Send HTTP Requests

Sending an HTTP request to an external service is a common CI/CD task. In Automation, this task can be generally solved as follows:

Reference a Maven library that provides an HTTP client of your choice (the library must be hosted on Maven Central).
Use the client to send requests in a kotlinScript code block.

For example, the following script gets a random joke from icanhazdadjoke.com and prints it to the job's log. In this example we use the OkHttp client.

@file:DependsOn("com.squareup.okhttp:okhttp:2.7.4", "org.json:json:20200518")

import com.squareup.okhttp.*
import org.json.JSONObject

job("Example") {
    container(image = "amazoncorretto:17-alpine", displayName = "Get random joke") {
        kotlinScript {
            val client = OkHttpClient()
            val request = Request.Builder()
                .url("http://icanhazdadjoke.com")
                .addHeader("Accept", "application/json")
                .build()
            val response = client.newCall(request).execute()
            val jData = response.body().string()
            val jObject = JSONObject(jData)
            val joke = jObject.get("joke").toString()
            println(joke)
        }
    }
}

More complex example: A build script generates a log file with the time log-message data. The task is to send this log to an external service in the JSON format. The service requires authentication with a permanent token. The token is stored in the project's Secrets & Parameters. In this example we use the Ktor HTTP client.

@file:DependsOn("io.ktor:ktor-client-core:1.6.0", "io.ktor:ktor-client-gson:1.6.0")

import io.ktor.client.*
import io.ktor.client.request.*
import io.ktor.http.*

job("Example") {
    container(image = "amazoncorretto:17-alpine", displayName = "Send JSON logs"){
        // get auth token from a project secret
        env["TOKEN"] = Secrets("auth-token")

        kotlinScript {
            // emulate the work of build script by creating a log file
            val file = java.io.File("logs.txt")
            file.writeText("""
                12:00:01 Log message 1
                12:00:02 Log message 2
                12:00:02 Log message 3
            """.trimIndent())

            // convert file to object list
            val log = readLogFile(file)

            // create a Ktor HTTP client
            val client = HttpClient() {
                // install JsonFeature to serialize the data we send
                install(io.ktor.client.features.json.JsonFeature) {
                    // use the Gson serializer
                    serializer = io.ktor.client.features.json.GsonSerializer()
                }
            }

            // get auth token from env var
            val token = System.getenv("TOKEN")

            // send a POST request to external service
            client.post<Unit>("https://external-service.url") {
                headers {
                    // add auth header with bearer token
                    append(HttpHeaders.Authorization, "Bearer $token")
                }
                // the client will serialize log into json
                contentType(ContentType.Application.Json)
                body = log
            }
        }
    }
    // external service receives the payload:
    // [{"time":"12:00:01","msg":"Log message 1"},
    // {"time":"12:00:02","msg":"Log message 2"},
    // {"time":"12:00:02","msg":"Log message 3"}]
}

// representation of a log line
data class LogEntry(val time: String, val msg: String)

fun readLogFile(file: java.io.File): List<LogEntry> {
    val logLines = file.readLines()
    val result = mutableListOf<LogEntry>()

    logLines.forEach {
        val line = it.split(" ", limit = 2)
        val entry = LogEntry(line[0], line[1])
        result.add(entry)
    }

    return result
}

Last modified: 15 December 2023