MongoDB
Since Camel 2.19
Both producer and consumer are supported
According to Wikipedia: "NoSQL is a movement promoting a loosely defined class of non-relational data stores that break with a long history of relational databases and ACID guarantees." NoSQL solutions have grown in popularity in the last few years, and major extremely-used sites and services such as Facebook, LinkedIn, Twitter, etc. are known to use them extensively to achieve scalability and agility.
Basically, NoSQL solutions differ from traditional RDBMS (Relational Database Management Systems) in that they don’t use SQL as their query language and generally don’t offer ACID-like transactional behaviour nor relational data. Instead, they are designed around the concept of flexible data structures and schemas (meaning that the traditional concept of a database table with a fixed schema is dropped), extreme scalability on commodity hardware and blazing-fast processing.
MongoDB is a very popular NoSQL solution and the camel-mongodb component integrates Camel with MongoDB allowing you to interact with MongoDB collections both as a producer (performing operations on the collection) and as a consumer (consuming documents from a MongoDB collection).
MongoDB revolves around the concepts of documents (not as is office documents, but rather hierarchical data defined in JSON/BSON) and collections. This component page will assume you are familiar with them. Otherwise, visit http://www.mongodb.org/.
The MongoDB Camel component uses Mongo Java Driver 4.x. |
Maven users will need to add the following dependency to their pom.xml
for this component:
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-mongodb</artifactId>
<version>x.y.z</version>
<!-- use the same version as your Camel core version -->
</dependency>
URI formats
mongodb:connectionBean?database=databaseName&collection=collectionName&operation=operationName[&moreOptions...] mongodb:dummy?hosts=hostnames&database=databaseName&collection=collectionName&operation=operationName[&moreOptions...]
Configuring Options
Camel components are configured on two separate levels:
-
component level
-
endpoint level
Configuring Component Options
The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.
Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.
Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.
Configuring Endpoint Options
Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.
Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.
A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.
The following two sections lists all the options, firstly for the component followed by the endpoint.
Component Options
The MongoDB component supports 4 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
Autowired Shared client used for connection. All endpoints generated from the component will share this connection client. |
MongoClient |
||
Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored. |
false |
boolean |
|
Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. |
false |
boolean |
|
Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. |
true |
boolean |
Endpoint Options
The MongoDB endpoint is configured using URI syntax:
mongodb:connectionBean
with the following path and query parameters:
Path Parameters (1 parameters)
Name | Description | Default | Type |
---|---|---|---|
Required Sets the connection bean reference used to lookup a client for connecting to a database if no hosts parameter is present. |
String |
Query Parameters (28 parameters)
Name | Description | Default | Type |
---|---|---|---|
Sets the name of the MongoDB collection to bind to this endpoint. |
String |
||
Sets the collection index (JSON FORMAT : \{ field1 : order1, field2 : order2}). |
String |
||
Create collection during initialisation if it doesn’t exist. Default is true. |
true |
boolean |
|
Sets the name of the MongoDB database to target. |
String |
||
Host address of mongodb server in host:port format. It’s possible also use more than one address, as comma separated list of hosts: host1:port1,host2:port2. If the hosts parameter is specified, the provided connectionBean is ignored. |
String |
||
Sets the connection bean used as a client for connecting to a database. |
MongoClient |
||
Sets the operation this endpoint will execute against MongoDB. Enum values:
|
MongoDbOperation |
||
Convert the output of the producer to the selected type : DocumentList Document or MongoIterable. DocumentList or MongoIterable applies to findAll and aggregate. Document applies to all other operations. Enum values:
|
MongoDbOutputType |
||
Consumer type. |
String |
||
Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored. |
false |
boolean |
|
To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored. |
ExceptionHandler |
||
Sets the exchange pattern when the consumer creates an exchange. Enum values:
|
ExchangePattern |
||
Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. |
false |
boolean |
|
MongoDB tailable cursors will block until new data arrives. If no new data is inserted, after some time the cursor will be automatically freed and closed by the MongoDB server. The client is expected to regenerate the cursor if needed. This value specifies the time to wait before attempting to fetch a new cursor, and if the attempt fails, how long before the next attempt is made. Default value is 1000ms. |
1000 |
long |
|
Sets whether this endpoint will attempt to dynamically resolve the target database and collection from the incoming Exchange properties. Can be used to override at runtime the database and collection specified on the otherwise static endpoint URI. It is disabled by default to boost performance. Enabling it will take a minimal performance hit. |
false |
boolean |
|
