make use of environment config

.gitignore

@@ -1 +1,3 @@
-/.direnv
+/.direnv
+/dist
+/package.zip

.pylintrc

@@ -1,2 +1,3 @@
 [MAIN]
-max-line-length=120
+max-line-length=120
+max-args=7

Makefile

@@ -7,4 +7,13 @@ format:
 test:
 	black -l 120 --check -t py311 .
 	pylint main.py
-
+
+clean:
+	rm -rf dist
+	rm -f package.zip
+
+build: clean test
+	mkdir dist
+	pip install --target ./dist -r requirements.txt
+	cd dist; zip -r ../package.zip .
+	zip package.zip main.py

README.md

@@ -1,2 +1,31 @@
 # rds-backup-lambda
-Small lambda function to copy automated RDS snapshots into another region
+
+Small AWS Lambda function to copy automated RDS snapshots into another region.
+
+## Installation
+
+Create a AWS lambda function in your prefered region. Add the following environment configuration:
+
+
+```
+# AWS account ID
+ACCOUNT = "1234567890"
+# Region where the automated snapshots are located
+SOURCE_REGION = "eu-west-1"
+# Region where the automated snapshots should be copied to
+TARGET_REGION = "eu-central-1"
+# Comma separated list of RDS instances which snapshots should be copied
+SOURCE_DB = "my-rds-instance"
+# Comma-separated list of RDS clusters which snapshots should be copied
+SOURCE_CLUSTER = "my-aurora-cluster"
+# KMS Key in target region to use for snapshot encryption
+DEST_KMS = "arn:aws:kms:eu-central-1:1234567890:key/abc123"
+# Number of snapshots to keep
+KEEP_SNAPSHOTS = 10
+```
+
+Create a `package.zip` for uploading as code:
+
+```
+make build
+```

main.py

@@ -9,17 +9,7 @@
 
 import boto3
 import botocore
-
-# Region where the automated snapshots are located
-SOURCE_REGION = "eu-west-1"
-# List of RDS instances which snapshots should be copied
-SOURCE_DB = ["my-rds-instance"]
-# List of RDS clusters which snapshots should be copied
-SOURCE_CLUSTER = ["my-aurora-cluster", "my-second-cluster"]
-# KMS Key in target region to use for Aurora Cluster Snapshots
-DEST_KMS = "arn:aws:kms:eu-central-1:ABC123:key/abc123"
-# Number of snapshots to keep
-KEEP = 10
+from environs import Env
 
 
 class BackupException(Exception):
@@ -51,7 +41,7 @@ def by_timestamp(snap):
     return datetime.datetime.isoformat(datetime.datetime.now())
 
 
-def copy_rds_snapshots(source_client, target_client, account, name):
+def copy_rds_snapshots(source_client, target_client, source_region, account, name, kms, keep):
     """
     Copies snapshots from an RDS instance
     """
@@ -64,32 +54,32 @@ def copy_rds_snapshots(source_client, target_client, account, name):
         return
 
     source_snap = sorted(source_snaps, key=by_snapshot_id, reverse=True)[0]["DBSnapshotIdentifier"]
-    source_snap_arn = f"arn:aws:rds:{SOURCE_REGION}:{account}:snapshot:{source_snap}"
+    source_snap_arn = f"arn:aws:rds:{source_region}:{account}:snapshot:{source_snap}"
     target_snap_id = f"copy-of-{re.sub('rds:', '', source_snap)}"
     print(f"Will copy {source_snap_arn} to {target_snap_id}")
 
     try:
         target_client.copy_db_snapshot(
             SourceDBSnapshotIdentifier=source_snap_arn,
             TargetDBSnapshotIdentifier=target_snap_id,
-            KmsKeyId=DEST_KMS,
+            KmsKeyId=kms,
             CopyTags=True,
-            SourceRegion=SOURCE_REGION,
+            SourceRegion=source_region,
         )
     except botocore.exceptions.ClientError as ex:
         raise BackupException(f"Could not issue copy command: {ex}") from ex
 
     copied_snaps = target_client.describe_db_snapshots(SnapshotType="manual", DBInstanceIdentifier=name)["DBSnapshots"]
-    if len(copied_snaps) > KEEP:
-        for snap in sorted(copied_snaps, key=by_timestamp, reverse=True)[KEEP:]:
+    if len(copied_snaps) > keep:
+        for snap in sorted(copied_snaps, key=by_timestamp, reverse=True)[keep:]:
             print(f"Will remove {snap['DBSnapshotIdentifier']}")
             try:
                 target_client.delete_db_snapshot(DBSnapshotIdentifier=snap["DBSnapshotIdentifier"])
             except botocore.exceptions.ClientError as ex:
                 raise BackupException(f"Could not delete snapshot {snap['DBSnapshotIdentifier']}: {ex}") from ex
 
