Write up description and add images

Author: bmuschko

13-advanced-jenkinsfile.md

@@ -31,7 +31,7 @@ You can implement the "Test" stage as follows.
 ```groovy
 stage('Test') {
     environment {
-        CODECOV_TOKEN = credentials('codecov_token')
+        CODECOV_TOKEN = credentials('CODECOV_TOKEN')
     }
     steps {
         sh 'go test ./... -coverprofile=coverage.txt'
@@ -63,7 +63,7 @@ stage('Release') {
         buildingTag()
     }
     environment {
-        GITHUB_TOKEN = credentials('github_token')
+        GITHUB_TOKEN = credentials('GITHUB_TOKEN')
     }
     steps {
         sh 'curl -sL https://git.io/goreleaser | bash'

14-shared-library.md

@@ -1,3 +1,104 @@
 # Building Continuous Delivery (CD) Pipelines
 
 ## Writing and using a shared library
+
+1. Set up a new GitHub repository named `jenkins-standard-go-pipeline`. It will define a standard pipeline definition for Go projects implemented as shared library.
+2. Add the file `vars/standard.groovy` that defines the declarative pipeline as global variable. Make the Go tool name and golang-ci version configurable with the help of parameters.
+3. Push the changes to the `master` branch and configure the shared library in Jenkins.
+4. Configure the shared library for consumption in Jenkins with the name `go-pipeline`.
+5. Set up a new GitHub repository named `go-project-by-template`. Initialize a new Go project by running `go mod init github.com/bmuschko/hello-world` and adding a simple `main.go` file.
+6. Add a new `Jenkinsfile`. Consume the shared library and call the global variable.
+7. Trigger a build and visualize the pipeline in Jenkins.
+
+<details><summary>Show Solution</summary>
+<p>
+
+The directory structure of shared library repository should have the following structure.
+
+```
+.
+└── vars
+    └── standard.groovy
+
+1 directory, 1 file
+```
+
+Define the pipeline as global variable in the file `standard.groovy`.
+
+```groovy
+def call(String goToolName = 'go-1.12', String golangCiVersion = 'v1.12.5') {
+    pipeline {
+        agent any
+        tools {
+            go "$goToolName"
+        }
+        environment {
+            GO111MODULE = 'on'
+        }
+        stages {
+            stage('Compile') {
+                steps {
+                    sh 'go build'
+                }
+            }
+            stage('Test') {
+                environment {
+                    CODECOV_TOKEN = credentials('CODECOV_TOKEN')
+                }
+                steps {
+                    sh 'go test ./... -coverprofile=coverage.txt'
+                    sh "curl -s https://codecov.io/bash | bash -s -"
+                }
+            }
+            stage('Code Analysis') {
+                steps {
+                    sh "curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b $GOPATH/bin $golangCiVersion"
+                    sh 'golangci-lint run'
+                }
+            }
+            stage('Release') {
+                when {
+                    buildingTag()
+                }
+                environment {
+                    GITHUB_TOKEN = credentials('GITHUB_TOKEN')
+                }
+                steps {
+                    sh 'curl -sL https://git.io/goreleaser | bash'
+                }
+            }
+        }
+    }
+}
+```
+
+Configure the shared library under _Manage Jenkins > Configure System_.
+
+![Shared Library Configuration](./images/14-shared-library/shared-library-config.png)
+
+The directory structure should look as shown below.
+
+```
+$ tree
+.
+├── Jenkinsfile
+├── go.mod
+└── main.go
+
+0 directories, 3 files
+```
+
+The `Jenkinsfile` uses the shared library and calls the global variable. Optionally, you can configure the pipeline by passing in parameters.
+
+```groovy
+@Library('go-pipeline') _
+
+standard()
+```
+
+The resulting build will go through all the pipeline stages defined in the shared library.
+
+![Pipeline View](./images/14-shared-library/pipeline-view.png)
+
+</p>
+</details>