Configure how MongoDB clients route read operations to the members of a replica set. Possible values are PRIMARY, PRIMARY_PREFERRED, SECONDARY, SECONDARY_PREFERRED or NEAREST. Enum values:
|
PRIMARY |
String |
|
Configure the connection bean with the level of acknowledgment requested from MongoDB for write operations to a standalone mongod, replicaset or cluster. Possible values are ACKNOWLEDGED, W1, W2, W3, UNACKNOWLEDGED, JOURNALED or MAJORITY. Enum values:
|
ACKNOWLEDGED |
String |
|
In write operations, it determines whether instead of returning WriteResult as the body of the OUT message, we transfer the IN message to the OUT and attach the WriteResult as a header. |
false |
boolean |
|
Filter condition for change streams consumer. |
String |
||
The database name associated with the user’s credentials. |
String |
||
User password for mongodb connection. |
String |
||
Username for mongodb connection. |
String |
||
One tail tracking collection can host many trackers for several tailable consumers. To keep them separate, each tracker should have its own unique persistentId. |
String |
||
Enable persistent tail tracking, which is a mechanism to keep track of the last consumed message across system restarts. The next time the system is up, the endpoint will recover the cursor from the point where it last stopped slurping records. |
false |
boolean |
|
Collection where tail tracking information will be persisted. If not specified, MongoDbTailTrackingConfig#DEFAULT_COLLECTION will be used by default. |
String |
||
Indicates what database the tail tracking mechanism will persist to. If not specified, the current database will be picked by default. Dynamicity will not be taken into account even if enabled, i.e. the tail tracking database will not vary past endpoint initialisation. |
String |
||
Field where the last tracked value will be placed. If not specified, MongoDbTailTrackingConfig#DEFAULT_FIELD will be used by default. |
String |
||
Correlation field in the incoming record which is of increasing nature and will be used to position the tailing cursor every time it is generated. The cursor will be (re)created with a query of type: tailTrackIncreasingField greater than lastValue (possibly recovered from persistent tail tracking). Can be of type Integer, Date, String, etc. NOTE: No support for dot notation at the current time, so the field should be at the top level of the document. |
String |
Message Headers
The MongoDB component supports 24 message header(s), which is/are listed below:
Name | Description | Default | Type |
---|---|---|---|
CamelMongoDbOperation (producer) Constant: |
The operation this endpoint will execute against MongoDB. |
MongoDbOperation or String |
|
CamelMongoDbResultTotalSize (producer findAll) Constant: |
Number of objects matching the query. This does not take limit/skip into consideration. |
Integer |
|
CamelMongoDbResultPageSize (producer findAll) Constant: |
Number of objects matching the query. This does not take limit/skip into consideration. |
Integer |
|
CamelMongoDbCriteria (producer) Constant: |
The query to execute against MongoDB. |
Bson |
|
CamelMongoDbFieldsProjection (producer) Constant: |
The project document. |
Bson |
|
CamelMongoDbBatchSize (producer findAll aggregate) Constant: |
The number of documents per batch. |
Integer |
|
CamelMongoDbNumToSkip (producer findAll) Constant: |
Discards a given number of elements at the beginning of the cursor. |
Integer |
|
CamelMongoDbMultiUpdate (producer update) Constant: |
If the update should be applied to all objects matching. See http://www.mongodb.org/display/DOCS/AtomicOperationsAtomic Operations. |
Boolean |
|
CamelMongoDbUpsert (producer update) Constant: |
If the database should create the element if it does not exist. |
Boolean |
|
CamelMongoDbRecordsAffected (producer) Constant: |
The number of modified or deleted records. |
long |
|
CamelMongoDbRecordsMatched (producer) Constant: |
The number of documents matched by the query. |
long |
|
Constant: |
The sort criteria. |
Bson or Document |
|
Constant: |
The name of the MongoDB database to target. |
String |
|
CamelMongoDbCollection (common) Constant: |
The name of the MongoDB collection to bind to this endpoint. |
String |
|
CamelMongoDbCollectionIndex (producer) Constant: |
The list of dynamic indexes to create on the fly. |
List |
|
CamelMongoDbLimit (producer findAll) Constant: |
Limits the number of elements returned. |
Integer |
|
CamelMongoDbTailable (consumer) Constant: |
Is from tailable. |
Boolean |
|
CamelMongoWriteResult (producer) Constant: |
The result of the write operation. |
Object |
|
Constant: |
The OID(s) of the inserted record(s). |
Object or List |
|
CamelMongoDbDistinctQueryField (producer) Constant: |
The specified field name fow which we want to get the distinct values. |
String |
|
CamelMongoDbAllowDiskUse (producer findAll aggregate) Constant: |
Sets allowDiskUse MongoDB flag. This is supported since MongoDB Server 4.3.1. Using this header with older MongoDB Server version can cause query to fail. |
Boolean |
|
CamelMongoDbBulkOrdered (producer bulkWrite) Constant: |
Perform an ordered or unordered operation execution. |
TRUE |
Boolean |
Constant: |
A document that contains the _id of the document created or modified by the insert, replace, delete, update operations (i.e. CRUD operations). For sharded collections, also displays the full shard key for the document. The _id field is not repeated if it is already a part of the shard key. |
ObjectId |
|
CamelMongoDbStreamOperationType (consumer changeStreams) Constant: |
The type of operation that occurred. Can be any of the following values: insert, delete, replace, update, drop, rename, dropDatabase, invalidate. |
String |
Configuration of database in Spring XML
The following Spring XML creates a bean defining the connection to a MongoDB instance.
