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Author SHA1 Message Date
Akemi Izuko fab1f94faa
Parser: add template support 2024-05-26 18:33:08 -06:00
Akemi Izuko 847b2c9596
Readme: init 2024-05-26 18:32:39 -06:00
2 changed files with 220 additions and 2 deletions

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README.md Normal file
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# SSH config+
Streamline repetitive ssh config files with trait-style property inheritance!
ssh_config+ is meant for users with very large and repetitive ssh configs. This
includes templating, an inheretence-style way of copying fields, and for loops
to reduce repetitive lines.
See the `example/` directory for an idea of capabilities, but here's a snippet:
```yaml
__preamble:
ssh_props:
Port: 22
IdentitiesOnly: yes
ForwardX11: no
__uni_template:
template: __preamble
ssh_props:
IdentityFile: ~/.ssh/computer_labs_key
User: emiliko
undergrad:
template: __uni_template
ssh_props:
Hostname: ug22.cs.ualberta.ca
ohaton:
template: __uni_template
ssh_props:
Hostname: ohaton.cs.ualberta.ca
coronation:
template: __uni_template
ssh_props:
Hostname: coronation.cs.ualberta.ca
```
## Rules
The `src/ssh_config_to_yaml.py` script will assist in quickly migrating your
existing config.
#### SSH Properties
Standard SSH config properties go under the `ssh_props` heading for every host.
For example:
```sshconfig
Host github.com
Hostname github.com
IdentityFile ~/.ssh/github_main
LocalForward 3306 localhost:3306
LocalForward 3302 localhost:3302
LocalForward 3000 localhost:3000
```
Becomes:
```yaml
github.com:
ssh_props:
Hostname: github.com
IdentityFile: ~/.ssh/github_main
LocalForward:
- 3306 localhost:3306
- 3302 localhost:3302
- 3000 localhost:3000
```
Note that yaml does not support duplicate keys, so keys can take a list of
properties instead to mimic repeated keys, as seen above.
#### Templates
Templates are "default" properties inherited from another host. Templates must
be declared above the host that uses it. You can make a template-only host by
declaring it with `__` at the start of the name. You can also use another host
as a template.
```yaml
__preamble:
ssh_props:
Port: 22
IdentitiesOnly: yes
ForwardX11: no
#############################################################################
# Uni Computers
#############################################################################
__uni_template:
template: __preamble
ssh_props:
IdentityFile: ~/.ssh/id_ed25519
User: emiliko
ohaton:
template: __uni_template
ssh_props:
Hostname: ohaton.cs.ualberta.ca
coronation:
# Using __uni_template here would make more sense outside an example
template: ohaton
ssh_props:
Hostname: coronation.cs.ualberta.ca
```
Will generate:
```sshconfig
Host ohaton:
ForwardX11 no
Hostname ohaton.cs.ualberta.ca
IdentitiesOnly yes
IdentityFile ~/.ssh/id_ed25519
Port 22
User emiliko
Host coronation:
ForwardX11 no
Hostname coronation.cs.ualberta.ca
IdentitiesOnly yes
IdentityFile ~/.ssh/id_ed25519
Port: 22
User emiliko
```
As a note, properties inherited from templates will be overwritten entirely,
even if they're multi-valued. For example:
```
__uni:
ssh_props:
LocalForward:
- 3306 localhost:3306
- 3302 localhost:3302
- 3000 localhost:3000
ohaton:
template: __uni
ssh_props:
LocalForward:
- 9000 localhost:9000
```
Will overwrite all the `LocalForward` properties provided by the `__uni`
template, generating:
```sshconfig
Host ohaton
LocalForward 9000 localhost:9000
```
#### For loops
For loops allow simple substitution of a single variable over a range or set of
values. Ranges must be numerical, but sets can be any arbitrary string. Multiple
different for loops can be declared under the `for` section.
```yaml
orca:
ssh_props:
Hostname: 10.42.43.1
User emiliko
for:
- variable: port
range:
from: 9026
to: 9042
template: LocalForward ${port} localhost:${port}
- variable: env
range: ["FOO=bar", "BAR=foo"]
template: SendEnv ${env}
```
Expands to:
```sshconfig
Host orca
Hostname 10.42.43.1
LocalForward 9026 localhost:9026
LocalForward 9027 localhost:9027
LocalForward 9028 localhost:9028
LocalForward 9029 localhost:9029
LocalForward 9030 localhost:9030
LocalForward 9031 localhost:9031
LocalForward 9032 localhost:9032
LocalForward 9033 localhost:9033
LocalForward 9034 localhost:9034
LocalForward 9035 localhost:9035
LocalForward 9036 localhost:9036
LocalForward 9037 localhost:9037
LocalForward 9038 localhost:9038
LocalForward 9039 localhost:9039
LocalForward 9040 localhost:9040
LocalForward 9041 localhost:9041
SendEnv FOO=bar
SendEnv BAR=foo
User emiliko
```
For loops can be part of templates

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@ -66,9 +66,12 @@ def expand_for_loop(props):
return expand return expand
def get_ssh_props(data): def get_ssh_props(data, hosts):
props = list() props = list()
if data.get('template'):
props = list(hosts[data.get('template')])
for k, v in data["ssh_props"].items(): for k, v in data["ssh_props"].items():
if isinstance(v, list): if isinstance(v, list):
for x in v: for x in v:
@ -79,6 +82,16 @@ def get_ssh_props(data):
return props return props
def remove_templates(expanded, data):
hosts = dict(expanded)
for host, props in data.items():
if host.startswith('__'):
del hosts[host]
return hosts
def stringify_booleans(props): def stringify_booleans(props):
pattern = re.compile(r"(True|False)$") pattern = re.compile(r"(True|False)$")
@ -101,7 +114,7 @@ def parse_yaml(data):
for host, props in data.items(): for host, props in data.items():
parsed = list() parsed = list()
parsed.extend(get_ssh_props(props)) parsed.extend(get_ssh_props(props, expanded))
parsed.extend(expand_for_loop(props)) parsed.extend(expand_for_loop(props))
parsed = stringify_booleans(parsed) parsed = stringify_booleans(parsed)
@ -109,6 +122,7 @@ def parse_yaml(data):
expanded[host] = sorted(parsed) expanded[host] = sorted(parsed)
expanded = remove_templates(expanded, data)
return expanded return expanded