How to resolve "org.tmatesoft.svn.core.SVNException: svn: E175002: SSL peer shut down incorrectly"?

1. In Jenkins, Nodes > xxx > Monitoring > View Threads to find those threads which naming *svnkit*, kill them.
2. Nodes > xxx > Monitoring > Execute the garbage collector
3. Clean the workspace of related job

Linux nologin and recovery

• checkout someone's shell
• awk -F: '{print $7}' /etc/passwd
• change someone (root) to nologin
• sudo usermod -s `which nologin` root
• recovery
• sudo usermod -s /bin/bash root

SonarQube scan failed when .ts included

In a Jenkins job which invoke SonarQube, it failed with:

ERROR:     throw err;
ERROR:     ^
ERROR: 
ERROR: Error: Cannot find module 'typescript'

How to resolve this? Before SonarQube scanning, we need:

• npm install typescript

Elmah bootstrapper

After .NET Framework 4.x, include Elmah just need:

• *.csproj
• ...
• </ItemGroup>
• <ItemGroup>
•   <PackageReference Include="elmah.bootstrapper" Version="1.0.1" />
• </ItemGroup>
• ...
• Elmah.Athz.config
• ?

Then you can check error by visit http://<YourWebAP>/elmah from any remote

SonarQube method-level complexity

After SonarQube 6.7, file-level complexity still calculated, but method-level complexity gone. The opinion of SonarQube team is Complexity is displayed as a Code Smell. If you still wish to investigate the complexity of your project in method-level, combine those filter:

• Type: Code Smell
• Severity: Critical
• Tag: brain-overload

Update old OpenSSH default DH key size

For Windows 2000, setupssh371-20031015.exe sholud be a good choice for SSH Server / Client. But when connecting to Jenkins as a SSH Publisher, Jenkins complained that DH key size 2047 not valid. How to fix it? Generate by yourself:

• cd "C:\Program Files\OpenSSH\bin"
• ssh-keygen -G moduli-2048.candidates -b 2048
• (wait)
• ssh-keygen -T moduli-2048 -f moduli-2048.candidates
• (wait)
• move moduli-2048 ..\etc\moduli
• del moduli-2048.candidate

New Selenium Node (Chrome / Firefox) on CentOS without GUI

• Assume Selenium Hub listen on docker host 172.17.0.1:4444
• docker (refer this)
• docker-compose (refer this)
• docker-compose.yml (updated from here)
• version: "3"
• services:
• chrome:
• image: selenium/node-chrome:3.141.59-neon
• volumes:
• - /dev/shm:/dev/shm
• environment:
• - HUB_HOST=172.17.0.1
• - HUB_PORT=4444
• - REMOTE_HOST=http://<Host_or_IP>:6666
• - NODE_MAX_INSTANCES=5
• ports:
• - "6666:5555"
• firefox:
• image: selenium/node-firefox:3.141.59-neon
• volumes:
• - /dev/shm:/dev/shm
• environment:
• - HUB_HOST=172.17.0.1
• - HUB_PORT=4444
• - REMOTE_HOST=http://<Host_or_IP>:7777
• - NODE_MAX_INSTANCES=5
• ports:
• - "7777:5555"

Quick Start: Selenium Grid

How can we create a Selenium Grid Environment quickly? If you have docker-compose already, just refer this, save as docker-compose.yml, and run "docker-compose up -d" to start it. That's all.

How to prove it worked? we need:

• selenese-runner.jar download from here
• check your docker host ip address like "ip addr | grep docker0"
• any workable side file

If selenese-runner.jar and my.side in the current directory, start another docker container:

• docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp openjdk java -jar selenese-runner.jar --driver remote --remote-url http://<DOCKER_HOST_IP>:4444/wd/hub --remote-browser <BROWSER> <WORKABLE.side>

<BROWSER> can be chrome or firefox.

CentOS7, Firewalld and Docker

In the past, I always stop firewalld for Docker. But it's not secured. According to this, if we update firewalld version to 0.4.3.2-9 can fix this, or running these command:

• nmcli connection modify docker0 connection.zone trusted
• systemctl stop NetworkManager.service
• firewall-cmd --permanent --zone=trusted --change-interface=docker0
• systemctl start NetworkManager.service
• nmcli connection modify docker0 connection.zone trusted
• systemctl restart docker.service

Jenkins fake warning about Subversion

If a Jenkins job correspond to Subversion, when checking config, maybe you will see this warning:

• Unable to access the repository

Don't worry, this could be a fake warning, if you check Jenkins log and found something like:

• SEVERE hudson.scm.SubversionSCM$ModuleLocation$DescriptorImpl checkCredentialsId
• svn: E200015: Authentication cancelled

selenese runner can't nesting while end loop

Consider this code snippet:

• execute script | return 2; | i
• while | ${i} > 0 |
• execute script | return 3; | j
• while | ${j} > 0 |
• echo | i: ${i}, j: ${j} |
• execute script | return ${j} - 1; | j
• end | |
• execute script | return ${i} - 1; | i
• end | |

It works fine in Selenium IDE with output:

• i: 2, j: 3
• i: 2, j: 2
• i: 2, j: 1
• i: 1, j: 3
• i: 1, j: 2
• i: 1, j: 1

But selenese runner missing some output, just:

• i: 2, j: 3
• i: 2, j: 2
• i: 2, j: 1
• i: 1, j: 3

How can we avoid this inconsistent? this code snippet should be ok:

• execute script | return 2; | i
• do | |
• execute script | return 3; | j
• do | |
• echo | i: ${i}, j: ${j} |
• execute script | return ${j} - 1; | j
• repeat if | ${j} > 0 |
• execute script | return ${i} - 1; | i
• repeat if | ${i} > 0 |

[2019/03/30]

This bug was fixed at version 3.22.0, see here.

On 64 bit Machine, IIS default 64 bit but Visual Studio (IISExpress) default 32 bit

Build WebGoat in a temporary Docker Container

• git clone https://github.com/WebGoat/WebGoat
• cd WebGoat
• docker run -it --rm --name mymaven -v "$(pwd)":/usr/src/mymaven -w /usr/src/mymaven maven:3-jdk-11 mvn clean install

Access your private npm repository - Nexus

• Nexus Server
• install Nexus
• create npm repository (reference)
• grant user / pass
• Nexus Client (Jenkins Node)
• install npm
• npm login --registry https://nexus.acme.com/repository/npm-group/
• (check ~/.npmrc)
• npm --registry https://nexus.acme.com/repository/npm-group/ install somePackage (reference)

Docker & Docker Compose on CentOS

• Docker
• sudo yum install yum-utils
• sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
• sudo yum install docker-ce
• sudo systemctl start docker
• (optional) sudo systemctl enable docker
• sudo usermod -aG docker `whoami`
• (logout, then login again)
• (optional) docker ps
• Docker Compose
• (docker installed)
• (check latest version of Docker Compose from here, ex: 1.23.2)
• sudo curl -L “https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)” -o /usr/local/bin/docker-compose
• sudo chmod +x /usr/local/bin/docker-compose
• (optional) docker-compose --version

Java Restful WebServices

為了想在最少的準備之下開發 Java Restful WebServices，研究了以下的做法：

1. 參考這篇與這篇所述，在 Docker 已安裝的前提下，藉由 Maven webapp plugin，不依賴任何 IDE，建立專案的目錄結構。需要在一個空的目錄下這命令（請自行替換適合的 groupId）：
   docker run -it --rm -v "$(pwd)":/usr/src/mymaven -w /usr/src/mymaven maven mvn archetype:generate -DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-webapp -DgroupId=com.acme -DartifactId=my-webapp
2. 將這群目錄、檔案的擁有權取回：
   sudo chown -R `whoami`. my-webapp
3. 進入 my-webapp 子目錄，補上 src/main/java/com/acme/TestService.java，內容可參考這篇（如果用複製的話，要注意雙引號可能需要替換）。
4. 續上，增加 servlet 與 servlet-mapping 補足 src/main/webapp/WEB-INF/web.xml 的內容，尤其要注意 param-value 與程式中所述的套件、所在路徑一致。
5. 續上，增加三個 dependency 補足 pom.xml 的內容。若在意未來的路徑名稱，也可以增設 build/finalName。
6. 再用 Maven 於 target 目錄產出 war 檔：
   docker run -it --rm -v "$(pwd)":/usr/src/mymaven -w /usr/src/mymaven maven mvn package

接下來的課題是，需要 Servlet Container 讓 war 跑起來，一樣是借重 Docker 與大家最熟悉的 Tomcat：

1. 將 Tomcat 預設埠 8080 8443 都對應好：
   docker run -d --name tomcat -p 8080:8080 -p 8443:8443 tomcat
2. 先確認瀏覽器訪問 8080 沒問題，再設法讓 Manager App 開起來，首先是修改 /usr/local/tomcat/conf/tomcat-users.xml 增加 manager-gui 角色的帳密；若要遠端訪問還有 /usr/local/tomcat/webapps/manager/META-INF/context.xml 要放寬 RemoteAddrValve。
3. 登入 Manager App 之後，部署 war 上去，不論 http://localhost:8080/my-webapp 或 http://localhost:8080/my-webapp/rest/testservice 都應能得到正確內容。
4. 準備 https 憑證與金鑰檔，放到 Docker Container 內，並參考這篇的說明修改 /usr/local/tomcat/conf/server.xml，對應的必要屬性至少有 certificateFile、certificateKeyFile 兩個，就可改由 https 8443 訪問取得結果。