Since mongo java driver 3, the WriteConcern and readPreference options are not dynamically modifiable. They are defined in the mongoClient object
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mongo="http://www.springframework.org/schema/data/mongo"
xsi:schemaLocation="http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/data/mongo
http://www.springframework.org/schema/data/mongo/spring-mongo.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<mongo:mongo-client id="mongoBean" host="${mongo.url}" port="${mongo.port}" credentials="${mongo.user}:${mongo.pass}@${mongo.dbname}">
<mongo:client-options write-concern="NORMAL" />
</mongo:mongo-client>
</beans>
Sample route
The following route defined in Spring XML executes the operation getDbStats on a collection.
Get DB stats for specified collection
<route>
<from uri="direct:start" />
<!-- using bean 'mongoBean' defined above -->
<to uri="mongodb:mongoBean?database=${mongodb.database}&collection=${mongodb.collection}&operation=getDbStats" />
<to uri="direct:result" />
</route>
MongoDB operations - producer endpoints
Query operations
findById
This operation retrieves only one element from the collection whose _id
field matches the content of the IN message body. The incoming object
can be anything that has an equivalent to a Bson
type. See
http://bsonspec.org/spec.html
and
http://www.mongodb.org/display/DOCS/Java+Types.
from("direct:findById")
.to("mongodb:myDb?database=flights&collection=tickets&operation=findById")
.to("mock:resultFindById");
Please, note that the default _id is treated by Mongo as and ObjectId
type, so you may need to convert it properly.
from("direct:findById")
.convertBodyTo(ObjectId.class)
.to("mongodb:myDb?database=flights&collection=tickets&operation=findById")
.to("mock:resultFindById");
Supports optional parameters This operation supports projection operators. See Specifying a fields filter (projection). |
findOneByQuery
Retrieve the first element from a collection matching a MongoDB query selector.
If the CamelMongoDbCriteria
header is set, then its value is used as the query selector.
If the CamelMongoDbCriteria
header is null, then the IN message body is used as the query
selector. In both cases, the query selector should be of type Bson
or convertible to
Bson
(for instance, a JSON string or HashMap
). See Type conversions for more info.
Create query selectors using the Filters
provided by the MongoDB Driver.
Example without a query selector (returns the first document in a collection)
from("direct:findOneByQuery")
.to("mongodb:myDb?database=flights&collection=tickets&operation=findOneByQuery")
.to("mock:resultFindOneByQuery");
Example with a query selector (returns the first matching document in a collection):
from("direct:findOneByQuery")
.setHeader(MongoDbConstants.CRITERIA, constant(Filters.eq("name", "Raul Kripalani")))
.to("mongodb:myDb?database=flights&collection=tickets&operation=findOneByQuery")
.to("mock:resultFindOneByQuery");
Supports optional parameters This operation supports projection operators and sort clauses. See Specifying a fields filter (projection), Specifying a sort clause. |
findAll
The findAll
operation returns all documents matching a query, or none
at all, in which case all documents contained in the collection are
returned. The query object is extracted CamelMongoDbCriteria
header.
if the CamelMongoDbCriteria header is null the query object is extracted
message body, i.e. it should be of type Bson
or convertible to Bson
.
It can be a JSON String or a Hashmap.
See Type conversions for more info.
