Package software.amazon.awscdk.services.logs
Amazon CloudWatch Logs Construct Library
This library supplies constructs for working with CloudWatch Logs.
Log Groups/Streams
The basic unit of CloudWatch is a Log Group. Every log group typically has the same kind of data logged to it, in the same format. If there are multiple applications or services logging into the Log Group, each of them creates a new Log Stream.
Every log operation creates a "log event", which can consist of a simple string or a single-line JSON object. JSON objects have the advantage that they afford more filtering abilities (see below).
The only configurable attribute for log streams is the retention period, which configures after how much time the events in the log stream expire and are deleted.
The default retention period if not supplied is 2 years, but it can be set to
one of the values in the RetentionDays
enum to configure a different
retention period (including infinite retention).
// Configure log group for short retention LogGroup logGroup = LogGroup.Builder.create(stack, "LogGroup") .retention(RetentionDays.ONE_WEEK) .build();// Configure log group for infinite retention LogGroup logGroup = LogGroup.Builder.create(stack, "LogGroup") .retention(Infinity) .build();
LogRetention
The LogRetention
construct is a way to control the retention period of log groups that are created outside of the CDK. The construct is usually
used on log groups that are auto created by AWS services, such as AWS
lambda.
This is implemented using a CloudFormation custom resource which pre-creates the log group if it doesn't exist, and sets the specified log retention period (never expire, by default).
By default, the log group will be created in the same region as the stack. The logGroupRegion
property can be used to configure
log groups in other regions. This is typically useful when controlling retention for log groups auto-created by global services that
publish their log group to a specific region, such as AWS Chatbot creating a log group in us-east-1
.
By default, the log group created by LogRetention will be retained after the stack is deleted. If the RemovalPolicy is set to DESTROY, then the log group will be deleted when the stack is deleted.
Log Group Class
CloudWatch Logs offers two classes of log groups:
- The CloudWatch Logs Standard log class is a full-featured option for logs that require real-time monitoring or logs that you access frequently.
- The CloudWatch Logs Infrequent Access log class is a new log class that you can use to cost-effectively consolidate your logs. This log class offers a subset of CloudWatch Logs capabilities including managed ingestion, storage, cross-account log analytics, and encryption with a lower ingestion price per GB. The Infrequent Access log class is ideal for ad-hoc querying and after-the-fact forensic analysis on infrequently accessed logs.
For more details please check: log group class documentation
Resource Policy
CloudWatch Resource Policies allow other AWS services or IAM Principals to put log events into the log groups.
A resource policy is automatically created when addToResourcePolicy
is called on the LogGroup for the first time:
LogGroup logGroup = new LogGroup(this, "LogGroup"); logGroup.addToResourcePolicy(PolicyStatement.Builder.create() .actions(List.of("logs:CreateLogStream", "logs:PutLogEvents")) .principals(List.of(new ServicePrincipal("es.amazonaws.com"))) .resources(List.of(logGroup.getLogGroupArn())) .build());
Or more conveniently, write permissions to the log group can be granted as follows which gives same result as in the above example.
LogGroup logGroup = new LogGroup(this, "LogGroup"); logGroup.grantWrite(new ServicePrincipal("es.amazonaws.com"));
Similarly, read permissions can be granted to the log group as follows.
LogGroup logGroup = new LogGroup(this, "LogGroup"); logGroup.grantRead(new ServicePrincipal("es.amazonaws.com"));
Be aware that any ARNs or tokenized values passed to the resource policy will be converted into AWS Account IDs. This is because CloudWatch Logs Resource Policies do not accept ARNs as principals, but they do accept Account ID strings. Non-ARN principals, like Service principals or Any principals, are accepted by CloudWatch.
Encrypting Log Groups
By default, log group data is always encrypted in CloudWatch Logs. You have the option to encrypt log group data using a AWS KMS customer master key (CMK) should you not wish to use the default AWS encryption. Keep in mind that if you decide to encrypt a log group, any service or IAM identity that needs to read the encrypted log streams in the future will require the same CMK to decrypt the data.
Here's a simple example of creating an encrypted Log Group using a KMS CMK.
import software.amazon.awscdk.services.kms.*; LogGroup.Builder.create(this, "LogGroup") .encryptionKey(new Key(this, "Key")) .build();
See the AWS documentation for more detailed information about encrypting CloudWatch Logs.
