git-annex/doc/git-annex-sim.mdwn

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# NAME
git-annex sim - simulate a network of repositories
# SYNOPSIS
git annex sim start [my.sim]
git annex sim command
git annex sim show
git annex sim end
git annex sim run my.sim
# DESCRIPTION
This command simulates the behavior of git-annex in a network of
repositories, determining which files would reach which repositories
according to the configuration of preferred content, numcopies,
trust level, etc.
The input to the simulation is a sim file, and/or sim commands that are
run after starting it. These are in the form "git annex sim command"
with the command in the same format used in the sim file (see sim commands
list below). For example, "git annex sim step 1" runs the simulation one step.
The simulation keeps a log as it runs, which contains the
entire simulation input, as well as the actions performed in the
simulation, and the results of the simulation. Use "git-annex sim show"
to display the log. This allows re-running the same simulation later,
as well as analyzing the results of the simulation.
Use "git annex sim end" to finish the simulation, and clean up.
As a convenience, to run a sim from a file, and then stop it, use
"git-annex sim run". If there is a problem running the sim, it will be
shown before it is stopped.
# THE SIM FILE
This text file is used to configure the simulation and also to report on
the results of the simulation. Each line takes the form of a command
followed by parameters to the command. Lines starting with "#" or "--"
are comments.
Here is an example sim file:
# add repositories to the simulation and connect them as remotes
init foo
init bar
connect foo <-> bar
# add a special remote
initremote baz
connect foo -> baz <- bar
# configure repositories
numcopies 2
group foo client
wanted foo standard
group bar archive
wanted bar standard
wanted baz include=*.mp3
# add annexed files in the working tree to the simulation, as if they
# were just added to repository foo
addtree foo include=*.mp3
addtree foo include=*.jpg
addtree foo include=bigfiles/
# add simulated annexed files
add bigfile 100gb bar
add hugefile 10tb foo
# run the simulation forward by ten steps
step 10
# remove foo's remote bar and see if a new file added to foo reaches bar
disconnect foo -> bar
add foo.mp3 2mb foo
step 5
# SIM COMMANDS
This is the full set of commands that can be used in the sim file as well
as passed to "git annex sim" while a simulation is running.
* `init name`
Initialize a simulated repository, giving it a name that will be used
in the simulation.
* `initremote name`
Initialize a simulated special remote.
* `use name here|remote|description|uuid`
Use an existing repository in the simulation, with its existing
configuration (trust level, groups, preferred and required content,
maxsize, and the groupwanted configuration of its groups).
The repository is given a name for the purposes of the simulation.
The repository to use can be specified by remote name, uuid, etc.
Example: "use myrepo here"
* `visit repo [command]`
Runs the specified shell command inside the simulated repository,
and waits for it to exit.
When no shell command is specified, it runs an interactive shell.
The command is run in a git repository whosegit-annex branch contains
the state of that simulated repository. This allows running any
git-annex commands, such as `git-annex whereis` to examine the
state of the simulation. You should avoid making any changes to
git-annex state.
* `connect repo [<-|->|<->] repo [...]`
Add a connection between two or more repositories. The arrow indicates
which direction the connection runs, and it can be bidirectional. For
example, "connect foo -> bar" makes bar be a remote of foo, while
"connect foo <-> bar" makes each be the remote of the other. A chain
of connections can extend to many repositories, eg
"connect foo -> bar -> baz -> foo"
* `disconnect repo [<-|->|<->] repo [...]`
Removes connections between repositories.
For example, "disconnect foo -> bar" makes foo no longer have bar as a
remote.
* `addtree repo expression`
Adds annexed files from the git repository to the simulation making them
be present in the specified repository.
The expression is a preferred content expression
(see [[git-annex-preferred-content]](1)) specifying which annexed files
to add. While it is possible to include all or a large number of files
this way, note that often it's more efficient to simulate a small
quantity of files that have the particular properties you are interested
in.
When run in a subdirectory of the repository, only files in that
subdirectory are considered for addition.
This can be used with the same files more than once, to make multiple
repositories in the simulation contain the same files.
* `add filename size repo [repo ...]`
Create a simulated annexed file with the specified filename and size,
that is present in the specified repository, or repositories.
The size can be specified using any usual units, eg "10mb" or
"3.3terabytes"
The filename cannot contain a space.
This stages a file in the index, so that regular git-annex commands can
be used to query the state of the simulated annexed file. If there is
already an annexed file by that name, it will be overwritten with the new
file.
Note that the simulation does not cover adding conflicting files to
different repositories. The files in the simulation are the same across
all simulated repositories.
* `addmulti N suffix minsize maxsize repo [repo ...]
Add multiple simulated annexed files, with random sizes in the range
between minsize and maxsize.
The files are named by combining the number, which starts at 1 and goes
up to N, with the suffix.
For example:
addmulti 100 testfile.jpg 100kb 10mb foo
That adds files named "1testfile.jpg", 2testfile.jpg", etc.
Note that adding a large number of files to the simulation can slow it
down and make it use a lot of memory.
* `step N`
Run the simulation forward by this many steps.
On each step of the simulation, one file is either transferred
or dropped, according to the preferred content and other configuration.
If there are no more files that can be either transferred or dropped
according to the current configuration, a message will be displayed
to indicate that the simulation has stabilized.
