CCM-12616: Added py-mock-mesh module

Author: gareth-allan

.gitignore

@@ -22,3 +22,10 @@ node_modules
 dist
 .DS_Store
 .reports
+
+# Don't track ephemeral local build files
+.turbo
+target/
+
+# Ignore coverage files
+.coverage

.gitleaksignore

@@ -4,3 +4,4 @@ cd9c0efec38c5d63053dd865e5d4e207c0760d91:docs/guides/Perform_static_analysis.md:
 cd9c0efec38c5d63053dd865e5d4e207c0760d91:docs/guides/Perform_static_analysis.md:sonar-api-token:37
 96096685ab3d6876671e2bc9a6ff4d48fc56e521:src/helloworld/helloworld.sln:ipv4:4
 4f4e8c15629b2cb09356a7fed4d72953590227ce:docs/Gemfile.lock:ipv4:4
+52386bca9b88c0c8c7dee52ab0ec69d04fb72c46:src/TESTING_PLAN.md:ipv4:145

.tool-versions

@@ -3,12 +3,12 @@ gitleaks 8.24.0
 jq 1.6
 nodejs 22.11.0
 pre-commit 3.6.0
+python 3.13.2
 terraform 1.10.1
 terraform-docs 0.19.0
 trivy 0.61.0
 vale 3.6.0
-
-
+poetry 1.8.3
 # ==============================================================================
 # The section below is reserved for Docker image versions.
 

docs/Gemfile.lock

@@ -28,9 +28,13 @@ GEM
     erb (4.0.4)
       cgi (>= 0.3.3)
     eventmachine (1.2.7)
+    ffi (1.17.2-arm64-darwin)
     ffi (1.17.2-x86_64-linux-gnu)
     forwardable-extended (2.6.0)
     gemoji (4.1.0)
+    google-protobuf (4.32.1-arm64-darwin)
+      bigdecimal
+      rake (>= 13)
     google-protobuf (4.32.1-x86_64-linux-gnu)
       bigdecimal
       rake (>= 13)
@@ -103,6 +107,8 @@ GEM
     mercenary (0.4.0)
     minitest (5.24.1)
     mutex_m (0.2.0)
+    nokogiri (1.18.9-arm64-darwin)
+      racc (~> 1.4)
     nokogiri (1.18.9-x86_64-linux-gnu)
       racc (~> 1.4)
     parallel (1.27.0)
@@ -138,6 +144,8 @@ GEM
       prism (~> 1.4)
     ruby-progressbar (1.13.0)
     safe_yaml (1.0.5)
+    sass-embedded (1.78.0-arm64-darwin)
+      google-protobuf (~> 4.27)
     sass-embedded (1.78.0-x86_64-linux-gnu)
       google-protobuf (~> 4.27)
     terminal-table (3.0.2)
@@ -148,6 +156,7 @@ GEM
     webrick (1.9.1)
 
 PLATFORMS
+  arm64-darwin-25
   x86_64-linux
 
 DEPENDENCIES

infrastructure/terraform/components/dl/module_lambda_mesh_poll.tf

@@ -54,4 +54,18 @@ data "aws_iam_policy_document" "mesh_poll_lambda" {
       module.kms.key_arn,
     ]
   }
+
+  statement {
+    sid    = "LettersBucketPermissions"
+    effect = "Allow"
+
+    actions = [
+      "s3:ListBucket",
+      "s3:GetObject",
+    ]
+
+    resources = [
+      "${module.s3bucket_letters.arn}/mock-mesh/*",
+    ]
+  }
 }

utils/py-mock-mesh/Makefile

@@ -0,0 +1,25 @@
+PACKAGE=py_mock_mesh
+VERSION=1.0.0
+
+audit:
+	poetry run python -m jake.app ddt -t POETRY -f poetry.lock
+
+install:
+	poetry install
+
+test:
+	poetry run pytest || echo
+
+test-coverage:
+	poetry run pytest --cov --cov-report xml:target/coverage/@comms/py-mock-mesh/cobertura-coverage.xml || echo
+
+lint:
+	poetry run pylint py_mock_mesh
+
+format:
+	poetry run autopep8 -ri .
+
+clean:
+	rm -rf target
+
+.PHONY: audit install test test-coverage lint format clean

utils/py-mock-mesh/README.md

@@ -0,0 +1,22 @@
+# py-mock-mesh
+
+## Overview
+
+The py-mock-mesh library provides a mock implementation of the NHS Notify MESH API using AWS S3, allowing developers to simulate interactions with the MESH service for testing and development purposes.
+
+This library does the following:
+
+- Simulates the sending and receiving of messages via the MESH API.
+- Stores messages in AWS S3 buckets for retrieval and processing.
+- Provides endpoints to interact with the mock MESH service.
+- Supports testing of MESH API integrations without needing access to the live service.
+- Facilitates development by mimicking the behaviour of the actual MESH service.
+- Ensures compatibility with existing MESH API clients.
+- Allows configuration of message delivery delays and errors for testing purposes.
+- Includes logging and monitoring features for debugging and analysis.
+
+## Sending and Receiving Messages
+
+1. Upload the to the S3 bucket by running this command: `aws s3 cp --metadata <field>=<value>,<field2>=<value2> <input_file> <target_path>`. Note: the target path should be the `nhs-<account>-<region>-<environment>-dl-letters` bucket for your environment. For example: the target path would be `s3://nhs-123456789012-eu-west-2-pr42-dl-letters/mock-mesh/<target-mailbox>/in/<key>`. The key is what the file will be saved as in the AWS S3 bucket, this is a string.
+2. The MESH poll lambda can be invoked early by pressing 'Test' in the AWS console. Alternatively, the lambda polls the mailbox every 30 minutes.
+3. To check for any errors and troubleshoot or that the message has been sent successfully, check the logs in the lambdas in the following order: MESH poller lambda, then the MESH retriever lambda.

utils/py-mock-mesh/package.json

@@ -0,0 +1,15 @@
+{
+  "description": "python library to simulate mesh with an s3 backend",
+  "name": "@comms/py-mock-mesh",
+  "private": true,
+  "scripts": {
+    "audit": "make audit",
+    "lint": "make lint",
+    "lint:fmt": "make format",
+    "python-install": "make install",
+    "test:unit": "make test",
+    "test:unit:coverage": "make test-coverage",
+    "typecheck": "echo this package contains no typescript"
+  },
+  "version": "1.0.0"
+}