Subscriptions and Destinations
Log events matching a particular filter can be sent to either a Lambda function or a Kinesis stream.
If the Kinesis stream lives in a different account, a CrossAccountDestination
object needs to be added in the destination account which will act as a proxy
for the remote Kinesis stream. This object is automatically created for you
if you use the CDK Kinesis library.
Create a SubscriptionFilter
, initialize it with an appropriate Pattern
(see
below) and supply the intended destination:
import software.amazon.awscdk.services.logs.destinations.*; Function fn; LogGroup logGroup; SubscriptionFilter.Builder.create(this, "Subscription") .logGroup(logGroup) .destination(new LambdaDestination(fn)) .filterPattern(FilterPattern.allTerms("ERROR", "MainThread")) .filterName("ErrorInMainThread") .build();
When you use KinesisDestination
, you can choose the method used to
distribute log data to the destination by setting the distribution
property.
import software.amazon.awscdk.services.logs.destinations.*; import software.amazon.awscdk.services.kinesis.*; Stream stream; LogGroup logGroup; SubscriptionFilter.Builder.create(this, "Subscription") .logGroup(logGroup) .destination(new KinesisDestination(stream)) .filterPattern(FilterPattern.allTerms("ERROR", "MainThread")) .filterName("ErrorInMainThread") .distribution(Distribution.RANDOM) .build();
Metric Filters
CloudWatch Logs can extract and emit metrics based on a textual log stream. Depending on your needs, this may be a more convenient way of generating metrics for you application than making calls to CloudWatch Metrics yourself.
A MetricFilter
either emits a fixed number every time it sees a log event
matching a particular pattern (see below), or extracts a number from the log
event and uses that as the metric value.
Example:
MetricFilter.Builder.create(this, "MetricFilter") .logGroup(logGroup) .metricNamespace("MyApp") .metricName("Latency") .filterPattern(FilterPattern.exists("$.latency")) .metricValue("$.latency") .build();
Remember that if you want to use a value from the log event as the metric value, you must mention it in your pattern somewhere.
A very simple MetricFilter can be created by using the logGroup.extractMetric()
helper function:
LogGroup logGroup; logGroup.extractMetric("$.jsonField", "Namespace", "MetricName");
Will extract the value of jsonField
wherever it occurs in JSON-structured
log records in the LogGroup, and emit them to CloudWatch Metrics under
the name Namespace/MetricName
.
Exposing Metric on a Metric Filter
You can expose a metric on a metric filter by calling the MetricFilter.metric()
API.
This has a default of statistic = 'avg'
if the statistic is not set in the props
.
LogGroup logGroup; MetricFilter mf = MetricFilter.Builder.create(this, "MetricFilter") .logGroup(logGroup) .metricNamespace("MyApp") .metricName("Latency") .filterPattern(FilterPattern.exists("$.latency")) .metricValue("$.latency") .dimensions(Map.of( "ErrorCode", "$.errorCode")) .unit(Unit.MILLISECONDS) .build(); //expose a metric from the metric filter Metric metric = mf.metric(); //you can use the metric to create a new alarm //you can use the metric to create a new alarm Alarm.Builder.create(this, "alarm from metric filter") .metric(metric) .threshold(100) .evaluationPeriods(2) .build();
Patterns
Patterns describe which log events match a subscription or metric filter. There are three types of patterns:
- Text patterns
- JSON patterns
- Space-delimited table patterns
All patterns are constructed by using static functions on the FilterPattern
class.
In addition to the patterns above, the following special patterns exist:
FilterPattern.allEvents()
: matches all log events.FilterPattern.literal(string)
: if you already know what pattern expression to use, this function takes a string and will use that as the log pattern. For more information, see the Filter and Pattern Syntax.
Text Patterns
Text patterns match if the literal strings appear in the text form of the log line.
FilterPattern.allTerms(term, term, ...)
: matches if all of the given terms (substrings) appear in the log event.FilterPattern.anyTerm(term, term, ...)
: matches if all of the given terms (substrings) appear in the log event.FilterPattern.anyTermGroup([term, term, ...], [term, term, ...], ...)
: matches if all of the terms in any of the groups (specified as arrays) matches. This is an OR match.