Example without a query selector (returns all documents in a collection)
from("direct:findAll")
.to("mongodb:myDb?database=flights&collection=tickets&operation=findAll")
.to("mock:resultFindAll");
Example with a query selector (returns all matching documents in a collection)
from("direct:findAll")
.setHeader(MongoDbConstants.CRITERIA, Filters.eq("name", "Raul Kripalani"))
.to("mongodb:myDb?database=flights&collection=tickets&operation=findAll")
.to("mock:resultFindAll");
Example with option outputType=MongoIterable and batch size
from("direct:findAll")
.setHeader(MongoDbConstants.BATCH_SIZE).constant(10)
.setHeader(MongoDbConstants.CRITERIA, constant(Filters.eq("name", "Raul Kripalani")))
.to("mongodb:myDb?database=flights&collection=tickets&operation=findAll&outputType=MongoIterable")
.to("mock:resultFindAll");
Supports optional parameters This operation supports projection operators and sort clauses. See Specifying a fields filter (projection), Specifying a sort clause. |
count
Returns the total number of objects in a collection, returning a Long as
the OUT message body.
The following example will count the number of records in the
"dynamicCollectionName" collection. Notice how dynamicity is enabled,
and as a result, the operation will not run against the
"notableScientists" collection, but against the "dynamicCollectionName"
collection.
from("direct:count")
.to("mongodb:myDb?database=tickets&collection=flights&operation=count&dynamicity=true");
Long result = template.requestBodyAndHeader("direct:count", "irrelevantBody", MongoDbConstants.COLLECTION, "dynamicCollectionName");
assertTrue("Result is not of type Long", result instanceof Long);
You can provide a query
The query object is extracted CamelMongoDbCriteria
header.
if the CamelMongoDbCriteria header is null the query object is extracted
message body, i.e. it should be of type Bson
or convertible to
Bson
., and
operation will return the amount of documents matching this criteria.
Document query = ...
Long count = template.requestBodyAndHeader("direct:count", query, MongoDbConstants.COLLECTION, "dynamicCollectionName");
Specifying a fields filter (projection)
Query operations will, by default, return the matching objects in their
entirety (with all their fields). If your documents are large and you
only require retrieving a subset of their fields, you can specify a
field filter in all query operations, simply by setting the relevant
Bson
(or type convertible to Bson
, such as a JSON String,
Map, etc.) on the CamelMongoDbFieldsProjection
header, constant shortcut:
MongoDbConstants.FIELDS_PROJECTION
.
Here is an example that uses MongoDB’s Projections
to simplify
the creation of Bson. It retrieves all fields except _id
and
boringField
:
// route: from("direct:findAll").to("mongodb:myDb?database=flights&collection=tickets&operation=findAll")
Bson fieldProjection = Projection.exclude("_id", "boringField");
Object result = template.requestBodyAndHeader("direct:findAll", ObjectUtils.NULL, MongoDbConstants.FIELDS_PROJECTION, fieldProjection);
Here is an example that uses MongoDB’s Projections
to simplify
the creation of Bson. It retrieves all fields except _id
and
boringField
:
// route: from("direct:findAll").to("mongodb:myDb?database=flights&collection=tickets&operation=findAll")
Bson fieldProjection = Projection.exclude("_id", "boringField");
Object result = template.requestBodyAndHeader("direct:findAll", ObjectUtils.NULL, MongoDbConstants.FIELDS_PROJECTION, fieldProjection);
Specifying a sort clause
There is a often a requirement to fetch the min/max record from a
collection based on sorting by a particular field
that uses MongoDB’s Sorts
to simplify
the creation of Bson. It retrieves all fields except _id
and
boringField
:
// route: from("direct:findAll").to("mongodb:myDb?database=flights&collection=tickets&operation=findAll")
Bson sorts = Sorts.descending("_id");
Object result = template.requestBodyAndHeader("direct:findAll", ObjectUtils.NULL, MongoDbConstants.SORT_BY, sorts);
In a Camel route the SORT_BY header can be used with the findOneByQuery
operation to achieve the same result. If the FIELDS_PROJECTION header is also
specified the operation will return a single field/value pair
that can be passed directly to another component (for example, a
parameterized MyBatis SELECT query). This example demonstrates fetching
the temporally newest document from a collection and reducing the result
to a single field, based on the documentTimestamp
field:
.from("direct:someTriggeringEvent")
.setHeader(MongoDbConstants.SORT_BY).constant(Sorts.descending("documentTimestamp"))
.setHeader(MongoDbConstants.FIELDS_PROJECTION).constant(Projection.include("documentTimestamp"))
.setBody().constant("{}")
.to("mongodb:myDb?database=local&collection=myDemoCollection&operation=findOneByQuery")
.to("direct:aMyBatisParameterizedSelect");
Create/update operations
insert
Inserts an new object into the MongoDB collection, taken from the IN
message body. Type conversion is attempted to turn it into Document
or
a List
.
Two modes are supported: single insert and multiple insert. For
multiple insert, the endpoint will expect a List, Array or Collections
of objects of any type, as long as they are - or can be converted to -
Document
.
