{"componentChunkName":"component---src-pages-author-author-yaml-id-js","path":"/author/mayank-agarwal/","result":{"data":{"allMarkdownRemark":{"edges":[{"node":{"id":"5f19c8b0-c371-5192-b44e-c9bcec168840","html":"

HTTP (hypertext transfer protocol) is a communication protocol that transfers data between client and server. HTTP requests are very essential to access resources from the same or remote server. In Golang, the net/http package comes with the default settings that we need to adjust according to our high-performance requirement.

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For setting up HTTP clients for making requests, most programming languages have different frameworks in place. We will take a hands-on approach in the coming sections to explore how HTTP requests can be made in Golang or Go, as I will refer to the language for the rest of the post.

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While working on the Golang projects, I realized that improper configuration of HTTP might crash your server anytime.

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In the time when I was working with HTTP Client, I Observed some problems and their solutions, listed below:

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Problem:1 Default Http Client

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The HTTP client does not contain the request timeout setting by default.\nIf you are using http.Get(URL) or &Client{} that uses the http.DefaultClient. DefaultClient has not timeout setting; it comes with no timeout

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Suppose the Rest API where you are making the request is broken, not sending the response back that keeps the connection open. More requests came, and open connection count will increase, Increasing server resources utilization, resulting in crashing your server when resource limits are reached.

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Solution: Don't use the default HTTP client, always specify the timeout in http.Client according to your use case

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var httpClient = &http.Client{\n  Timeout: time.Second * 10,\n}
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For the Rest API, it is recommended that timeout should not more than 10 seconds.\nIf the Requested resource is not responded to in 10 seconds, the HTTP connection will be canceled with net/http: request canceled (Client.Timeout exceeded ...) error.

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Problem:2 Default Http Transport

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By default, the Golang Http client performs the connection pooling. When the request completes, that connection remains open until the idle connection timeout (default is 90 seconds). If another request came, that uses the same established connection instead of creating a new connection, after the idle connection time, the connection will return to the pool.

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Using the connection pooling will keep less connection open and more requests will be served with minimal server resources.

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When we not defined transport in the http.Client, it uses the default transport Go HTTP Transport

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Default configuration of the HTTP Transport,

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var DefaultTransport RoundTripper = &Transport{\n\t...\n\tMaxIdleConns:          100,\n\tIdleConnTimeout:       90 * time.Second,\n\t...\n}\n\nconst DefaultMaxIdleConnsPerHost = 2
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MaxIdleConns is the connection pool size, and this is the maximum connection that can be open; its default value is 100 connections.

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There is problem with the default setting DefaultMaxIdleConnsPerHost with value of 2 connection,\nDefaultMaxIdleConnsPerHost is the number of connection can be allowed to open per host basic.\nMeans for any particular host out of 100 connection from the connection pool only two connection will be allocated to that host.

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With the more request came, it will process only two requests; other requests will wait for the connection to communicate with the host server and go in the TIME_WAIT state. As more request came, increase the connection to the TIME_WAIT state and increase the server resource utilization; at the limit, the server will crash.

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Solution: Don't use Default Transport and increase MaxIdleConnsPerHost

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t := http.DefaultTransport.(*http.Transport).Clone()\nt.MaxIdleConns = 100\nt.MaxConnsPerHost = 100\nt.MaxIdleConnsPerHost = 100\n\t\nhttpClient = &http.Client{\n  Timeout:   10 * time.Second,\n  Transport: t,\n}
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By increasing connection per host and the total number of idle connection, this will increase the performance and serve more request with minimal server resources.

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Connection pool size and connection per host count can be increased as per server resources and requirements.

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Conclusion

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In this article, we discussed the problems around the 'net/http' client default configurations. By changing some of the default settings of HTTP Client, we can achieve a High-performance HTTP client for production use. If you want to learn more about http, here is an interesting post on HTTP security headers If you like what you read, share your thoughts in the comment section.

\n","frontmatter":{"title":"How to Use the HTTP Client in GO To Enhance Performance","author":{"id":"Mayank Agarwal","github":"mayankagrwal","avatar":null},"date":"January 12, 2021","updated_date":null,"tags":["Golang","HTTP","Performance"],"coverImage":{"childImageSharp":{"fluid":{"aspectRatio":1.7699115044247788,"src":"/static/68276d4b4277ad09e329598038e91917/14b42/index.jpg","srcSet":"/static/68276d4b4277ad09e329598038e91917/f836f/index.jpg 200w,\n/static/68276d4b4277ad09e329598038e91917/2244e/index.jpg 400w,\n/static/68276d4b4277ad09e329598038e91917/14b42/index.jpg 800w,\n/static/68276d4b4277ad09e329598038e91917/47498/index.jpg 1200w,\n/static/68276d4b4277ad09e329598038e91917/ec6c5/index.jpg 1280w","sizes":"(max-width: 800px) 100vw, 800px"}}}},"fields":{"authorId":"Mayank Agarwal","slug":"/engineering/tune-the-go-http-client-for-high-performance/"}}},{"node":{"id":"6ce369df-8811-5c71-9d65-a5ad1f848f8b","html":"

A JSON Web Token (JWT) is a JSON object that is defined in RFC 7519 as a safe way of transmitting information between two parties. Information in the JWT is digitally-signed, so that it can be verified and trusted.