Examples:
// Search for lines that contain both "ERROR" and "MainThread" IFilterPattern pattern1 = FilterPattern.allTerms("ERROR", "MainThread"); // Search for lines that either contain both "ERROR" and "MainThread", or // both "WARN" and "Deadlock". IFilterPattern pattern2 = FilterPattern.anyTermGroup(List.of("ERROR", "MainThread"), List.of("WARN", "Deadlock"));
JSON Patterns
JSON patterns apply if the log event is the JSON representation of an object (without any other characters, so it cannot include a prefix such as timestamp or log level). JSON patterns can make comparisons on the values inside the fields.
- Strings: the comparison operators allowed for strings are
=
and!=
. String values can start or end with a*
wildcard. - Numbers: the comparison operators allowed for numbers are
=
,!=
,<
,<=
,>
,>=
.
Fields in the JSON structure are identified by identifier the complete object as $
and then descending into it, such as $.field
or $.list[0].field
.
FilterPattern.stringValue(field, comparison, string)
: matches if the given field compares as indicated with the given string value.FilterPattern.numberValue(field, comparison, number)
: matches if the given field compares as indicated with the given numerical value.FilterPattern.isNull(field)
: matches if the given field exists and has the valuenull
.FilterPattern.notExists(field)
: matches if the given field is not in the JSON structure.FilterPattern.exists(field)
: matches if the given field is in the JSON structure.FilterPattern.booleanValue(field, boolean)
: matches if the given field is exactly the given boolean value.FilterPattern.all(jsonPattern, jsonPattern, ...)
: matches if all of the given JSON patterns match. This makes an AND combination of the given patterns.FilterPattern.any(jsonPattern, jsonPattern, ...)
: matches if any of the given JSON patterns match. This makes an OR combination of the given patterns.
Example:
// Search for all events where the component field is equal to // "HttpServer" and either error is true or the latency is higher // than 1000. JsonPattern pattern = FilterPattern.all(FilterPattern.stringValue("$.component", "=", "HttpServer"), FilterPattern.any(FilterPattern.booleanValue("$.error", true), FilterPattern.numberValue("$.latency", ">", 1000)));
Space-delimited table patterns
If the log events are rows of a space-delimited table, this pattern can be used to identify the columns in that structure and add conditions on any of them. The canonical example where you would apply this type of pattern is Apache server logs.
Text that is surrounded by "..."
quotes or [...]
square brackets will
be treated as one column.
FilterPattern.spaceDelimited(column, column, ...)
: construct aSpaceDelimitedTextPattern
object with the indicated columns. The columns map one-by-one the columns found in the log event. The string"..."
may be used to specify an arbitrary number of unnamed columns anywhere in the name list (but may only be specified once).
After constructing a SpaceDelimitedTextPattern
, you can use the following
two members to add restrictions:
pattern.whereString(field, comparison, string)
: add a string condition. The rules are the same as for JSON patterns.pattern.whereNumber(field, comparison, number)
: add a numerical condition. The rules are the same as for JSON patterns.
Multiple restrictions can be added on the same column; they must all apply.
Example:
// Search for all events where the component is "HttpServer" and the // result code is not equal to 200. SpaceDelimitedTextPattern pattern = FilterPattern.spaceDelimited("time", "component", "...", "result_code", "latency").whereString("component", "=", "HttpServer").whereNumber("result_code", "!=", 200);
Logs Insights Query Definition
Creates a query definition for CloudWatch Logs Insights.
Example:
QueryDefinition.Builder.create(this, "QueryDefinition") .queryDefinitionName("MyQuery") .queryString(QueryString.Builder.create() .fields(List.of("@timestamp", "@message")) .parseStatements(List.of("@message \"[*] *\" as loggingType, loggingMessage", "@message \"<*>: *\" as differentLoggingType, differentLoggingMessage")) .filterStatements(List.of("loggingType = \"ERROR\"", "loggingMessage = \"A very strange error occurred!\"")) .sort("@timestamp desc") .limit(20) .build()) .build();
Data Protection Policy
Creates a data protection policy and assigns it to the log group. A data protection policy can help safeguard sensitive data that's ingested by the log group by auditing and masking the sensitive log data. When a user who does not have permission to view masked data views a log event that includes masked data, the sensitive data is replaced by asterisks.
For more information, see Protect sensitive log data with masking.
For a list of types of managed identifiers that can be audited and masked, see Types of data that you can protect.
If a new identifier is supported but not yet in the DataIdentifiers
enum, the name of the identifier can be supplied as name
in the constructor instead.
To add a custom data identifier, supply a custom name
and regex
to the CustomDataIdentifiers
constructor.