Example:
from("direct:insert")
.to("mongodb:myDb?database=flights&collection=tickets&operation=insert");
The operation will return a WriteResult, and depending on the
WriteConcern
or the value of the invokeGetLastError
option,
getLastError()
would have been called already or not. If you want to
access the ultimate result of the write operation, you need to retrieve
the CommandResult
by calling getLastError()
or
getCachedLastError()
on the WriteResult
. Then you can verify the
result by calling CommandResult.ok()
,
CommandResult.getErrorMessage()
and/or CommandResult.getException()
.
Note that the new object’s _id
must be unique in the collection. If
you don’t specify the value, MongoDB will automatically generate one for
you. But if you do specify it and it is not unique, the insert operation
will fail (and for Camel to notice, you will need to enable
invokeGetLastError or set a WriteConcern that waits for the write
result).
This is not a limitation of the component, but it is how things work in
MongoDB for higher throughput. If you are using a custom _id
, you are
expected to ensure at the application level that is unique (and this is
a good practice too).
OID(s) of the inserted record(s) is stored in the
message header under CamelMongoOid
key (MongoDbConstants.OID
constant). The value stored is org.bson.types.ObjectId
for single
insert or java.util.List<org.bson.types.ObjectId>
if multiple records
have been inserted.
In MongoDB Java Driver 3.x the insertOne and insertMany operation return void. The Camel insert operation return the Document or List of Documents inserted. Note that each Documents are Updated by a new OID if need.
save
The save operation is equivalent to an upsert (UPdate, inSERT)
operation, where the record will be updated, and if it doesn’t exist, it
will be inserted, all in one atomic operation. MongoDB will perform the
matching based on the _id
field.
Beware that in case of an update, the object is replaced entirely and the usage of MongoDB’s $modifiers is not permitted. Therefore, if you want to manipulate the object if it already exists, you have two options:
-
perform a query to retrieve the entire object first along with all its fields (may not be efficient), alter it inside Camel and then save it.
-
use the update operation with $modifiers, which will execute the update at the server-side instead. You can enable the upsert flag, in which case if an insert is required, MongoDB will apply the $modifiers to the filter query object and insert the result.
If the document to be saved does not contain the _id
attribute, the operation will be an insert, and the new _id
created will be placed in the CamelMongoOid
header.
For example:
from("direct:insert")
.to("mongodb:myDb?database=flights&collection=tickets&operation=save");
// route: from("direct:insert").to("mongodb:myDb?database=flights&collection=tickets&operation=save");
org.bson.Document docForSave = new org.bson.Document();
docForSave.put("key", "value");
Object result = template.requestBody("direct:insert", docForSave);
update
Update one or multiple records on the collection. Requires a filter query and a update rules.
You can define the filter using MongoDBConstants.CRITERIA header as Bson
and define the update rules as Bson
in Body.
Update after enrich While defining the filter by using MongoDBConstants.CRITERIA header as |
The second way Require a List<Bson> as the IN message body containing exactly 2 elements:
-
Element 1 (index 0) ⇒ filter query ⇒ determines what objects will be affected, same as a typical query object
-
Element 2 (index 1) ⇒ update rules ⇒ how matched objects will be updated. All modifier operations from MongoDB are supported.
Multiupdates By default, MongoDB will only update 1 object even if multiple objects
match the filter query. To instruct MongoDB to update all matching
records, set the |
A header with key CamelMongoDbRecordsAffected
will be returned
(MongoDbConstants.RECORDS_AFFECTED
constant) with the number of
records updated (copied from WriteResult.getN()
).
For example, the following will update all records whose filterField field equals true by setting the value of the "scientist" field to "Darwin":
// route: from("direct:update").to("mongodb:myDb?database=science&collection=notableScientists&operation=update");
List<Bson> body = new ArrayList<>();
Bson filterField = Filters.eq("filterField", true);
body.add(filterField);
BsonDocument updateObj = new BsonDocument().append("$set", new BsonDocument("scientist", new BsonString("Darwin")));
body.add(updateObj);
Object result = template.requestBodyAndHeader("direct:update", body, MongoDbConstants.MULTIUPDATE, true);
// route: from("direct:update").to("mongodb:myDb?database=science&collection=notableScientists&operation=update");
Maps<String, Object> headers = new HashMap<>(2);
headers.add(MongoDbConstants.MULTIUPDATE, true);
headers.add(MongoDbConstants.FIELDS_FILTER, Filters.eq("filterField", true));
String updateObj = Updates.set("scientist", "Darwin");;
Object result = template.requestBodyAndHeaders("direct:update", updateObj, headers);
// route: from("direct:update").to("mongodb:myDb?database=science&collection=notableScientists&operation=update");
String updateObj = "[{\"filterField\": true}, {\"$set\", {\"scientist\", \"Darwin\"}}]";
Object result = template.requestBodyAndHeader("direct:update", updateObj, MongoDbConstants.MULTIUPDATE, true);
Delete operations
remove
Remove matching records from the collection. The IN message body will
act as the removal filter query, and is expected to be of type
DBObject
or a type convertible to it.
