How to read var/lib/rpm/Packages content

Question

I have 'Packages' file in path var/lib/rpm in my Centos:8 based image. How can I read/ get 'Packages' file content

As I read in some documentation that this file is of type berkeley DB.. not sure about this.

Answer 1

You may use the "rpm" python library like below, it outputs the same result as

rpm -qa --dbpath /some/path/to/rpm/db

in JSON format

you maybe ignore the _db_backend for now as it's only value is "bdb"

import sys
import rpm
import json

if (len(sys.argv) != 3):
    print ('invalid amount of input arguments!')
    sys.exit()

# user inputs
dbtype = sys.argv[1]
dbpath = sys.argv[2]

# add macro to be used by rpm
rpm.addMacro("_db_backend", dbtype)
rpm.addMacro("_dbpath", dbpath)

# Open database
ts = rpm.TransactionSet()
ts.openDB()

# remove macro for future cases
rpm.delMacro("_db_backend")
rpm.delMacro("_dbpath")

allPackages = []
# retrieve all packages from BDB
mi = ts.dbMatch()

# build JSON object from all packages for easier parsing
for hdr in mi:
    pkgDict = {}
    allPackages.append(pkgDict)
    pkgDict['NAME'] = hdr[rpm.RPMTAG_NAME]
    pkgDict['VERSION'] = hdr[rpm.RPMTAG_VERSION]
    pkgDict['RELEASE'] = hdr[rpm.RPMTAG_RELEASE]
    pkgDict['ARCH'] = hdr[rpm.RPMTAG_ARCH]

print (json.dumps(allPackages))