Added the Auto Old Docker Images Delete Script

Author: Lucifergene

old_docker_images_auto_delete/README.md

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+# Auto Cleanup of Older Versions of Docker Images present in a System
+
+During Containerized Deployment of applications, often some VMs are particularly allotted for building the Docker Containers. Whenever a new code change takes place, automatically the CI/CD pipeline triggers the build of a new container containing the latest codes.
+
+Since the VMs have a fixed Disk Size, often storage issues arise, which lead to failure in the building of the containers leading to breakage in the CICD pipeline.
+
+Therefore it's necessary to remove older versions of the container images on a regular basis to avoid storage issues.
+A script has to be written, which would perform the clean-up process based on the image tags.
+
+It will preserve all the docker images containing the latest tag.
+For a particular repository, the tag with the highest number would be preserved.
+A provision is made to add exception images that would be never stopped.
+
+---
+<br>  
+
+## Rules Implemented:
+   
+    1. All images with 'latest' tag would not be touched.
+    2. For a particular repository, the tag with the highest number would be preserved.
+    3. A provision is made to add exception images which would be never stopped.

old_docker_images_auto_delete/main.py

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+# Python Program to auto-delete old docker images
+"""
+    Rules:
+   
+    1. All images with 'latest' tag would not be touched.
+    2. For a particular repository, the tag with the highest number would be preserved.
+    3. A provision is made to add exception images which would be never stopped.
+
+"""
+
+import subprocess as sp
+import re
+import operator, itertools
+
+class DeleteImage:
+    
+    def __init__(self):
+        self.imgList = []
+        self.hashList = []
+        
+
+# Storing All the Docker Image Details Found on the System to a File
+    def getAll(self):
+        file = open("temp.txt","r+")
+        file.truncate(0)
+        sp.run("sudo docker image list --format '{{.Repository}}~{{.Tag}}' >> temp.txt", shell=True , capture_output=True)
+        file.close()
+        
+
+#Add other exceptions here
+    def isExcluded(self , tag):              
+        
+        reg = r"alpine|buster|slim|latest"  #Excluding all the images with Alpine, Buster, Slim & Latest Tags
+        m = re.search(reg, tag)
+        if m != None:
+             return 0        
+        return 1
+    
+# Loading data from the File to the Python program       
+    def loadAll(self):
+        f = open("temp.txt", "r")
+        
+        for line in f:
+            line = line.rstrip("\n")
+            image = line.split('~')
+            if self.isExcluded(image[1]): 
+                
+                regex = r"^(((\d+\.)?(\d+\.)?(\*|\d+)))(\-(dev|stage|prod))*$"        
+                match = re.search(regex, image[1])
+                
+                imgDict = { 'Repository':image[0] , 'Tag': match.group(2) }
+                self.imgList.append(imgDict)      
+        f.close()
+        
+        
+    def manData(self):       
+        key = operator.itemgetter('Repository')
+        b = [{'Repository': x, 'Tag': [d['Tag'] for d in y]} 
+        for x, y in itertools.groupby(sorted(self.imgList, key=key), key=key)]
+        
+        self.imgList.clear()
+        self.imgList = b.copy()
+
+        
+# Sorting Tags according to the Version Numbers    
+    def sortTag(self):
+                
+        for img in self.imgList:                
+            temp = img['Tag'].copy()            
+            
+            for n, i in enumerate(img['Tag']):
+                img['Tag'][n] = int(i.replace('.', ''))
+            
+            maxLen = len(str(max(abs(x) for x in img['Tag'])))            
+            templateString = '{:<0' + str(maxLen) + '}'            
+            finalList = []
+            
+            for n, i in enumerate(img['Tag']):
+                finalList.append(templateString.format(i))
+                
+            for i in range(0 , len(img['Tag'])):
+                hashMap = { 'TagsManipulated': finalList[i] , 'TagsOriginal': temp[i] }
+                self.hashList.append(hashMap)
+                
+            finalList.sort()
+                            
+            img['Tag'].clear()
+            img['Tag'].extend(finalList[:-1])            
+        
+        print(self.hashList)        
+        print (self.imgList)        
+        
+    
+    def hashFunc(self , tag):        
+        for hashMap in self.hashList:
+            if tag == hashMap['TagsManipulated']:
+                t = hashMap['TagsOriginal']
+                break
+            else:
+                t = 'Error in Manipulation'            
+        return t
+    
+# Running the Docker RMI Command to Delete the Older Versions
+    def removeImage(self):        
+        for img in self.imgList:            
+            if img['Tag']:
+                for tag in img['Tag']:
+                    val = self.hashFunc(tag)
+                    imageURL = img['Repository'] + ":" + val
+                    print ("Deleting Image : " + imageURL )
+                    sp.run("sudo docker rmi " + imageURL, shell=True , capture_output=True)
+            
+# Main Function
+if __name__ == "__main__":
+    
+    docker = DeleteImage()
+    docker.getAll()    
+    docker.loadAll()    
+    docker.manData()    
+    docker.sortTag()    
+    docker.removeImage()