For more information on custom data identifiers, see Custom data identifiers.
Each policy may consist of a log group, S3 bucket, and/or Firehose delivery stream audit destination.
Example:
import software.amazon.awscdk.services.kinesisfirehose.alpha.*; import software.amazon.awscdk.services.kinesisfirehose.destinations.alpha.*; LogGroup logGroupDestination = LogGroup.Builder.create(this, "LogGroupLambdaAudit") .logGroupName("auditDestinationForCDK") .build(); Bucket bucket = new Bucket(this, "audit-bucket"); S3Bucket s3Destination = new S3Bucket(bucket); DeliveryStream deliveryStream = DeliveryStream.Builder.create(this, "Delivery Stream") .destinations(List.of(s3Destination)) .build(); DataProtectionPolicy dataProtectionPolicy = DataProtectionPolicy.Builder.create() .name("data protection policy") .description("policy description") .identifiers(List.of(DataIdentifier.DRIVERSLICENSE_US, // managed data identifier new DataIdentifier("EmailAddress"), // forward compatibility for new managed data identifiers new CustomDataIdentifier("EmployeeId", "EmployeeId-\\d{9}"))) // custom data identifier .logGroupAuditDestination(logGroupDestination) .s3BucketAuditDestination(bucket) .deliveryStreamNameAuditDestination(deliveryStream.getDeliveryStreamName()) .build(); LogGroup.Builder.create(this, "LogGroupLambda") .logGroupName("cdkIntegLogGroup") .dataProtectionPolicy(dataProtectionPolicy) .build();
Notes
Be aware that Log Group ARNs will always have the string :*
appended to
them, to match the behavior of the CloudFormation AWS::Logs::LogGroup
resource.
-
ClassDescriptionCreates or updates an account-level data protection policy or subscription filter policy that applies to all log groups or a subset of log groups in the account.A fluent builder for
CfnAccountPolicy
.Properties for defining aCfnAccountPolicy
.A builder forCfnAccountPolicyProps
An implementation forCfnAccountPolicyProps
This structure contains information about one delivery in your account.A fluent builder forCfnDelivery
.This structure contains information about one delivery destination in your account.A fluent builder forCfnDeliveryDestination
.Properties for defining aCfnDeliveryDestination
.A builder forCfnDeliveryDestinationProps
An implementation forCfnDeliveryDestinationProps
Properties for defining aCfnDelivery
.A builder forCfnDeliveryProps
An implementation forCfnDeliveryProps
This structure contains information about one delivery source in your account.A fluent builder forCfnDeliverySource
.Properties for defining aCfnDeliverySource
.A builder forCfnDeliverySourceProps
An implementation forCfnDeliverySourceProps
The AWS::Logs::Destination resource specifies a CloudWatch Logs destination.A fluent builder forCfnDestination
.Properties for defining aCfnDestination
.A builder forCfnDestinationProps
An implementation forCfnDestinationProps
Creates or updates an anomaly detector that regularly scans one or more log groups and look for patterns and anomalies in the logs.A fluent builder forCfnLogAnomalyDetector
.Properties for defining aCfnLogAnomalyDetector
.A builder forCfnLogAnomalyDetectorProps
An implementation forCfnLogAnomalyDetectorProps
TheAWS::Logs::LogGroup
resource specifies a log group.A fluent builder forCfnLogGroup
.Properties for defining aCfnLogGroup
.A builder forCfnLogGroupProps
An implementation forCfnLogGroupProps
TheAWS::Logs::LogStream
resource specifies an Amazon CloudWatch Logs log stream in a specific log group.A fluent builder forCfnLogStream
.Properties for defining aCfnLogStream
.A builder forCfnLogStreamProps
An implementation forCfnLogStreamProps
TheAWS::Logs::MetricFilter
resource specifies a metric filter that describes how CloudWatch Logs extracts information from logs and transforms it into Amazon CloudWatch metrics.A fluent builder forCfnMetricFilter
.Specifies the CloudWatch metric dimensions to publish with this metric.A builder forCfnMetricFilter.DimensionProperty
An implementation forCfnMetricFilter.DimensionProperty
MetricTransformation
is a property of theAWS::Logs::MetricFilter
resource that describes how to transform log streams into a CloudWatch metric.A builder forCfnMetricFilter.MetricTransformationProperty
An implementation forCfnMetricFilter.MetricTransformationProperty
Properties for defining aCfnMetricFilter
.A builder forCfnMetricFilterProps
An implementation forCfnMetricFilterProps
Creates a query definition for CloudWatch Logs Insights.A fluent builder forCfnQueryDefinition
