...
Avro
...
Component
...
Available
...
as
...
of
...
Camel
...
2.10
...
This
...
component
...
provides
...
a
...
dataformat
...
for
...
avro,
...
which
...
allows
...
serialization
...
and
...
deserialization
...
of
...
messages
...
using
...
Apache
...
Avro's
...
binary
...
dataformat.
...
Moreover,
...
it
...
provides
...
support
...
for
...
Apache
...
Avro's
...
rpc,
...
by
...
providing
...
producers
...
and
...
consumers
...
endpoint
...
for
...
using
...
avro
...
over
...
netty
...
or
...
http.
...
Maven
...
users
...
will
...
need
...
to
...
add
...
the
...
following
...
dependency
...
to
...
their
...
pom.xml
...
for
...
this
...
component:
Code Block | ||||
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{code:xml}
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-avro</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>
|
Apache Avro Overview
Avro allows you to define message types and a protocol using a json like format and then generate java code for the specified types and messages. An example of how a schema looks like is below.
Code Block | ||||
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{code} h3. Apache Avro Overview Avro allows you to define message types and a protocol using a json like format and then generate java code for the specified types and messages. An example of how a schema looks like is below. {code:xml} {"namespace": "org.apache.camel.avro.generated", "protocol": "KeyValueProtocol", "types": [ {"name": "Key", "type": "record", "fields": [ {"name": "key", "type": "string"} ] }, {"name": "Value", "type": "record", "fields": [ {"name": "value", "type": "string"} ] } ], "messages": { "put": { "request": [{"name": "key", "type": "Key"}, {"name": "value", "type": "Value"} ], "response": "null" }, "get": { "request": [{"name": "key", "type": "Key"}], "response": "Value" } } } {code} |
You
...
can
...
easily
...
generate
...
classes
...
from
...
a
...
schema,
...
using
...
maven,
...
ant
...
etc.
...
More
...
details
...
can
...
be
...
found
...
at
...
the
...
...
...
...
.
However,
...
it
...
doesn't
...
enforce
...
a
...
schema
...
first
...
approach
...
and
...
you
...
can
...
create
...
schema
...
for
...
your
...
existing
...
classes.
...
Since
...
2.12
...
you
...
can
...
use
...
existing
...
protocol
...
interfaces
...
to
...
make
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RCP
...
calls.
...
You
...
should
...
use
...
interface
...
for
...
the
...
protocol
...
itself
...
and
...
POJO
...
beans
...
or
...
primitive/String
...
classes
...
for
...
parameter
...
and
...
result
...
types.
...
Here
...
is
...
an
...
example
...
of
...
the
...
class
...
that
...
corresponds
...
to
...
schema
...
above:
Code Block | ||||
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{code:java} package org.apache.camel.avro.reflection; public interface KeyValueProtocol { void put(String key, Value value); Value get(String key); } class Value { private String value; public String getValue() { return value; } public void setValue(String value) { this.value = value; } } {code} _ |
Note:
...
Existing
...
classes
...
can
...
be
...
used
...
only
...
for
...
RPC
...
(see
...
below),
...
not
...
in
...
data
...
format.
Using the Avro data format
Using the avro data format is as easy as specifying that the class that you want to marshal or unmarshal in your route.
Code Block | ||||
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_ h3. Using the Avro data format Using the avro data format is as easy as specifying that the class that you want to marshal or unmarshal in your route. {code:xml} <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:in"/> <marshal> <avro instanceClass="org.apache.camel.dataformat.avro.Message"/> </marshal> <to uri="log:out"/> </route> </camelContext> {code} |
An
...
alternative
...
can
...
be
...
to
...
specify
...
the
...
dataformat
...
inside
...
the
...
context
...
and
...
reference
...
it
...
from
...
your
...
route.
Code Block | ||||
---|---|---|---|---|
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{code:xml} <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring"> <dataFormats> <avro id="avro" instanceClass="org.apache.camel.dataformat.avro.Message"/> </dataFormats> <route> <from uri="direct:in"/> <marshal ref="avro"/> <to uri="log:out"/> </route> </camelContext> {code} |
In
...
the
...
same
...
manner
...
you
...
can
...
umarshal
...
using
...
the
...
avro
...
data
...
format.
...
Using
...
Avro
...
RPC
...
in
...
Camel
...
As
...
mentioned
...
above
...
Avro
...
also
...
provides
...
RPC
...
support
...
over
...
multiple
...
transports
...
such
...
as
...
http
...
and
...
netty.
...
Camel
...
provides
...
consumers
...
and
...
producers
...
for
...
these
...
two
...
transports.
Code Block |
---|
} avro:[transport]:[host]:[port][?options] {code} |
The
...
supported
...
transport
...
values
...
are
...
currently
...
http
...
or
...
netty.
...
Since
...
2.12
...
you
...
can
...
specify
...
message
...
name
...
right
...
in
...
the
...
URI:
Code Block |
---|
} avro:[transport]:[host]:[port][/messageName][?options] {code} |
For
...
consumers
...
this
...
allows
...
you
...
to
...
have
...
multiple
...
routes
...
attached
...
to
...
the
...
same
...
socket.
...
