Hello! In this post I will show, in a piece of code, how to execute commands in Docker containers in Groovy or Java. As a dependency, the GitHub library com.github.dockerjava https://github.com/docker-java/docker-java is used.
The code is not that complicated (for Java code), basically you have to enter the Docker URI, container name and a String[] variable with the command to be executed.
The part that may seem a little more laborious is the ResultCallback, basically divided into 3 parts, which would be the equivalent of std_out, std_err and a True or False return.
import com.github.dockerjava.api.DockerClient
import com.github.dockerjava.api.async.ResultCallback
import com.github.dockerjava.api.command.InspectContainerResponse
import com.github.dockerjava.api.model.Frame
import com.github.dockerjava.core.DefaultDockerClientConfig
import com.github.dockerjava.core.DockerClientBuilder
import com.github.dockerjava.core.DockerClientConfig
import com.github.dockerjava.okhttp.OkDockerHttpClient
import com.github.dockerjava.transport.DockerHttpClient
String str_Docker_URI = 'tcp://172.21.5.70:2375';
String str_Container_Name = 'test_python';
String[] lst_Command = new String[]{"/bin/bash", "-c", "counter=0; until [ \$counter -gt 5 ]; do echo \$(date '+%d/%m/%Y %H:%M:%S'); ((counter++)); sleep 1; done"};
class ret_DockerCommand {
Boolean flg_Print = false;
// Boolean flg_Logger = false;
StringBuilder std_out = new StringBuilder();
StringBuilder std_err = new StringBuilder();
Boolean std_complete = false;
def obj_Callback = new ResultCallback.Adapter<Frame>() {
@Override
void onNext(Frame object) {
def str_tmp_result = new String(object.getPayload()).trim();
std_out.append(str_tmp_result);
if (flg_Print) { println(str_tmp_result) }
super.onNext(object);
}
@Override
void onError(Throwable throwable) {
def str_tmp_result = new String(throwable as String).trim();
std_err.append(str_tmp_result);
if (flg_Print) { println(str_tmp_result) }
super.onError(throwable);
}
@Override
void onComplete() {
std_complete=true;
super.onComplete();
}
}
ret_DockerCommand() {
}
ret_DockerCommand(Boolean Flag_Print) {
this.flg_Print=Flag_Print;
}
}
DockerClientConfig obj_dockerClientConfig = DefaultDockerClientConfig.createDefaultConfigBuilder()
.withDockerHost(str_Docker_URI)
.build();
DockerHttpClient obj_httpClient = new OkDockerHttpClient.Builder()
.dockerHost(obj_dockerClientConfig.getDockerHost())
.sslConfig(obj_dockerClientConfig.getSSLConfig())
.build();
DockerClient obj_dockerClient = DockerClientBuilder.getInstance(obj_dockerClientConfig)
.withDockerHttpClient(obj_httpClient)
.build();
InspectContainerResponse obj_container = obj_dockerClient.inspectContainerCmd(str_Container_Name).exec();
try {
final ret_DockerCommand obj_Output = new ret_DockerCommand(true);
var obj_cmd_exec = obj_dockerClient
.execCreateCmd(obj_container.getId())
.withCmd(lst_Command)
.withPrivileged(true)
.withAttachStdout(true)
.exec().getId()
var obj_Return = obj_dockerClient
.execStartCmd(obj_cmd_exec)
.withTty(true)
.exec(obj_Output.obj_Callback)
.awaitCompletion()
println("End");
}
catch (Exception obj_Exception) {
println("Can't exec Docker command" + obj_Exception.toString());
}
Return:
20/05/2024 09:44:49
20/05/2024 09:44:50
20/05/2024 09:44:51
20/05/2024 09:44:52
20/05/2024 09:44:53
20/05/2024 09:44:54
End