Update c7n logging for base64 decode error for clarification

[liz-acosta]

Describe the bug

c7n-mailer supports KMS encryption of Slack tokens and other mailer config secrets and will attempt to handle the secret accordingly. However, this is not always the user's intention and the error log that occurs as a result of a failed attempted unnecessary decryption lacks clarity.

So even though my intention is plaintext, the log reads as an error:

Error: Incorrect padding Unable to base64 decode slack_token, will assume plaintext.

What did you expect to happen?

I was expecting more information and clarity that I can use for debugging if necessary.

Cloud Provider

Amazon Web Services (AWS)

Cloud Custodian version and dependency information

Custodian:   0.9.15
Python:      3.10.2 (main, Feb  2 2022, 08:42:42) [Clang 13.0.0 (clang-1300.0.29.3)]
Platform:    posix.uname_result(sysname='Darwin', nodename='all-computers-are-broken.local', release='20.5.0', version='Darwin Kernel Version 20.5.0: Sat May  8 05:10:33 PDT 2021; root:xnu-7195.121.3~9/RELEASE_X86_64', machine='x86_64')
Using venv:  True
Docker: False
Installed: 

PyJWT==1.7.1
PyYAML==6.0
adal==1.2.7
appdirs==1.4.4
applicationinsights==0.11.10
apscheduler==3.8.1
argcomplete==2.0.0
attrs==21.4.0
azure-common==1.1.28
azure-core==1.22.1
azure-cosmos==3.2.0
azure-cosmosdb-nspkg==2.0.2
azure-cosmosdb-table==1.0.6
azure-functions==1.9.0
azure-graphrbac==0.61.1
azure-identity==1.7.1
azure-keyvault==4.1.0
azure-keyvault-certificates==4.3.0
azure-keyvault-keys==4.4.0
azure-keyvault-secrets==4.3.0
azure-mgmt-advisor==9.0.0
azure-mgmt-apimanagement==1.0.0
azure-mgmt-applicationinsights==1.0.0
azure-mgmt-authorization==1.0.0
azure-mgmt-batch==15.0.0
azure-mgmt-cdn==10.0.0
azure-mgmt-cognitiveservices==11.0.0
azure-mgmt-compute==19.0.0
azure-mgmt-containerinstance==7.0.0
azure-mgmt-containerregistry==8.0.0b1
azure-mgmt-containerservice==15.1.0
azure-mgmt-core==1.3.0
azure-mgmt-cosmosdb==6.4.0
azure-mgmt-costmanagement==1.0.0
azure-mgmt-databricks==1.0.0b1
azure-mgmt-datafactory==1.1.0
azure-mgmt-datalake-store==1.0.0
azure-mgmt-dns==8.0.0b1
azure-mgmt-eventgrid==8.0.0
azure-mgmt-eventhub==8.0.0
azure-mgmt-frontdoor==1.0.0
azure-mgmt-hdinsight==7.0.0
azure-mgmt-iothub==1.0.0
azure-mgmt-keyvault==8.0.0
azure-mgmt-logic==9.0.0
azure-mgmt-managementgroups==1.0.0b1
azure-mgmt-monitor==2.0.0
azure-mgmt-msi==1.0.0
azure-mgmt-network==17.1.0
azure-mgmt-policyinsights==1.0.0
azure-mgmt-rdbms==8.1.0
azure-mgmt-redis==12.0.0
azure-mgmt-resource==16.1.0
azure-mgmt-resourcegraph==7.0.0
azure-mgmt-search==8.0.0
azure-mgmt-security==1.0.0
azure-mgmt-servicefabric==1.0.0
azure-mgmt-sql==1.0.0
azure-mgmt-storage==17.1.0
azure-mgmt-subscription==1.0.0
azure-mgmt-trafficmanager==0.51.0
azure-mgmt-web==2.0.0
azure-nspkg==3.0.2
azure-storage-blob==12.9.0
azure-storage-common==2.1.0
azure-storage-file==2.1.0
azure-storage-file-share==12.6.0
azure-storage-queue==12.1.6
boto3==1.21.5
botocore==1.24.5
cachetools==5.0.0
certifi==2021.10.8
cffi==1.15.0
charset-normalizer==2.0.12
click==8.0.4
cryptography==36.0.1
decorator==5.1.1
distlib==0.3.4
docutils==0.17.1
dogpile.cache==1.1.5
google-api-core==2.5.0
google-api-python-client==2.37.0
google-auth==2.6.0
google-auth-httplib2==0.1.0
google-cloud-appengine-logging==1.1.0
google-cloud-audit-log==0.2.0
google-cloud-core==2.2.2
google-cloud-logging==2.7.0
google-cloud-monitoring==2.8.0
google-cloud-storage==1.44.0
google-crc32c==1.3.0
google-resumable-media==2.2.1
googleapis-common-protos==1.54.0
grpc-google-iam-v1==0.12.3
grpcio==1.44.0
httplib2==0.20.4
idna==3.3
importlib-metadata==4.11.1
iso8601==1.0.2
isodate==0.6.1
jmespath==0.10.0
jsonpatch==1.32
jsonpointer==2.2
jsonschema==4.4.0
keystoneauth1==4.4.0
kubernetes==10.0.1
mock==4.0.3
msal==1.17.0
msal-extensions==0.3.1
msrest==0.6.21
msrestazure==0.6.4
munch==2.5.0
netaddr==0.7.20
netifaces==0.11.0
oauthlib==3.2.0
openstacksdk==0.52.0
os-service-types==1.7.0
packaging==21.3
pbr==5.8.1
portalocker==2.4.0
proto-plus==1.20.3
protobuf==3.19.4
pyasn1==0.4.8
pyasn1-modules==0.2.8
pycparser==2.21
pyparsing==3.0.7
pyrsistent==0.18.1
python-dateutil==2.8.2
pytz==2021.3
pytz-deprecation-shim==0.1.0.post0
pyyaml==6.0
ratelimiter==1.2.0.post0
requests==2.27.1
requests-oauthlib==1.3.1
requestsexceptions==1.4.0
retrying==1.3.3
rsa==4.8
s3transfer==0.5.1
setuptools==58.3.0
six==1.16.0
stevedore==3.5.0
tabulate==0.8.9
tzdata==2021.5
tzlocal==4.1
uritemplate==4.1.1
urllib3==1.26.8
websocket-client==1.2.3
zipp==3.7.0

Policy

queue_url: https://sqs.us-east-1.amazonaws.com/<account_number>/c7n-102-mailer-queue
role: arn:aws:iam::<account_number>:role/c7n-102-execution-role
slack_token: <slack_token>
lambda_tags:
  c7n-102: ""

Relevant log/traceback output

No response

Extra information or context

Spoke with @ajkerrigan about this as well and this was partly his suggestion : )