Dispatching
...
to
...
correct
...
route
...
will
...
be
...
done
...
by
...
the
...
avro
...
component
...
automatically.
...
Route
...
with
...
no
...
messageName
...
specified
...
(if
...
any)
...
will
...
be
...
used
...
as
...
default.
...
When
...
using
...
camel
...
producers
...
for
...
avro
...
ipc,
...
the
...
"in"
...
message
...
body
...
needs
...
to
...
contain
...
the
...
parameters
...
of
...
the
...
operation
...
specified
...
in
...
the
...
avro
...
protocol.
...
The
...
response
...
will
...
be
...
added
...
in
...
the
...
body
...
of
...
the
...
"out"
...
message.
...
In
...
a
...
similar
...
manner
...
when
...
using
...
camel
...
avro
...
consumers
...
for
...
avro
...
ipc,
...
the
...
requests
...
parameters
...
will
...
be
...
placed
...
inside
...
the
...
"in"
...
message
...
body
...
of
...
the
...
created
...
exchange
...
and
...
once
...
the
...
exchange
...
is
...
processed
...
the
...
body
...
of
...
the
...
"out"
...
message
...
will
...
be
...
send
...
as
...
a
...
response.
...
Note:
...
By
...
default
...
consumer
...
parameters
...
are
...
wrapped
...
into
...
array.
...
If
...
you've
...
got
...
only
...
one
...
parameter,
...
since
...
2.12
...
you
...
can
...
use
...
singleParameter
...
URI
...
option
...
to
...
receive
...
it
...
direcly
...
in
...
the
...
"in"
...
message
...
body
...
without
...
array
...
wrapping.
...
Avro
...
RPC
...
URI
...
Options
Div | |||||||||||||||
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Avro RPC Headers
Div | ||||
---|---|---|---|---|
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|
Examples
An example of using camel avro producers via http:
Code Block | ||||
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=confluenceTableSmall} || Name || Version || Description || | {{protocolClassName}} | | The class name of the avro protocol. | | {{singleParameter}} | 2.12 | If true, consumer parameter won't be wrapped into array. Will fail if protocol specifies more then 1 parameter for the message | | {{protocol}} | | Avro procol object. Can be used instead of {{protocolClassName}} when complex protocol needs to be created. One cane used #name notation to refer beans from the Registry | | {{reflectionProtocol}} | 2.12 | If protocol object provided is reflection protocol. Should be used only with {{protocol}} parameter because for {{protocolClassName}} protocol type will be autodetected | {div} h3. Avro RPC Headers {div:class=confluenceTableSmall} || Name || Description || | {{CamelAvroMessageName}} | The name of the message to send. In consumer overrides message name from URI (if any)| {div} h3. Examples An example of using camel avro producers via http: {code:xml} <route> <from uri="direct:start"/> <to uri="avro:http:localhost:{{avroport}}?protocolClassName=org.apache.camel.avro.generated.KeyValueProtocol"/> <to uri="log:avro"/> </route> {code} |
In
...
the
...
example
...
above
...
you
...
need
...
to
...
fill
...
CamelAvroMessageName
...
header.
...
Since
...
2.12
...
you
...
can
...
use
...
following
...
syntax
...
to
...
call
...
constant
...
messages:
Code Block | ||||
---|---|---|---|---|
| ||||
{code:xml} <route> <from uri="direct:start"/> <to uri="avro:http:localhost:{{avroport}}/put?protocolClassName=org.apache.camel.avro.generated.KeyValueProtocol"/> <to uri="log:avro"/> </route> {code} |
An
...
example
...
of
...
consuming
...
messages
...
using
...
camel
...
avro
...
consumers
...
via
...
netty:
Code Block | ||||
---|---|---|---|---|
| ||||
{code:xml} <route> <from uri="avro:netty:localhost:{{avroport}}?protocolClassName=org.apache.camel.avro.generated.KeyValueProtocol"/> <choice> <when> <el>${in.headers.CamelAvroMessageName == 'put'}</el> <process ref="putProcessor"/> </when> <when> <el>${in.headers.CamelAvroMessageName == 'get'}</el> <process ref="getProcessor"/> </when> </choice> </route> {code} *Since |
Since 2.12
...
you
...
can
...
set
...
up
...
two
...
distinct
...
routes
...
to
...
perform
...
the
...
same
...
task:
Code Block | ||||
---|---|---|---|---|
| ||||
{code:xml} <route> <from uri="avro:netty:localhost:{{avroport}}/put?protocolClassName=org.apache.camel.avro.generated.KeyValueProtocol"> <process ref="putProcessor"/> </route> <route> <from uri="avro:netty:localhost:{{avroport}}/get?protocolClassName=org.apache.camel.avro.generated.KeyValueProtocol&singleParameter=true"/> <process ref="getProcessor"/> </route> {code} |
In
...
the
...
example
...
above,
...
get
...
takes
...
only
...
one
...
parameter,
...
so
...
singleParameter
...
is
...
used
...
and
...
getProcessor
...
will
...
receive
...
Value
...
class
...
directly
...
in
...
body,
...
while
...
putProcessor
...
will
...
receive
...
an
...
array
...
of
...
size
...
2
...
with
...
String
...
key
...
and
...
Value
...
value
...
filled
...
as
...
array
...
contents.
...