.Properties for defining aCfnQueryDefinition
.A builder forCfnQueryDefinitionProps
An implementation forCfnQueryDefinitionProps
Creates or updates a resource policy that allows other AWS services to put log events to this account.A fluent builder forCfnResourcePolicy
.Properties for defining aCfnResourcePolicy
.A builder forCfnResourcePolicyProps
An implementation forCfnResourcePolicyProps
TheAWS::Logs::SubscriptionFilter
resource specifies a subscription filter and associates it with the specified log group.A fluent builder forCfnSubscriptionFilter
.Properties for defining aCfnSubscriptionFilter
.A builder forCfnSubscriptionFilterProps
An implementation forCfnSubscriptionFilterProps
Example:A builder forColumnRestriction
An implementation forColumnRestriction
A new CloudWatch Logs Destination for use in cross-account scenarios.A fluent builder forCrossAccountDestination
.Properties for a CrossAccountDestination.A builder forCrossAccountDestinationProps
An implementation forCrossAccountDestinationProps
A custom data identifier.A data protection identifier.Creates a data protection policy for CloudWatch Logs log groups.A fluent builder forDataProtectionPolicy
.Properties for creating a data protection policy.A builder forDataProtectionPolicyProps
An implementation forDataProtectionPolicyProps
The method used to distribute log data to the destination.A collection of static methods to generate appropriate ILogPatterns.Interface for objects that can render themselves to log patterns.Internal default implementation forIFilterPattern
.A proxy class which represents a concrete javascript instance of this type.Internal default implementation forILogGroup
.A proxy class which represents a concrete javascript instance of this type.Internal default implementation forILogStream
.A proxy class which represents a concrete javascript instance of this type.Interface for classes that can be the destination of a log Subscription.Internal default implementation forILogSubscriptionDestination
.A proxy class which represents a concrete javascript instance of this type.Base class for patterns that only match JSON log events.Define a CloudWatch Log Group.A fluent builder forLogGroup
.Class of Log Group.Properties for a LogGroup.A builder forLogGroupProps
An implementation forLogGroupProps
Creates a custom resource to control the retention policy of a CloudWatch Logs log group.A fluent builder forLogRetention
.Construction properties for a LogRetention.A builder forLogRetentionProps
An implementation forLogRetentionProps
Retry options for all AWS API calls.A builder forLogRetentionRetryOptions
An implementation forLogRetentionRetryOptions
Define a Log Stream in a Log Group.A fluent builder forLogStream
.Properties for a LogStream.A builder forLogStreamProps
An implementation forLogStreamProps
Properties returned by a Subscription destination.A builder forLogSubscriptionDestinationConfig
An implementation forLogSubscriptionDestinationConfig
A filter that extracts information from CloudWatch Logs and emits to CloudWatch Metrics.A fluent builder forMetricFilter
.Properties for a MetricFilter created from a LogGroup.A builder forMetricFilterOptions
An implementation forMetricFilterOptions
Properties for a MetricFilter.A builder forMetricFilterProps
An implementation forMetricFilterProps
Define a query definition for CloudWatch Logs Insights.A fluent builder forQueryDefinition
.Properties for a QueryDefinition.A builder forQueryDefinitionProps
An implementation forQueryDefinitionProps
Define a QueryString.A fluent builder forQueryString
.Properties for a QueryString.A builder forQueryStringProps
An implementation forQueryStringProps
Resource Policy for CloudWatch Log Groups.A fluent builder forResourcePolicy
.Properties to define Cloudwatch log group resource policy.A builder forResourcePolicyProps
An implementation forResourcePolicyProps
How long, in days, the log contents will be retained.Space delimited text pattern.Properties for a new LogStream created from a LogGroup.A builder forStreamOptions
An implementation forStreamOptions
A new Subscription on a CloudWatch log group.A fluent builder forSubscriptionFilter
.Properties for a new SubscriptionFilter created from a LogGroup.A builder forSubscriptionFilterOptions
An implementation forSubscriptionFilterOptions
Properties for a SubscriptionFilter.A builder forSubscriptionFilterProps
An implementation forSubscriptionFilterProps