8939f59403
Co-authored-by: Hector Hurtado <hector.hurtado@bbva.com> Co-authored-by: pancho horrillo <pedrofelipe.horrillo@bbva.com>
142 lines
3.6 KiB
ReStructuredText
142 lines
3.6 KiB
ReStructuredText
User Profile
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============
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Before You Start
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----------------
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Needed Skills:
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#. Basic Linux
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#. Proficient shell
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#. How HTTP works
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Needed Tools:
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#. Linux machine
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#. Installed Kapow! distribution
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Motive
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------
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Use Kapow! to expose some Linux Box internal metrics and actions as an HTTP API for third party users.
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Scenario
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--------
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User is a DevOps at ACME Company.
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ACME Company appears to be a conglomerate which produces and sells every product type imaginable.
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ACME's Infrastructure
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---------------------
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- 2 Linux machines
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- Corporate Server
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- Backup Server
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User Journey
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------------
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#. Actions over the server. Launch database backup script with an HTTP call.
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- User Learns: Add a route that executes a command locally.
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- Kapow! Concepts: `kapow route add`
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- Problem/Motivation: Each time an ACME project is finished it is
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desirable to make a backup of the entire database. Given that the
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database server is a critical machine we don't want to grant SSH
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access to lowly developers. The script is very fast because the
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database is small (for now).
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- Solution: Instead of launching the script via SSH shell we can
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provide an HTTP endpoint to perform the task.
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```
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ssh user@server
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$ ./backup_db.sh
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```
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- Final Kapow!:
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```
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curl -X PUT http://server:8080/db/backup
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```
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```
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kapow route add -X PUT /db/backup -e ./backup_db.sh
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```
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#. Basic server monitoring
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- User Learns: Execute local commands and output it results to the HTTP body.
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- Kapow! Concepts: `kapow set /response/body`
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- Problem/Motivation:
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- Solution:
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- Final Kapow!:
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```
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cat /var/log/backup_db.log | kapow set /response/body
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```
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#. Filter over basic monitoring
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- User Learns: Get a parameter from the user and use it to select the
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script.
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- Kapow! Concepts: `kapow get /request/params`
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- Problem/Motivation:
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- Solution:
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- Final Kapow!:
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```
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LINES="$(kapow get /request/params/lines)"
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FILTER="$(kapow get /request/params/filter)"
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grep "$FILTER" /var/log/backup_db.log \
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| tail -n"$LINES" \
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| kapow set /response/body
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```
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#. Advanced database monitoring
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- User Learns: Compose complex HTTP responses with more than one local command.
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- Kapow! Concepts: HEREDOC and subshells
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- Problem/Motivation:
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- Solution:
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- Final Kapow!:
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```
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{
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echo Memory:
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free -m
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echo ================================================================================
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echo Load:
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uptime
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echo ================================================================================
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echo Disk:
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df -h
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} | kapow set /response/body
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```
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#. Share your achievements
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- User Learns: Format a complex HTTP response with JSON format to feed the corporate dashboard.
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- Kapow! Concepts: backtick interpolation and `kapow set /response/headers`
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- Problem/Motivation:
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- Solution:
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- Final Kapow!:
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``` DON'T HANDWRITE JSON
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echo "{memory: `free -m`, ...uups..}' | kapow set /response/body
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```
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``` USE JQ
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MEMORY=$(free -m)
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LOAD=$(uptime)
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DISK=$(df -h)
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jq -nc --arg memory "$MEMORY" '{"memory": $memory}'
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```
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Ideas
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-----
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- /request/params -> Filter the results of a backup query
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- Use redirects to from one Kapow! server to another. I.e: 192.168.1.1/backups/{path:.*} --> 192.168.1.2/<path>
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- /request/files -> Firma el fichero que sube el usuario y te lo devuelve firmado.
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.. note::
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Add this to serve the webpage that uses the implemented HTTP API
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kapow route add / -c 'kapow set /resonse/headers/Content-Type text/html ; curl --output - http:// | kapow set /response/body'
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