · 2026-05-29T09:52:38Z

 proof — in the propagated history — that the required upstream checks
 (insurance, allergies, drug interactions) actually ran.

+This is the Python sibling of the canonical Go quickstart in


remove this

alicejgibbons · 2026-05-29T09:52:46Z

+[`tutorials/workflow/go/history-propagation`](../../go/history-propagation),
+itself based on [dapr/go-sdk#823](https://github.com/dapr/go-sdk/pull/823).
+Python runtime support landed in
+[dapr/python-sdk#1025](https://github.com/dapr/python-sdk/pull/1025).


alicejgibbons · 2026-05-29T09:54:37Z


-Requires Dapr `1.18.0+` (workflow history propagation), `go-sdk v1.15.0+`,
-and `durabletask-go v0.12.0+`.
+Requires Dapr `1.18.0+` (workflow history propagation),


make this simplier just say 1.18+, no need to specify the sdk

alicejgibbons · 2026-05-29T09:54:54Z

alicejgibbons · 2026-05-29T09:55:42Z

-
+of scope for this quickstart.

 ## Files


REmove this

alicejgibbons · 2026-05-29T09:56:38Z

+        )
+
+    # Step 4: Dispense the medication.
+    # Happy path: attach PropagationScope.OWN_HISTORY — the pharmacy sees our


In general can you make most of these comments simplier? There is a lot of repetition

…code - README: drop the Go-sibling reference paragraph - README: simplify the requirements line to just "Requires Dapr 1.18+" - README: drop the "exits on its own — no Ctrl+C needed" sentence - README: drop the "## Files" tree at the bottom - workflow.py: trim repetitive docstrings and inline Step comments; the step prints already carry the same information Signed-off-by: Nelson Parente <nelson_parente@live.com.pt>

nelson-parente · 2026-05-29T12:38:34Z

Thanks @alicejgibbons — addressed all six in 015fb51:

README

Dropped the Go-sibling paragraph (L14–18).
Simplified the requirements line to Requires Dapr 1.18+. (L114).
Dropped The app runs both scenarios once and exits on its own — no Ctrl+C needed. (L158).
Dropped the ## Files tree at the bottom (L187).

workflow.py

Trimmed the repetitive function docstrings and removed the per-step inline comments — the Step N: ... print statements already carry the same info. Kept one short comment on Step 4 since that's the part the reader actually needs to understand (the two propagation modes side-by-side).

- Merge 'Key demonstration' into 'Scenarios' so the LINEAGE/OWN_HISTORY behavior is explained once instead of three times. - Cut the unsigned-history warning note from a paragraph to one line.

nelson-parente mentioned this pull request May 19, 2026

feat(dotnet): workflow context propagation quickstart #1310

Open

7 tasks

nelson-parente marked this pull request as ready for review May 21, 2026 09:54

nelson-parente requested review from a team as code owners May 21, 2026 09:54

Merge branch 'master' into feat/wf-ctx-propagation-python

b86f2ba

nelson-parente changed the title ~~[DRAFT] feat(python): workflow context propagation quickstart~~ feat(python): workflow context propagation quickstart May 21, 2026

javier-aliaga mentioned this pull request May 27, 2026

v1.18 Endgame dapr/dapr#9856

Open

nelson-parente changed the base branch from master to release-1.18 May 28, 2026 21:26

alicejgibbons requested changes May 29, 2026

View reviewed changes

alicejgibbons and others added 2 commits May 29, 2026 11:00

Merge branch 'release-1.18' into feat/wf-ctx-propagation-python

8413e05

docs(python): trim redundant README sections in history-propagation

5e9fa6b

- Merge 'Key demonstration' into 'Scenarios' so the LINEAGE/OWN_HISTORY behavior is explained once instead of three times. - Cut the unsigned-history warning note from a paragraph to one line.

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

feat(python): workflow context propagation quickstart#1309

feat(python): workflow context propagation quickstart#1309
nelson-parente wants to merge 7 commits into
dapr:release-1.18from
nelson-parente:feat/wf-ctx-propagation-python

nelson-parente commented May 19, 2026 •

edited

Loading

Uh oh!

nelson-parente commented May 28, 2026

Uh oh!

alicejgibbons left a comment

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

alicejgibbons May 29, 2026

Uh oh!

nelson-parente commented May 29, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

nelson-parente commented May 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Scenario

Two scenarios (matches the Go demo)

Python API used (from dapr/python-sdk#1025)

Replay safety

Files

Test plan

References

Uh oh!

nelson-parente commented May 28, 2026

Uh oh!

alicejgibbons left a comment

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

alicejgibbons May 29, 2026

Choose a reason for hiding this comment

Uh oh!

nelson-parente commented May 29, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

nelson-parente commented May 19, 2026 •

edited

Loading