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Sven Erik Technical Marketing

Transferring Changes Between Perforce Servers

Robert CowhamProfessional Services

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• Background• Algorithm• Configuration

• Adapting for continuous transfer• Customer Case Study

Agenda

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Sven Erik KnopTechnical MarketingPerforce Software

Author of P4Python.

Started as Lead Consultant at Perforce. Regular presenter at Perforce and other conferences.

Robert CowhamProfessional ServicesPerforce Software

API experience includes P4OFC (P4COM) and P4Python. Author of 'Learning Perforce SCM' by PACKT Publishing, Sep 2013.

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Background

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• One project in two separate Perforce Servers?– e.g. Public Depot and Master Depot

Background

Source P4D Target P4D

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• Git? SHAs do not match.• Sandbox? Can only talk to one server.• Replication? Not practical.

• Reconcile? Changes? Integrations?

• Replay changes one by one ... ?

Solutions?

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Idea: two overlapping workspaces• Transfer workspace sharing the same root

transfer

Source Target

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• One workspace on each server with shared root• Client views have to match

– Depot views don’t have to match– Filter projects you want to transfer

• Need to set options to allwrite

Workspace details

Client: src-transRoot: /Users/sknop/perforce/transferOptions: allwriteView:

//source/project1/... //src-trans/...

Client: target-transRoot: /Users/sknop/perforce/transferOptions: allwriteView:

//target/external/... //target-trans/...

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• Written in Python (2.6+ and 3.3+) using P4Python

• Makes use of P4::Map and P4::Resolver– Use Map instead of “p4 where”– Resolver allows scripting of resolve results

Code details

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Algorithm (roughly)counter = getCounter()

changes = p4 –p source changes ...@counter,#head

for change in changes:

if add: p4 –p target add

if delete: p4 –p target delete -v

if edit: p4 –p target sync –k ; p4 –p target edit

integrate?

p4 –p source sync

if move: p4 –p target sync –f old; p4 –p target edit old; p4 –p target move old new

filterChangeByClientView(change)

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• Integrations within workspace view are transferred– Resolve records match source records (details later)

• Integrations from outside the view are downgraded– integrate add/edit/delete

• Use P4::Resolver to preserve resolve outcome

Transferring integrations

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Transferring integrations (cont)

Client: src-transView:

//depot/inside/... //src-trans/...

Client: target-transView:

//target/... //target-trans/...

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• usage: P4Transfer.py [-h] [-n] [-c CONFIG] [-m MAXIMUM] [-k] [-p] [-r] [-s]

• [--sample_config] [-i]

• P4Transfer

• optional arguments:

• -h, --help show this help message and exit

• -n, --preview Preview only, no transfer

• -c CONFIG, --config CONFIG Default is transfer.cfg

• -m MAXIMUM, --maximum MAXIMUM Maximum number of changes to transfer

• -k, --nokeywords Do not expand keywords and remove +k from filetype

• -p, --preflight Run a sanity check first to ensure target is empty

• -r, --repeat Repeat transfer in a loop - for continuous transfer

• -s, --stoponerror Stop on any error even if --repeat has been specified

• --sample_config Print an example config file and exit

• -i, --ignore Treat integrations as adds and edits

Usage

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• [general]

• counter_name = p4transfer_counter

• [source]

• p4port = source.perforce.com:1666

• p4user = sknop

• p4client = source_transfer

• [target]

• p4port = target.perforce.com:1777

• p4user = sknop

• p4client = target_transfer

Configuration file

P4Transfer.py --sample_config

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• How do we test P4Transfer with two servers?• Use the “rsh trick”

– Spawn a local p4d but without consuming portP4PORT=rsh:/bin/p4d -r /path/to/target.root –i

• Tests:– Inject changes into source– Transfer– Verify result in target

Test Harness

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Continuous Transfer

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• Experience based on source code migrations– which can take days

• We want to keep an eye on things– But have a life at the same time

• Reliability/robustness in the face of (communication) errors

• Status / Error reporting to support the above

Background – Long Processes

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• Customer working with multiple third parties• Provide some level of backup/DR• Limited access to remote repositories

– Replicas considered but rejected– Basically only read-only access

• Data size/connectivity issues

Case Study (Background)

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• Volume / connectivity bandwidth– 280 Gb of data

• Seeding via offline backup would have been ideal

– 1Gb per hour transfer rate– Single (early) changelist ~120Gb!

• We wanted– Handle/report VPN disconnects– Peace of mind…!

Data & Connectivity Requirements

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• Use standard Python logging module – Subclass for custom behavior– Beware of Python 2.x/3.x compatibility issues

• Custom logging enhancements– Use circular buffer to remember last 50 lines– Automatically notify users via email, including those

lines

Status/Logging Changes

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Transferring 16 changes

Syncing 16 changes, files 5375, size 11.2 GB

Processing : 87370 "Removed unused physx files from filelist."

source = 87370 : target = 460

Processing : 87377 "Copying //depot/stable to live (//depot/live) various hotfixes"

source = 87377 : target = 461

Synced 8/16 changes, files 676/5375 (12.6 %), size 482.8 MB/11.2 GB (4.3 %)

Synced 8/16 changes, files 940/5375 (17.5 %), size 1.2 GB/11.2 GB (10.7 %)

Sync Status Emails

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• P4API / P4Python has callback options# Report status per change

self.progress.ReportChangeSync()

# Create a custom callback object (next slide)

mycallback = SyncOutput(self.progress)

# Pass it to the P4 sync command

self.p4.run('sync', '...@{},{}'.format(change, change), handler=mycallback )

Sync Status Details

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class SyncOutput(P4.OutputHandler):

def __init__(self, progress):

P4.OutputHandler.__init__(self)

self.progress = progress # Save reporting object

def outputStat(self, stat): # Function called by P4API

if 'fileSize' in stat:

# Report how much data synced for current file

self.progress.ReportFileSync(int(stat['fileSize']))

return P4.OutputHandler.HANDLED

Sync Callback Handler

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• What happens when the Dragon King is:– Der Drachenkönig.jpg

• Windows servers (not in Unicode mode) handle (some) Unicode filenames happily– no P4CHARSET required, but…

• On Mac/Unix - UTF8 does the job• On Windows:

– Python 2.7 fine / Python 3.x requires work…

Unicode

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• On Windows run as a service– Install: srvcinst.exe– Run service: srvany.exe (or other equivalents)

Running Continuously

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• Basic algorithm unchanged– Fixed a couple of bugs– TDD => Test Harness

• Added repeat/polling options• Enhanced Robustness

– Logging / Status reporting– Error handling

Customization Summary

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Questions?Sven Erik Knop sknop@perforce.com

Robert Cowham rcowham@perforce.com@robertcowham

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RESOURCES

Public Depot:swarm.workshop.perforce.com/projects/perforce-software-p4transfer/