The following example will remove all objects whose field
'conditionField' equals true, in the science database, notableScientists
collection:
// route: from("direct:remove").to("mongodb:myDb?database=science&collection=notableScientists&operation=remove");
Bson conditionField = Filters.eq("conditionField", true);
Object result = template.requestBody("direct:remove", conditionField);
A header with key CamelMongoDbRecordsAffected
is returned
(MongoDbConstants.RECORDS_AFFECTED
constant) with type int
,
containing the number of records deleted (copied from
WriteResult.getN()
).
Bulk Write Operations
bulkWrite
Performs write operations in bulk with controls for order of execution.
Requires a List<WriteModel<Document>>
as the IN message body containing commands for insert, update, and delete operations.
The following example will insert a new scientist "Pierre Curie", update record with id "5" by setting the value of the "scientist" field to "Marie Curie" and delete record with id "3" :
// route: from("direct:bulkWrite").to("mongodb:myDb?database=science&collection=notableScientists&operation=bulkWrite");
List<WriteModel<Document>> bulkOperations = Arrays.asList(
new InsertOneModel<>(new Document("scientist", "Pierre Curie")),
new UpdateOneModel<>(new Document("_id", "5"),
new Document("$set", new Document("scientist", "Marie Curie"))),
new DeleteOneModel<>(new Document("_id", "3")));
BulkWriteResult result = template.requestBody("direct:bulkWrite", bulkOperations, BulkWriteResult.class);
By default, operations are executed in order and interrupted on the first write error without processing any remaining write operations in the list.
To instruct MongoDB to continue to process remaining write operations in the list, set the CamelMongoDbBulkOrdered
IN message header to false
.
Unordered operations are executed in parallel and this behavior is not guaranteed.
Other operations
aggregate
Perform a aggregation with the given pipeline contained in the body. Aggregations could be long and heavy operations. Use with care.
// route: from("direct:aggregate").to("mongodb:myDb?database=science&collection=notableScientists&operation=aggregate");
List<Bson> aggregate = Arrays.asList(match(or(eq("scientist", "Darwin"), eq("scientist",
group("$scientist", sum("count", 1)));
from("direct:aggregate")
.setBody().constant(aggregate)
.to("mongodb:myDb?database=science&collection=notableScientists&operation=aggregate")
.to("mock:resultAggregate");
By default, a List of all results is returned. This can be heavy on memory depending on the size of the results. A safer alternative is to set your outputType=MongoIterable. The next Processor will see an iterable in the message body allowing it to step through the results one by one. Thus setting a batch size and returning an iterable allows for efficient retrieval and processing of the result.
An example would look like:
List<Bson> aggregate = Arrays.asList(match(or(eq("scientist", "Darwin"), eq("scientist",
group("$scientist", sum("count", 1)));
from("direct:aggregate")
.setHeader(MongoDbConstants.BATCH_SIZE).constant(10)
.setBody().constant(aggregate)
.to("mongodb:myDb?database=science&collection=notableScientists&operation=aggregate&outputType=MongoIterable")
.split(body())
.streaming()
.to("mock:resultAggregate");
Note that calling .split(body())
is enough to send the entries down the route one-by-one, however it would still load all the entries into memory first.
Calling .streaming()
is thus required to load data into memory by batches.
getDbStats
Equivalent of running the db.stats()
command in the MongoDB shell,
which displays useful statistic figures about the database.
For example:
> db.stats(); { "db" : "test", "collections" : 7, "objects" : 719, "avgObjSize" : 59.73296244784423, "dataSize" : 42948, "storageSize" : 1000058880, "numExtents" : 9, "indexes" : 4, "indexSize" : 32704, "fileSize" : 1275068416, "nsSizeMB" : 16, "ok" : 1 }
Usage example:
// from("direct:getDbStats").to("mongodb:myDb?database=flights&collection=tickets&operation=getDbStats");
Object result = template.requestBody("direct:getDbStats", "irrelevantBody");
assertTrue("Result is not of type Document", result instanceof Document);
The operation will return a data structure similar to the one displayed
in the shell, in the form of a Document
in the OUT message body.
getColStats
Equivalent of running the db.collection.stats()
command in the MongoDB
shell, which displays useful statistic figures about the collection.