 
-def copy_cluster_snapshots(source_client, target_client, account, cluster_name):
+def copy_cluster_snapshots(source_client, target_client, source_region, account, cluster_name, kms, keep):
     """
     Coppies snapshots from a RDS cluster
     """
@@ -101,22 +91,22 @@ def copy_cluster_snapshots(source_client, target_client, account, cluster_name):
         print("Found no automated snapshots. Nothing to do")
         return
     source_snap = sorted(source_snaps, key=by_cluster_snapshot_id, reverse=True)[0]["DBClusterSnapshotIdentifier"]
-    source_snap_arn = f"arn:aws:rds:{SOURCE_REGION}:{account}:cluster-snapshot:{source_snap}"
+    source_snap_arn = f"arn:aws:rds:{source_region}:{account}:cluster-snapshot:{source_snap}"
     target_snap_id = f"copy-of-{re.sub('rds:', '', source_snap)}"
     print(f"Will copy {source_snap_arn} to {target_snap_id}")
 
     target_client.copy_db_cluster_snapshot(
         SourceDBClusterSnapshotIdentifier=source_snap_arn,
         TargetDBClusterSnapshotIdentifier=target_snap_id,
-        KmsKeyId=DEST_KMS,
-        SourceRegion=SOURCE_REGION,
+        KmsKeyId=kms,
+        SourceRegion=source_region,
     )
 
     copied_snaps = target_client.describe_db_cluster_snapshots(SnapshotType="manual", DBClusterIdentifier=cluster_name)[
         "DBClusterSnapshots"
     ]
-    if len(copied_snaps) > KEEP:
-        for snap in sorted(copied_snaps, key=by_timestamp, reverse=True)[KEEP:]:
+    if len(copied_snaps) > keep:
+        for snap in sorted(copied_snaps, key=by_timestamp, reverse=True)[keep:]:
             snap_id = snap["DBClusterSnapshotIdentifier"]
             print(f"Will remove {snap_id}")
             try:
@@ -125,18 +115,27 @@ def copy_cluster_snapshots(source_client, target_client, account, cluster_name):
                 raise BackupException(f"Could not delete snapshot {snap_id}: {ex}") from ex
 
 
-def lambda_handler(event, context):
+def lambda_handler(event, context):  # pylint: disable=unused-argument
     """
     Entrypoint for AWS Lambda
     """
-    if context:
-        print(f"Starting '{context.function_name}' version {context.function_version}")
 
-    target_region = event["region"]
-    account = event["account"]
-    source_client = boto3.client("rds", region_name=SOURCE_REGION)
+    # Get config from environment
+    env = Env()
+    source_region = env.str("SOURCE_REGION")
+    source_db = env.list("SOURCE_DB", [])
+    source_cluster = env.list("SOURCE_CLUSTER", [])
+    dest_kms = env.str("DEST_KMS", "")
+    keep_snapshots = env.int("KEEP_SNAPSHOTS", 1)
+    target_region = env.str("TARGET_REGION")
+    account = env.str("AWS_ACCOUNT")
+
+    # Create clients
+    source_client = boto3.client("rds", region_name=source_region)
     target_client = boto3.client("rds", region_name=target_region)
-    for name in SOURCE_DB:
-        copy_rds_snapshots(source_client, target_client, account, name)
-    for name in SOURCE_CLUSTER:
-        copy_cluster_snapshots(source_client, target_client, account, name)
+
+    for name in source_db:
+        copy_rds_snapshots(source_client, target_client, source_region, account, name, dest_kms, keep_snapshots)
+
+    for name in source_cluster:
+        copy_cluster_snapshots(source_client, target_client, source_region, account, name, dest_kms, keep_snapshots)

requirements.txt

@@ -1,2 +1,3 @@
 boto3
 botocore
+environs

shell.nix

@@ -3,8 +3,11 @@
 pkgs.mkShell {
   buildInputs = with pkgs; [
     black
+    python311Packages.pip
     python311Packages.pylint
     python311Packages.botocore
     python311Packages.boto3
+    python311Packages.environs
+    zip
   ];
 }