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JWT Properties

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JWT Use Cases

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JWT contains three parts: Header, Payload, and Signature which are separated by a dot.

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Header.Payload.Signature

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Header

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The JWT Header consists of 2 parts:

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{  \n "typ" : "JWT",  \n "alg" : "HS256"  \n}
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Header Algorithm Types:

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alg Value

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Digital Signature or MAC Algorithm

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AlgoDescription
HS256HMAC using SHA-256 hash algorithm
HS384HMAC using SHA-384 hash algorithm
HS512HMAC using SHA-512 hash algorithm
RS256RSASSA using SHA-256 hash algorithm
RS384RSASSA using SHA-384 hash algorithm
RS512RSASSA using SHA-512 hash algorithm
ES256ECDSA using P-256 curve and SHA-256 hash algorithm
ES384ECDSA using P-384 curve and SHA-384 hash algorithm
ES512ECDSA using P-521 curve and SHA-512 hash algorithm
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The Base64Url-encoded Header, which is first part of our JWT, looks like the following:

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eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9

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Payload

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The Payload, also known as the JWT claim, contains all of the information we want to transmit.

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Different types of claims can be used to build the Payload:

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
CodeNameDescription
ississuerIdentifies the principal that issued the JWT.
subsubjectIdentifies the principal that is the subject of the JWT.
audaudienceIdentifies the recipients that the JWT is intended for.
expExpiration timeIdentifies the expiration time on or after which the JWT MUST NOT be accepted for processing.
nbfNot beforeIdentifies the time before which the JWT MUST NOT be accepted for processing.
iatIssue atIdentifies the time at which the JWT was issued.
jtiJWT idUnique identifier for the JWT, can be used to prevent the JWT from being replayed.
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Example Payload:

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{  \n "sub": "1234567890",  \n "name": "Frank Emic",  \n "jti": "4b5fcea6-2a5e-4a9d-97f2-3d8631ea2c5a",  \n "iat": 1521191902,  \n "exp": 1521195630  \n}
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This example contains a combination of registered and public claims. “sub”,”jti”,”iat”, and “exp” are registered claims and “name” is a public claim.

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The Base64Url-encoded Payload, which is the second part of our JWT, looks like the following:

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eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkZyYW5rIEVtaWMiL  \nCJqdGkiOiI0YjVmY2VhNi0yYTVlLTRhOWQtOTdmMi0zZDg2MzFlYTJjNWEiLCJpYXQiOjE1MjExOTE5MDIsImV4cCI6MTUyMTE5NTYzMH0
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Signature

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The final part of our JWT is the Signature. To create the Signature, we need 3 components:

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var encodedString = base64UrlEncode(header) + \".\" + base64UrlEncode(payload);
\nHMACSHA256(encodedString, 'secret');

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The secret is the Signature held by the server in order to verify tokens and sign new ones.

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The above Base64Url-encoded Header and Payload are combined with a dot, and then digitally-signed using the secret. This generates the Signature as the third part of the our JWT:

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wGDoDSxfKj3Ns379NVxocwM9TOiwxhxWl

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Putting It All Together

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eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkZyYW5rIEVtaWMiL  \nCJqdGkiOiI0YjVmY2VhNi0yYTVlLTRhOWQtOTdmMi0zZDg2MzFlYTJjNWEiLCJpYXQiOjE1MjExOTE5MDIsImV4cCI6MTUyMTE5NTYzMH0.wGDoDSxfKj3Ns379NVxocwM9TOiwxhxWl
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This is our final JWT, containing the Header, Payload, and Signature joined together with dots. It can be passed as a URL parameter, a POST parameter, or in the  HTTP header to authenticate or exchange information.

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You can play around with JWT using our JWT SSO Tool.

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Note: JWT does not hide information; it just encodes information using the digitally-signed signature and verifies that the information has not been altered over the network. So, do not add any sensitive information in the JWT claim.

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Conclusion

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JWT comprises three encoded parts: Header, Payload, and Signature. It can be passed as a URL or POST parameter, or in an HTTP header. Due to JWT's lightweight, self-containing, and versatile strucutre, it remains a popular tool for information exchange and authentication.

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