For example:
> db.camelTest.stats(); { "ns" : "test.camelTest", "count" : 100, "size" : 5792, "avgObjSize" : 57.92, "storageSize" : 20480, "numExtents" : 2, "nindexes" : 1, "lastExtentSize" : 16384, "paddingFactor" : 1, "flags" : 1, "totalIndexSize" : 8176, "indexSizes" : { "_id_" : 8176 }, "ok" : 1 }
Usage example:
// from("direct:getColStats").to("mongodb:myDb?database=flights&collection=tickets&operation=getColStats");
Object result = template.requestBody("direct:getColStats", "irrelevantBody");
assertTrue("Result is not of type Document", result instanceof Document);
The operation will return a data structure similar to the one displayed
in the shell, in the form of a Document
in the OUT message body.
command
Run the body as a command on database. Useful for admin operation as getting host information, replication or sharding status.
Collection parameter is not use for this operation.
// route: from("command").to("mongodb:myDb?database=science&operation=command");
DBObject commandBody = new BasicDBObject("hostInfo", "1");
Object result = template.requestBody("direct:command", commandBody);
Dynamic operations
An Exchange can override the endpoint’s fixed operation by setting the
CamelMongoDbOperation
header, defined by the
MongoDbConstants.OPERATION_HEADER
constant.
The values supported are determined by the MongoDbOperation enumeration
and match the accepted values for the operation
parameter on the
endpoint URI.
For example:
// from("direct:insert").to("mongodb:myDb?database=flights&collection=tickets&operation=insert");
Object result = template.requestBodyAndHeader("direct:insert", "irrelevantBody", MongoDbConstants.OPERATION_HEADER, "count");
assertTrue("Result is not of type Long", result instanceof Long);
Consumers
There are several types of consumers:
-
Tailable Cursor Consumer
-
Change Streams Consumer
Tailable Cursor Consumer
MongoDB offers a mechanism to instantaneously consume ongoing data from
a collection, by keeping the cursor open just like the tail -f
command
of *nix systems. This mechanism is significantly more efficient than a
scheduled poll, due to the fact that the server pushes new data to the
client as it becomes available, rather than making the client ping back
at scheduled intervals to fetch new data. It also reduces otherwise
redundant network traffic.
There is only one requisite to use tailable cursors: the collection must be a "capped collection", meaning that it will only hold N objects, and when the limit is reached, MongoDB flushes old objects in the same order they were originally inserted. For more information, please refer to: http://www.mongodb.org/display/DOCS/Tailable+Cursors.
The Camel MongoDB component implements a tailable cursor consumer,
making this feature available for you to use in your Camel routes. As
new objects are inserted, MongoDB will push them as Document
in natural
order to your tailable cursor consumer, who will transform them to an
Exchange and will trigger your route logic.
How the tailable cursor consumer works
To turn a cursor into a tailable cursor, a few special flags are to be
signalled to MongoDB when first generating the cursor. Once created, the
cursor will then stay open and will block upon calling the
MongoCursor.next()
method until new data arrives. However, the MongoDB
server reserves itself the right to kill your cursor if new data doesn’t
appear after an indeterminate period. If you are interested to continue
consuming new data, you have to regenerate the cursor. And to do so, you
will have to remember the position where you left off or else you will
start consuming from the top again.
The Camel MongoDB tailable cursor consumer takes care of all these tasks for you. You will just need to provide the key to some field in your data of increasing nature, which will act as a marker to position your cursor every time it is regenerated, e.g. a timestamp, a sequential ID, etc. It can be of any datatype supported by MongoDB. Date, Strings and Integers are found to work well. We call this mechanism "tail tracking" in the context of this component.
The consumer will remember the last value of this field and whenever the
cursor is to be regenerated, it will run the query with a filter like:
increasingField > lastValue
, so that only unread data is consumed.
Setting the increasing field: Set the key of the increasing field on
the endpoint URI tailTrackingIncreasingField
option. In Camel 2.10, it
must be a top-level field in your data, as nested navigation for this
field is not yet supported. That is, the "timestamp" field is okay, but
"nested.timestamp" will not work. Please open a ticket in the Camel JIRA
if you do require support for nested increasing fields.
Cursor regeneration delay: One thing to note is that if new data is
not already available upon initialisation, MongoDB will kill the cursor
instantly. Since we don’t want to overwhelm the server in this case, a
cursorRegenerationDelay
option has been introduced (with a default
value of 1000ms.), which you can modify to suit your needs.
