An Introduction To Web Service
An Introduction To Web Service
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introduction-to-web-service
On Github siddontang / introduction-to-web-service
An Introduction To Web Service
tangliu@kingsoft.com
Agenda
- Introduction
- An Example
- Some Solution
Introduction
What's web service?
A web service is a software function provided at a network address over the web or the cloud (from wiki)
Some Example?
How to do?
- HTTP
- API
- Data Protocol
HTTP
No HTTP, No web. All are based on HTTP!
- HTTP Request
- HTTP Response
API
- RPC http://host/bucket/addFile?name=abc http://host/bucket/getFile?name=abc
- Restful post http://host/bucket/abc get http://host/bucket/abc
Data Protocol
- XML
- JSON
- etc......
Basic for HA Service
- Availability
- Scalability
- Reliability
- Manageability
- etc......
CAP
Example
File Storage Web Service
Two Method:
- upload
- download
Initial Architecture
FS Service: store file
Client: upload or download file from FS Service directly
I think it's like a FTP.
But when files are too many?
Partition
File: Meta + Data Data are stored in difference Data Service Meta Service can find where
How to find?
How to find?
Generality: Hash
- Simple Hash: id(file name) % number(Data Service)
- Consistent Hash
Consistent Hash
Consistent Hash
Control and Data Flow
Many Clients download file data through meta service?
Client request Meta Service to download Meta Service return Data Service location Client download from Data Service directlyRedundancy
Data Storage may corrupted!!!
Backup, when master failed, use backup service!
Cache
Can download more quickly?
- Cache Expired?
- Cache Consistent?
Load Balancer
Meta Service may also have bottleneck!
Proxy
Use proxy for safer download!!!
GFS
Some Solution
Service HA
Heartbeat
Keepalived
MYSQL HA
- Master/Slave
- Master/Master
- Semi-Sync Replication
- etc...