apm-wo-analysis/tests/test_grafana_synth.py

"""Synth-level assertions for the Grafana stack (Phase 5).

Synthesizes ``apm-wo-analysis-grafana`` and asserts the security posture that
can't be eyeballed: the ALB only admits the office CIDRs on 443 (never
0.0.0.0/0), the instance only takes traffic from the ALB SG, the instance role
carries no static keys and only scoped Athena/Glue-read/S3 access, the root
volume is gp3 + retained, a daily DLM backup exists, and grafana.seahaven.com
aliases the ALB. No AWS, no Docker (bundling skipped).

Run with the repo venv:

    python -m pytest tests/test_grafana_synth.py -q
"""

import json
import sys
from pathlib import Path

import aws_cdk as cdk
from aws_cdk.assertions import Match, Template

CDK_DIR = Path(__file__).resolve().parents[1] / "cdk"
sys.path.insert(0, str(CDK_DIR))

from stacks.grafana_stack import GrafanaStack  # noqa: E402

OFFICE_CIDRS = {"47.21.61.4/32", "96.250.164.146/32"}


def _cdk_context() -> dict:
    ctx = json.loads((CDK_DIR / "cdk.json").read_text())["context"]
    ctx["aws:cdk:bundling-stacks"] = []
    return ctx


def _template() -> Template:
    app = cdk.App(context=_cdk_context())
    stack = GrafanaStack(
        app,
        "apm-wo-analysis-grafana",
        env=cdk.Environment(account="328440206208", region="us-east-1"),
    )
    return Template.from_stack(stack)


def _all_cidr_ingress(t: Template):
    """Every CIDR-based ingress rule, inline on SGs and standalone, as
    (cidr, from_port, to_port) tuples."""
    rules = []
    for sg in t.find_resources("AWS::EC2::SecurityGroup").values():
        for r in sg["Properties"].get("SecurityGroupIngress", []):
            if "CidrIp" in r:
                rules.append((r["CidrIp"], r.get("FromPort"), r.get("ToPort")))
    for ing in t.find_resources("AWS::EC2::SecurityGroupIngress").values():
        p = ing["Properties"]
        if "CidrIp" in p:
            rules.append((p["CidrIp"], p.get("FromPort"), p.get("ToPort")))
    return rules


def test_alb_only_admits_office_cidrs_on_443():
    rules = _all_cidr_ingress(_template())
    cidrs_443 = {c for c, fp, tp in rules if fp == 443 and tp == 443}
    assert cidrs_443 == OFFICE_CIDRS, (
        f"443 ingress should be office-only, got {cidrs_443}"
    )
    # Nothing anywhere may be open to the world.
    assert all(c != "0.0.0.0/0" for c, _, _ in rules), "found a 0.0.0.0/0 ingress"


def test_instance_only_reachable_from_alb_on_3000():
    # The instance SG ingress on 3000 is a SourceSecurityGroup rule, not a CIDR.
    _template().has_resource_properties(
        "AWS::EC2::SecurityGroupIngress",
        Match.object_like(
            {
                "FromPort": 3000,
                "ToPort": 3000,
                "SourceSecurityGroupId": Match.any_value(),
            }
        ),
    )


def test_alb_internet_facing_https_listener():
    t = _template()
    t.has_resource_properties(
        "AWS::ElasticLoadBalancingV2::LoadBalancer", {"Scheme": "internet-facing"}
    )
    t.has_resource_properties(
        "AWS::ElasticLoadBalancingV2::Listener",
        Match.object_like(
            {"Port": 443, "Protocol": "HTTPS", "Certificates": Match.any_value()}
        ),
    )


def test_no_static_keys_in_stack():
    t = _template()
    t.resource_count_is("AWS::IAM::User", 0)
    t.resource_count_is("AWS::IAM::AccessKey", 0)


def test_instance_role_scoped_and_uses_ssm():
    t = _template()
    # Session Manager (no SSH) — the SSM managed policy is attached.
    t.has_resource_properties(
        "AWS::IAM::Role",
        Match.object_like(
            {
                "ManagedPolicyArns": Match.array_with(
                    [
                        {
                            "Fn::Join": [
                                "",
                                Match.array_with(
                                    [":iam::aws:policy/AmazonSSMManagedInstanceCore"]
                                ),
                            ]
                        }
                    ]
                )
            }
        ),
    )
    # The instance role must not be able to write the catalog or run wide Athena.
    for policy in t.find_resources("AWS::IAM::Policy").values():
        for stmt in policy["Properties"]["PolicyDocument"]["Statement"]:
            actions = stmt.get("Action", [])
            actions = [actions] if isinstance(actions, str) else actions
            for a in actions:
                if isinstance(a, str):
                    assert a not in ("glue:*", "athena:*", "s3:*", "*"), (
                        f"too broad: {a}"
                    )
                    assert not a.startswith("glue:Create"), f"no Glue writes: {a}"
                    assert not a.startswith("glue:Update"), f"no Glue writes: {a}"


def test_root_volume_gp3_and_retained():
    _template().has_resource_properties(
        "AWS::EC2::Instance",
        Match.object_like(
            {
                "BlockDeviceMappings": Match.array_with(
                    [
                        Match.object_like(
                            {
                                "Ebs": Match.object_like(
                                    {"VolumeType": "gp3", "DeleteOnTermination": False}
                                )
                            }
                        )
                    ]
                )
            }
        ),
    )


def test_daily_dlm_backup_enabled():
    _template().has_resource_properties(
        "AWS::DLM::LifecyclePolicy",
        Match.object_like(
            {
                "State": "ENABLED",
                "PolicyDetails": Match.object_like({"ResourceTypes": ["INSTANCE"]}),
            }
        ),
    )


def test_route53_alias_for_grafana():
    _template().has_resource_properties(
        "AWS::Route53::RecordSet",
        Match.object_like({"Type": "A", "Name": "grafana.seahaven.com."}),
    )