An example:
from("mongodb:myDb?database=flights&collection=cancellations&tailTrackIncreasingField=departureTime")
.id("tailableCursorConsumer1")
.autoStartup(false)
.to("mock:test");
The above route will consume from the "flights.cancellations" capped collection, using "departureTime" as the increasing field, with a default regeneration cursor delay of 1000ms.
Persistent tail tracking
Standard tail tracking is volatile and the last value is only kept in memory. However, in practice you will need to restart your Camel container every now and then, but your last value would then be lost and your tailable cursor consumer would start consuming from the top again, very likely sending duplicate records into your route.
To overcome this situation, you can enable the persistent tail tracking feature to keep track of the last consumed increasing value in a special collection inside your MongoDB database too. When the consumer initialises again, it will restore the last tracked value and continue as if nothing happened.
The last read value is persisted on two occasions: every time the cursor is regenerated and when the consumer shuts down. We may consider persisting at regular intervals too in the future (flush every 5 seconds) for added robustness if the demand is there. To request this feature, please open a ticket in the Camel JIRA.
Enabling persistent tail tracking
To enable this function, set at least the following options on the endpoint URI:
-
persistentTailTracking
option totrue
-
persistentId
option to a unique identifier for this consumer, so that the same collection can be reused across many consumers
Additionally, you can set the tailTrackDb
, tailTrackCollection
and
tailTrackField
options to customise where the runtime information will
be stored. Refer to the endpoint options table at the top of this page
for descriptions of each option.
For example, the following route will consume from the
"flights.cancellations" capped collection, using "departureTime" as the
increasing field, with a default regeneration cursor delay of 1000ms,
with persistent tail tracking turned on, and persisting under the
"cancellationsTracker" id on the "flights.camelTailTracking", storing
the last processed value under the "lastTrackingValue" field
(camelTailTracking
and lastTrackingValue
are defaults).
from("mongodb:myDb?database=flights&collection=cancellations&tailTrackIncreasingField=departureTime&persistentTailTracking=true" +
"&persistentId=cancellationsTracker")
.id("tailableCursorConsumer2")
.autoStartup(false)
.to("mock:test");
Below is another example identical to the one above, but where the persistent tail tracking runtime information will be stored under the "trackers.camelTrackers" collection, in the "lastProcessedDepartureTime" field:
from("mongodb:myDb?database=flights&collection=cancellations&tailTrackIncreasingField=departureTime&persistentTailTracking=true" +
"&persistentId=cancellationsTracker&tailTrackDb=trackers&tailTrackCollection=camelTrackers" +
"&tailTrackField=lastProcessedDepartureTime")
.id("tailableCursorConsumer3")
.autoStartup(false)
.to("mock:test");
Change Streams Consumer
Change Streams allow applications to access real-time data changes without the complexity and risk of tailing the MongoDB oplog. Applications can use change streams to subscribe to all data changes on a collection and immediately react to them. Because change streams use the aggregation framework, applications can also filter for specific changes or transform the notifications at will. The exchange body will contain the full document of any change.
To configure Change Streams Consumer you need to specify consumerType
, database
, collection
and optional JSON property streamFilter
to filter events.
That JSON property is standard MongoDB $match
aggregation.
It could be easily specified using XML DSL configuration:
<route id="filterConsumer">
<from uri="mongodb:myDb?consumerType=changeStreams&database=flights&collection=tickets&streamFilter={ '$match':{'$or':[{'fullDocument.stringValue': 'specificValue'}]} }"/>
<to uri="mock:test"/>
</route>
Java configuration:
from("mongodb:myDb?consumerType=changeStreams&database=flights&collection=tickets&streamFilter={ '$match':{'$or':[{'fullDocument.stringValue': 'specificValue'}]} }")
.to("mock:test");
You can externalize the streamFilter value into a property placeholder which allows the endpoint URI parameters to be cleaner and easier to read. |
Type conversions
The MongoDbBasicConverters
type converter included with the
camel-mongodb component provides the following conversions:
Name | From type | To type | How? |
---|---|---|---|
fromMapToDocument |
|
|
constructs a new |
fromDocumentToMap |
|
|
|
fromStringToDocument |
|
|
uses |
fromStringToObjectId |
|
|
constructs a new |
fromFileToDocument |
|
|
uses |
fromInputStreamToDocument |
|
|
converts the inputstream bytes to a |
fromStringToList |
|
|
uses |
This type converter is auto-discovered, so you don’t need to configure anything manually.