This also simulates git pull and git push being run in each repository,
as needed in order to find additional things to do.
* `stepstable N`
Run the simulation forward by this many steps, at which point it is
expected to have stabilized.
If the simulation does not stabilize, the command will exit with a
nonzero exit state.
* `action repo getwanted remote`
Simulate the repository getting files it wants from the remote.
* `action repo dropunwanted`
Simulate the repository dropping files it does not want,
when it is able to verify enough copies exist on remotes.
* `action repo dropunwantedfrom remote`
Simulate the repository dropping files from the remote that the remote
does not want, when it is able to verify enouh copies exist.
* `action repo sendwanted remote`
Simulate the repository sending files that the remote wants to it.
* `action repo gitpush remote`
Simulate the repository pushing the git-annex branch to the remote.
* `action repo gitpull remote`
Simulate the repository pulling the git-annex branch from the remote.
* `action repo pull remote`
Simulate the equivilant of [[git-annex-pull]](1), by combining
the actions gitpull, getwanted, and dropunwanted.
* `action repo push remote`
Simulate the equivilant of [[git-annex-push]](1) by combining
the actions sendwanted, dropunwantedfrom, and gitpush.
* `action repo sync remote`
Simulate the equivilant of [[git-annex-sync]](1) by combining
the actions gitpull, getwanted, sendwanted, dropunwanted, and gitpush.
* `action [...] while action [...]`
Simulate running the two actions concurrently. While the simulation only
actually simulates one thing happening at a time, when the actions each
operate on multiple files, they will be interleaved randomly.
Any number of actions can be combined this way.
For example:
action foo dropunwanted while action bar getwanted foo
In this example, bar may or may not get a file before foo drops it.
* `seed N`
Sets the random seed to a given number. Using this should make the
results of the simulation deterministic. The output sim file
always has the random seed included in it, so it can be used to replay
the simulation.
* `present repo file`
This indicates the expected state of the simulation at this point. The
repository should contain the content of the file. If it does not, the
discrepancy will be indicated on standard error, and the `git-annex sim`
command will eventually exit nonzero.
This is added to the output sim file as the simulation runs.
* `notpresent repo file`
This indicates the expected state of the simulation at this point. The
repository should not contain the content of the file. If it does, the
discrepancy will be indicated on standard error, and the `git-annex sim`
command will eventually exit nonzero.
This is added to the output sim file as the simulation runs.
* `numcopies N`
Sets the desired number of copies. This is equivilant to
[[git-annex-numcopies]](1).
Note that other configuration that sets numcopies, such as .gitattributes
files, is not used by the simulation.
* `mincopies N`
Sets the minimum number of copies. This is equivilant to
[[git-annex-mincopies]](1).
* `trustlevel repo trusted|untrusted|semitrusted|dead`
Sets the trust level of the repository. This is equivilant to
[[git-annex-trust]](1), [[git-annex-untrust]](1), etc.
* `group repo group`
Add a repository to a group. This is equivilant to
[[git-annex-group]](1).
* `ungroup repo group`
Remove a repository from a group. This is equivilant to
[[git-annex-ungroup]](1).
* `wanted repo expression`
Configure the preferred content of a repository. This is equivilant
to [[git-annex-wanted]](1).
* `required repo expression`
Configure the required content of a repository. This is equivilant
to [[git-annex-required]](1).
* `groupwanted group expression`
Configure the groupwanted expression. This is equivilant to
[[git-annex-groupwanted]](1).
* `randomwanted repo term...`
Configure the preferred content of a repository to a random expression
generated by combining a random selection of the provided terms with
"and", "or", and "not".
For example, "randomwanted foo exclude=*.x include=*.x largerthan=100kb"
might generate an expression of "exclude=*.x or not largerthan=100kb and include=*.x"
or it might generate an expression of "include=*.x and exclude=*.x"
* `randomrequired repo term...`
Configure the required content of a repository to a random expression.
* `randomgroupwanted group term...`
Configure the groupwanted to a random expression.
* `maxsize repo size`
Configure the maximum size of a repository. This is equivilant to
[[git-annex-maxsize]](1).
* `rebalance [on|off]`
Setting "rebalance on" is the equivilant of passing the --rebalance
option to git-annex. Setting "rebalance off" undoes that.
For example:
maxsize foo 1tb
rebalance on
step 100
rebalance off
* `clusternode name repo`
Simulate a repository being a node of a cluster, which can be referred to
using the specified name.
Rather than a cluster gateway being simulated as a separate entity, any
connection to a cluster node with that name is treated as accessing that
repository via the same cluster gateway.
Since a cluster gateway knows about all changes that are made to nodes
via it, every repository that has a connection to a cluster node will
immediately know about changes that are made via that node, without
needing a simulated git pull.
To simulate a repository being a node of more than one cluster, or behind
multiple gateways in the same cluster, use this command to give it
multiple names.
# OPTIONS
* The [[git-annex-common-options]](1) can be used.
# SIM FILE COLLECTION
git-annex includes a collection of sim files,
at <https://git-annex.branchable.com/sims/>
# SEE ALSO
[[git-annex]](1)
[[git-annex-test]](1)
# AUTHOR
Joey Hess <id@joeyh.name>
Warning: Automatically converted into a man page by mdwn2man. Edit with care.